ISO 2469:2007

SLOVENSKI STANDARD
SIST ISO 2469:2011
01-maj-2011
Papir, karton, lepenka in vlaknine - Merjenje faktorja razpršene odsevnosti
Paper, board and pulps -- Measurement of diffuse radiance factor
Papier, carton et pâtes -- Mesurage du facteur de luminance énergétique diffuse
Ta slovenski standard je istoveten z: ISO 2469:2007
ICS:
85.040 Vlaknine Pulps
85.060 Papir, karton in lepenka Paper and board
SIST ISO 2469:2011 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST ISO 2469:2011

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SIST ISO 2469:2011

INTERNATIONAL ISO
STANDARD 2469
Fourth edition
2007-06-15

Paper, board and pulps — Measurement
of diffuse radiance factor
Papier, carton et pâtes — Mesurage du facteur de luminance
énergétique diffuse




Reference number
ISO 2469:2007(E)
©
ISO 2007

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SIST ISO 2469:2011
ISO 2469:2007(E)
PDF disclaimer
This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but
shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In
downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat
accepts no liability in this area.
Adobe is a trademark of Adobe Systems Incorporated.
Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation
parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In
the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below.


COPYRIGHT PROTECTED DOCUMENT


©  ISO 2007
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,
electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or
ISO's member body in the country of the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland

ii © ISO 2007 – All rights reserved

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SIST ISO 2469:2011
ISO 2469:2007(E)
Contents Page
Foreword. iv
Introduction . v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions. 1
4 Principle. 3
5 Apparatus . 3
6 Photometric calibration of the instrument and its working standards . 4
7 Sampling. 5
8 Preparation of the test pieces . 5
9 Procedure . 5
10 Calculation and expression of results. 6
11 Precision. 6
12 Test report . 6
Annex A (normative) Instruments for the measurement of radiance factor . 8
Annex B (normative) Calibration service — Photometric calibration. 11
Annex C (normative) Calibration service — UV-adjustment. 13
Annex D (informative) Measurement uncertainty . 15
Annex E (informative) Radiance and reflectance. 18
Bibliography . 19

© ISO 2007 – All rights reserved iii

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SIST ISO 2469:2011
ISO 2469:2007(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 2469 was prepared by Technical Committee ISO/TC 6, Paper, board and pulps.
This fourth edition of ISO 2469 cancels and replaces the third edition (ISO 2469:1994) and
ISO 2469:1994/Cor.1:1998, which have been technically revised. Primarily, certain instrumental features and
computational routines are more rigorously defined in order to meet the requirements of technological
advances and in order to ensure a high precision and reproducibility in the measurement results.
In addition, the property mentioned in the title has been changed from “diffuse reflectance factor” to “diffuse
radiance factor” as an acknowledgement of the fact that many grades of paper now contain added fluorescent
whitening agents. For any given material, the total radiance factor is the sum of the reflected radiance factor
and the luminescent radiance factor, and it is this total property which is the subject of this International
Standard. For pulps and papers not containing any fluorescent component, the radiance factor and the
reflectance factor are synonymous, see Annex E.
iv © ISO 2007 – All rights reserved

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SIST ISO 2469:2011
ISO 2469:2007(E)
Introduction
The radiance factor depends on the conditions of measurement, particularly the spectral and geometric
characteristics of the instrument used. The diffuse radiance factor as defined by this International Standard is
determined using instruments having the characteristics given in Annex A and calibrated according to the
procedure specified in Annex B.
The radiance factor is the sum of the reflected radiance factor and the luminescent radiance factors, and the
radiance factor of a luminescent (fluorescent) object is dependent on the spectral power distribution of the
illumination. The content of UV radiation in the illumination must therefore be set to a specified level if
adequately accurate measurements are to be carried out on fluorescent objects. The preparation of
fluorescent reference standards to enable this adjustment to be made is described in Annex C. The use of
these fluorescent reference standards is described in detail in the International Standards describing the
measurement of the properties of the materials containing fluorescent whitening agents.
The spectral radiance factor or the weighted radiance factor applicable to one or several specified wavelength
bands is often used to characterize the properties of pulp, paper and board. Examples of radiance factors
associated with specified wavelength bands are the ISO brightness (diffuse blue radiance factor) and the
luminance factor.
The radiance factor or reflectance factor is also used as the basis for calculating optical properties, such as
opacity, colour, whiteness and the Kubelka-Munk scattering and absorption coefficients. These various
properties are specified in specific International Standards, for all of which this International Standard is the
primary normative reference.
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SIST ISO 2469:2011

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SIST ISO 2469:2011
INTERNATIONAL STANDARD ISO 2469:2007(E)

Paper, board and pulps — Measurement of diffuse radiance
factor
1 Scope
This International Standard describes the general procedure for measuring the diffuse radiance factor of all
types of pulp, paper and board. More particularly, it specifies in detail in Annex A the characteristics of the
equipment to be used for such measurements, and in Annex B the procedures to be used for calibrating that
equipment.
This International Standard may be used to measure the radiance factors and related properties of materials
containing fluorescent whitening agents, provided that the UV radiation content in the illumination has been
adjusted to the level specified in the specific International Standard describing the measurement of the
property in question.
This International Standard describes in Annex C the preparation of fluorescent reference standards, although
the procedures for using these standards are not included, since their use is described in detail in the specific
International Standards describing the measurement of the properties of materials containing fluorescent
whitening agents.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ISO 186, Paper and board — Sampling to determine average quality
ISO 4094, Paper, board and pulps — International calibration of testing apparatus — Nomination and
acceptance of standardizing and authorized laboratories
ASTM E308-06, Standard Practice for Computing the Colors of Objects by Using the CIE System
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
radiance factor
β
ratio of the radiance of a surface element of a body in the direction delimited by a given cone with its apex at
the surface element to that of the perfect reflecting diffuser under the same conditions of illumination
NOTE For luminescent (fluorescent) materials, the total radiance factor, β, is the sum of two portions, the reflected
radiance factor, β , and the luminescent radiance factor, β , so that:
S L
β = β + β
S L
For non-fluorescent materials, the reflected radiance factor, β , is numerically equal to the reflectance factor, R.
S
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SIST ISO 2469:2011
ISO 2469:2007(E)
3.2
diffuse radiance factor
R
ratio of the radiation reflected and emitted from a body to that reflected from the perfect reflecting diffuser
under the same conditions of diffuse illumination and normal detection
NOTE 1 The ratio is often expressed as a percentage.
NOTE 2 This International Standard prescribes diffuse illumination and normal detection in an instrument constructed
and calibrated in accordance with the provisions of this standard.
3.3
intrinsic radiance factor
R
∞
diffuse radiance factor of a layer or pad of material thick enough to be opaque, i.e., such that increasing the
thickness of the pad by doubling the number of sheets results in no change in the measured radiance factor
NOTE The radiance factor of a single non-opaque sheet is dependent on the background and is not a material
property.
3.4
reflectance factor
ratio of the radiation reflected by a surface element of a body in the direction delimited by a given cone with its
apex at the surface element to that reflected by the perfect reflecting diffuser under the same conditions of
illumination
NOTE 1 The ratio is often expressed as a percentage.
NOTE 2 This term may be used only when it is known that the test material exhibits no luminescence (fluorescence).
3.5
diffuse reflectance factor
R
ratio of the reflection from a body to that from the perfect reflecting diffuser under the same conditions of
diffuse illumination and normal detection
NOTE 1 The ratio is often expressed as a percentage.
NOTE 2 This International Standard specifies diffuse illumination and normal detection in an instrument constructed
and calibrated in accordance with the provisions of this standard.
3.6
intrinsic reflectance factor
R
∞
diffuse reflectance factor of a layer or pad of material thick enough to be opaque, i.e., such that increasing the
thickness of the pad by doubling the number of sheets results in no change in the measured reflectance factor
NOTE The reflectance factor of a single non-opaque sheet is dependent on the background and is not a material
property.
3.7
ISO reference standard of level 1
IR1
the perfect reflecting diffuser (see CIE publication 17.4, No 845.04.54); an ideal spectrally uniform isotropic
Lambertian diffuser with a reflectance equal to 1 at all wavelengths
NOTE Reflectance is defined as the ratio of the reflected to the incident radiation, see Annex E.
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SIST ISO 2469:2011
ISO 2469:2007(E)
3.8
ISO reference standard of level 2
IR2
standard whose radiance factors have been determined by a standardizing laboratory in relation to the IR1 as
defined by ISO 4094
NOTE This International Standard refers to two types of IR2.
A non-fluorescent IR2 whose spectral reflectance factors have been determined by a standardizing laboratory in relation to
the IR1. A non-fluorescent IR2 is used to calibrate the photometric scale of an authorized laboratory’s reference
instrument.
A fluorescent IR2 whose spectral radiance factors corresponding to a specified CIE illuminant have been determined by a
standardizing laboratory. A fluorescent IR2 standard is used to adjust the UV level of an authorized laboratory’s reference
instrument.
3.9
ISO reference standard of level 3
IR3
standard whose radiance factors have been determined by an authorized laboratory in relation to an IR2, as
defined by ISO 4094
NOTE This International Standard refers to two types of IR3.
A non-fluorescent IR3 whose spectral reflectance factors have been determined by an authorized laboratory in relation to
the IR2. A non-fluorescent IR3 is used to calibrate the photometric scale of a testing laboratory’s reference instrument.
A fluorescent IR3 whose calibration values have been determined an authorized laboratory in relation to the IR2. A testing
laboratory uses a fluorescent IR3 to adjust the relative amount of UV radiation incident on the sample to a specified level.
4 Principle
A test piece is irradiated diffusely in a standard instrument and the light reflected (and emitted as a result of
fluorescence) in a direction normal to the surface is passed to a detection system. This detection system may
consist either of a defined optical filter and photodetector or of an array of photodetectors where each detector
responds to a specific effective wavelength. The desired radiance factors are determined directly from the
output from the photodetector in the former case or by calculation from the detector array outputs using
appropriate weighting functions in the latter case.
5 Apparatus
5.1 Reflectometer, having the geometric, spectral and photometric characteristics described in Annex A.
5.2 Reference standards for calibration of the instrument and the working standards, a non-fluorescent
reference standard for photometric calibration of the instrument and its working standards, issued by
an ISO/TC 6 authorized laboratory and fulfilling the requirements for an ISO reference standard of level 3
(see 3.9) as specified in Annex B.
Use reference standards sufficiently frequently to ensure satisfactory calibration.
NOTE If fluorescent materials are to be measured, a fluorescent reference standard issued by an ISO/TC 6
authorized laboratory is required to enable the UV-content of the illumination to be adjusted to correspond to the
appropriate CIE illuminant, as specified in Annex C. The use of these fluorescent reference standards is described in the
International Standards concerned.
5.3 Two non-fluorescent working standards, of opal glass, ceramic or other suitable material with flat
surfaces.
NOTE In some instruments, the function of the primary working standard (see 6.3) may be fulfilled by a built-in
internal standard.
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SIST ISO 2469:2011
ISO 2469:2007(E)
For measurements on fluorescent materials, which require a fluorescent reference standard (see 5.2) to
enable the UV-content of the illumination to be adjusted, stable fluorescent working standards of plastic or
other material incorporating a fluorescent whitening agent are required. These working standards are
described in the relevant International Standards.
5.4 Black cavity, for calibration or validation of the low end of the photometric scale. This black cavity shall
have a radiance factor which does not differ from its nominal value by more than 0,2 percentage points at all
wavelengths. The black cavity should be stored upside-down in a dust-free environment or with a protective
cover. During calibration, the instrument shall be adjusted to the nominal value of the black cavity.
It is not yet possible to institute a system of reference standards to enable testing laboratories to check the
reflectance factor of the black cavity. At the time of delivery, the level should be guaranteed by the instrument
maker. Questions concerning the use and condition of the black cavity should be resolved by contacting the
instrument maker.
6 Photometric calibration of the instrument and its working standards
6.1 Calibration of the instrument
Using the procedure appropriate to the instrument, calibrate the instrument with an IR3. Make a measurement
on the IR3 in order to check that the calibration is satisfactory. The deviation between the measured and the
assigned brightness and/or tristimulus values of the IR3 used for the primary calibration should not exceed
0,05 percentage points.
NOTE Although barium sulfate powders for pressing tablets are commercially available for which the absolute
spectral radiance factors are given on the container, these values are not considered to be traceable according to the
principles of modern metrology, and tablets based on barium sulfate powder are not considered to be suitable for use as
an IR3 as required by this International Standard.
All calibrations are thus related to the IR1 through a calibration chain comprising an IR2 and an IR3 to which
absolute values have been assigned respectively by a standardizing laboratory and by an authorized
laboratory using an instrument conforming to this International Standard.
Handle each IR3 carefully and protect the test area from contamination. Store it in darkness, when not in use.
6.2 Calibration of the non-fluorescent working standards
The non-fluorescent working standards shall be calibrated against ISO reference standards of level 3 in the
instrument in which they are to be used.
Using the procedure appropriate to the instrument, calibrate the instrument with an IR3. Clean the working
standards (see 6.4), measure the working standards and read off and record to the nearest 0,01 percentage
point the radiance factors of the cleaned working standards.
NOTE In order to achieve agreement with the reference instrument, a working standard may be assigned multiple
values, depending upon the working level and the purpose of the measurement. This applies if the working standard is
translucent or glossy and if the linearity of the instrument scale is poor.
6.3 Use of non-fluorescent working standards
Use one plate as a primary working standard for checking and calibrating the instrument, and use the other
much less frequently as a control plate for checking the primary working standard. The frequency with which
the instrument needs to be calibrated depends on the type of instrument. Frequent calibration of the
instrument tends to introduce undesirable fluctuations in the instrument, and the instrument should be
recalibrated only when a check with the primary working standard indicates that calibration is necessary.
Check the primary working standard periodically against the control plate. If any change in the radiance factor
is noticed, clean the primary working standard by the procedure described in 6.4. If the change persists, clean
and recalibrate both working standards against an appropriate IR3 reference standard.
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SIST ISO 2469:2011
ISO 2469:2007(E)
The primary working standard should be checked against the control plate sufficiently often to ensure that any
change in the primary working standard is discovered before an error is introduced into the calibration.
6.4 Cleaning the non-fluorescent working standards
Follow the manufacturer's instructions. In the case of working standards of opal glass or ceramic material,
rinse with distilled water and detergent free from fluorescent ingredients while rubbing with a soft brush. Rinse
thoroughly in distilled water and dry in the air in a dust-free environment without allowing anything to touch the
surface. Leave it in a desiccator until it is optically stable.
7 Sampling
If the tests are being made to evaluate a lot, the sample should be selected in accordance with ISO 186. If the
tests are made on another type of sample, make sure that the test pieces taken are representative of the
sample received.
8 Preparation of the test pieces
Prepare the test pieces according to the instructions given in the relevant International Standard for the
determination of radiance factors or optical properties based on the measurement of radiance factors.
If it is desired simply to measure the radiance factor, rather than some other optical property defined by
another International Standard, follow the following procedure.
Avoiding watermarks, dirt and obvious defects, cut rectangular test pieces approximately 75 mm × 150 mm,
taking care to avoid touching the future test area.
If it is desired to measure the intrinsic radiance factor, assemble test pieces in a pad with their top sides
uppermost; the number should be such that doubling the number of test pieces does not alter the radiance
factor. Protect the pad by placing an additional sheet on both the top and bottom of the pad; avoid contamina-
tion and unnecessary exposure to light or heat. Mark the top test piece in one corner to identify the sample
and its top side.
NOTE If the top side can be distinguished from the wire side, it shall be uppermost; if not, as may be the case for
papers manufactured on double wire machines, ensure that the same side of the sheet is uppermost throughout the pad.
If sufficient sheets are not available or if it is desired to measure a background-dependent radiance factor,
select a suitable background and include a description of this background in the report.
9 Procedure
Determine the radiance factor as specified in the relevant International Standard for the determination of
radiance factors or optical properties based on the measurement of radiance factors.
If it is desired simply to measure the radiance factor, rather than some other optical property defined by
another International Standard, follow the following procedure.
9.1 Verification of calibration
Check the calibration of the instrument using a non-fluorescent working standard calibrated in relation to an
IR3 (5.3). Recalibrate the instrument if necessary.
NOTE If the instrument is of the spectrophotometer type, and if the material to be measured contains or is suspected
to contain a fluorescent component, the UV content of the illumination must be adjusted to match the desired illuminant
using the fluorescent (5.2) and non-fluorescent (see 5.2) ISO level 3 standards in an iterative procedure according to the
instrument maker's instructions. The procedure for UV-adjustment to match the CIE standard illuminant D65 is given in
ISO 11475 and for UV-adjustment to match the CIE illuminant C in ISO 2470.
© ISO 2007 – All rights reserved 5

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SIST ISO 2469:2011
ISO 2469:2007(E)
9.2 Measurement
Remove the protecting sheets from the test piece pad. Without touching the test area, use the procedure
appropriate to the instrument, and the working standard, to measure the desired radiance factor. Read and
record the value to the nearest 0,01 percentage points or better.
10 Calculation and expression of results
Express the radiance factor results with the number of decimals appropriate to the uncertainty and
reproducibility of the procedure.
Calculate the results as required in the relevant International Standard for the determination of radiance
factors or optical properties based on the measurement of radiance factors, e.g.:
ISO 2470, Paper, board and pulps — Measurement of diffuse blue reflectance factor (ISO brightness)
ISO 2471, Paper and board — Determination of opacity (paper backing) — Diffuse reflectance method
ISO 5631, Paper and board — Determination of colour (C/2°) — Diffuse reflectance method
ISO 9416, Paper — Determination of light scattering and absorption coefficients (using Kubelka-Munk theory)
ISO 11475, Paper and board — Determination of CIE-whiteness, D65/10° (outdoor daylight)
ISO 11476, Paper and board — Determination of CIE-whiteness, C/2° (indoor illumination conditions)
NOTE Some informative comments on the definition and calculation of the measurement uncertainty are given in
Annex D.
11 Precision
Data relating to the precision of results obtained according to the procedure described in this International
Standard are given in the relevant test method for the determination of radiance factors or optical properties
based on the measurement of radiance factors. (See also Annex D).
12 Test report
Report the results as indicated in the relevant International Standard for the determination of radiance factors
or optical properties based on the measurement of radiance factors.
If a radiance factor is determined according to the procedure described in this International Standard, the test
report shall include the following details:
a) date and place of testing;
b) precise identification of the sample;
c) a reference to this International Standard;
d) the test results;
e) the wavelength range, pitch and bandwidth if a spectrophotometer is used, or the type of filter if a filter
instrument is used;
f) the illuminant to which the UV-content of the illumination is adjusted if a spectrophotometer is used;
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SIST ISO 2469:2011
ISO 2469:2007(E)
g) the number of test pieces and the procedure adopted to calculate the reported results;
h) the type of instrument used;
i) any departure from this International Standard or any circumstances or influences that may have affected
the results.
© ISO 2007 – All rights reserved 7

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SIST ISO 2469:2011
ISO 2469:2007(E)
Annex A
(normative)

Instruments for the measurement of radiance factor
The geometric, photometric and spectral characteristics of the instruments to which this International Standard
applies are defined as follows:
A.1 Geometric characteristics
A.1.1 The test piece and reference area shall be subjected to diffuse illumination which is achieved by
means of an integratin
...

INTERNATIONAL ISO
STANDARD 2469
Fourth edition
2007-06-15

Paper, board and pulps — Measurement
of diffuse radiance factor
Papier, carton et pâtes — Mesurage du facteur de luminance
énergétique diffuse




Reference number
ISO 2469:2007(E)
©
ISO 2007

---------------------- Page: 1 ----------------------
ISO 2469:2007(E)
PDF disclaimer
This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but
shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In
downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat
accepts no liability in this area.
Adobe is a trademark of Adobe Systems Incorporated.
Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation
parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In
the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below.


COPYRIGHT PROTECTED DOCUMENT


©  ISO 2007
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,
electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or
ISO's member body in the country of the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland

ii © ISO 2007 – All rights reserved

---------------------- Page: 2 ----------------------
ISO 2469:2007(E)
Contents Page
Foreword. iv
Introduction . v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions. 1
4 Principle. 3
5 Apparatus . 3
6 Photometric calibration of the instrument and its working standards . 4
7 Sampling. 5
8 Preparation of the test pieces . 5
9 Procedure . 5
10 Calculation and expression of results. 6
11 Precision. 6
12 Test report . 6
Annex A (normative) Instruments for the measurement of radiance factor . 8
Annex B (normative) Calibration service — Photometric calibration. 11
Annex C (normative) Calibration service — UV-adjustment. 13
Annex D (informative) Measurement uncertainty . 15
Annex E (informative) Radiance and reflectance. 18
Bibliography . 19

© ISO 2007 – All rights reserved iii

---------------------- Page: 3 ----------------------
ISO 2469:2007(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 2469 was prepared by Technical Committee ISO/TC 6, Paper, board and pulps.
This fourth edition of ISO 2469 cancels and replaces the third edition (ISO 2469:1994) and
ISO 2469:1994/Cor.1:1998, which have been technically revised. Primarily, certain instrumental features and
computational routines are more rigorously defined in order to meet the requirements of technological
advances and in order to ensure a high precision and reproducibility in the measurement results.
In addition, the property mentioned in the title has been changed from “diffuse reflectance factor” to “diffuse
radiance factor” as an acknowledgement of the fact that many grades of paper now contain added fluorescent
whitening agents. For any given material, the total radiance factor is the sum of the reflected radiance factor
and the luminescent radiance factor, and it is this total property which is the subject of this International
Standard. For pulps and papers not containing any fluorescent component, the radiance factor and the
reflectance factor are synonymous, see Annex E.
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ISO 2469:2007(E)
Introduction
The radiance factor depends on the conditions of measurement, particularly the spectral and geometric
characteristics of the instrument used. The diffuse radiance factor as defined by this International Standard is
determined using instruments having the characteristics given in Annex A and calibrated according to the
procedure specified in Annex B.
The radiance factor is the sum of the reflected radiance factor and the luminescent radiance factors, and the
radiance factor of a luminescent (fluorescent) object is dependent on the spectral power distribution of the
illumination. The content of UV radiation in the illumination must therefore be set to a specified level if
adequately accurate measurements are to be carried out on fluorescent objects. The preparation of
fluorescent reference standards to enable this adjustment to be made is described in Annex C. The use of
these fluorescent reference standards is described in detail in the International Standards describing the
measurement of the properties of the materials containing fluorescent whitening agents.
The spectral radiance factor or the weighted radiance factor applicable to one or several specified wavelength
bands is often used to characterize the properties of pulp, paper and board. Examples of radiance factors
associated with specified wavelength bands are the ISO brightness (diffuse blue radiance factor) and the
luminance factor.
The radiance factor or reflectance factor is also used as the basis for calculating optical properties, such as
opacity, colour, whiteness and the Kubelka-Munk scattering and absorption coefficients. These various
properties are specified in specific International Standards, for all of which this International Standard is the
primary normative reference.
© ISO 2007 – All rights reserved v

---------------------- Page: 5 ----------------------
INTERNATIONAL STANDARD ISO 2469:2007(E)

Paper, board and pulps — Measurement of diffuse radiance
factor
1 Scope
This International Standard describes the general procedure for measuring the diffuse radiance factor of all
types of pulp, paper and board. More particularly, it specifies in detail in Annex A the characteristics of the
equipment to be used for such measurements, and in Annex B the procedures to be used for calibrating that
equipment.
This International Standard may be used to measure the radiance factors and related properties of materials
containing fluorescent whitening agents, provided that the UV radiation content in the illumination has been
adjusted to the level specified in the specific International Standard describing the measurement of the
property in question.
This International Standard describes in Annex C the preparation of fluorescent reference standards, although
the procedures for using these standards are not included, since their use is described in detail in the specific
International Standards describing the measurement of the properties of materials containing fluorescent
whitening agents.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ISO 186, Paper and board — Sampling to determine average quality
ISO 4094, Paper, board and pulps — International calibration of testing apparatus — Nomination and
acceptance of standardizing and authorized laboratories
ASTM E308-06, Standard Practice for Computing the Colors of Objects by Using the CIE System
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
radiance factor
β
ratio of the radiance of a surface element of a body in the direction delimited by a given cone with its apex at
the surface element to that of the perfect reflecting diffuser under the same conditions of illumination
NOTE For luminescent (fluorescent) materials, the total radiance factor, β, is the sum of two portions, the reflected
radiance factor, β , and the luminescent radiance factor, β , so that:
S L
β = β + β
S L
For non-fluorescent materials, the reflected radiance factor, β , is numerically equal to the reflectance factor, R.
S
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3.2
diffuse radiance factor
R
ratio of the radiation reflected and emitted from a body to that reflected from the perfect reflecting diffuser
under the same conditions of diffuse illumination and normal detection
NOTE 1 The ratio is often expressed as a percentage.
NOTE 2 This International Standard prescribes diffuse illumination and normal detection in an instrument constructed
and calibrated in accordance with the provisions of this standard.
3.3
intrinsic radiance factor
R
∞
diffuse radiance factor of a layer or pad of material thick enough to be opaque, i.e., such that increasing the
thickness of the pad by doubling the number of sheets results in no change in the measured radiance factor
NOTE The radiance factor of a single non-opaque sheet is dependent on the background and is not a material
property.
3.4
reflectance factor
ratio of the radiation reflected by a surface element of a body in the direction delimited by a given cone with its
apex at the surface element to that reflected by the perfect reflecting diffuser under the same conditions of
illumination
NOTE 1 The ratio is often expressed as a percentage.
NOTE 2 This term may be used only when it is known that the test material exhibits no luminescence (fluorescence).
3.5
diffuse reflectance factor
R
ratio of the reflection from a body to that from the perfect reflecting diffuser under the same conditions of
diffuse illumination and normal detection
NOTE 1 The ratio is often expressed as a percentage.
NOTE 2 This International Standard specifies diffuse illumination and normal detection in an instrument constructed
and calibrated in accordance with the provisions of this standard.
3.6
intrinsic reflectance factor
R
∞
diffuse reflectance factor of a layer or pad of material thick enough to be opaque, i.e., such that increasing the
thickness of the pad by doubling the number of sheets results in no change in the measured reflectance factor
NOTE The reflectance factor of a single non-opaque sheet is dependent on the background and is not a material
property.
3.7
ISO reference standard of level 1
IR1
the perfect reflecting diffuser (see CIE publication 17.4, No 845.04.54); an ideal spectrally uniform isotropic
Lambertian diffuser with a reflectance equal to 1 at all wavelengths
NOTE Reflectance is defined as the ratio of the reflected to the incident radiation, see Annex E.
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ISO 2469:2007(E)
3.8
ISO reference standard of level 2
IR2
standard whose radiance factors have been determined by a standardizing laboratory in relation to the IR1 as
defined by ISO 4094
NOTE This International Standard refers to two types of IR2.
A non-fluorescent IR2 whose spectral reflectance factors have been determined by a standardizing laboratory in relation to
the IR1. A non-fluorescent IR2 is used to calibrate the photometric scale of an authorized laboratory’s reference
instrument.
A fluorescent IR2 whose spectral radiance factors corresponding to a specified CIE illuminant have been determined by a
standardizing laboratory. A fluorescent IR2 standard is used to adjust the UV level of an authorized laboratory’s reference
instrument.
3.9
ISO reference standard of level 3
IR3
standard whose radiance factors have been determined by an authorized laboratory in relation to an IR2, as
defined by ISO 4094
NOTE This International Standard refers to two types of IR3.
A non-fluorescent IR3 whose spectral reflectance factors have been determined by an authorized laboratory in relation to
the IR2. A non-fluorescent IR3 is used to calibrate the photometric scale of a testing laboratory’s reference instrument.
A fluorescent IR3 whose calibration values have been determined an authorized laboratory in relation to the IR2. A testing
laboratory uses a fluorescent IR3 to adjust the relative amount of UV radiation incident on the sample to a specified level.
4 Principle
A test piece is irradiated diffusely in a standard instrument and the light reflected (and emitted as a result of
fluorescence) in a direction normal to the surface is passed to a detection system. This detection system may
consist either of a defined optical filter and photodetector or of an array of photodetectors where each detector
responds to a specific effective wavelength. The desired radiance factors are determined directly from the
output from the photodetector in the former case or by calculation from the detector array outputs using
appropriate weighting functions in the latter case.
5 Apparatus
5.1 Reflectometer, having the geometric, spectral and photometric characteristics described in Annex A.
5.2 Reference standards for calibration of the instrument and the working standards, a non-fluorescent
reference standard for photometric calibration of the instrument and its working standards, issued by
an ISO/TC 6 authorized laboratory and fulfilling the requirements for an ISO reference standard of level 3
(see 3.9) as specified in Annex B.
Use reference standards sufficiently frequently to ensure satisfactory calibration.
NOTE If fluorescent materials are to be measured, a fluorescent reference standard issued by an ISO/TC 6
authorized laboratory is required to enable the UV-content of the illumination to be adjusted to correspond to the
appropriate CIE illuminant, as specified in Annex C. The use of these fluorescent reference standards is described in the
International Standards concerned.
5.3 Two non-fluorescent working standards, of opal glass, ceramic or other suitable material with flat
surfaces.
NOTE In some instruments, the function of the primary working standard (see 6.3) may be fulfilled by a built-in
internal standard.
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For measurements on fluorescent materials, which require a fluorescent reference standard (see 5.2) to
enable the UV-content of the illumination to be adjusted, stable fluorescent working standards of plastic or
other material incorporating a fluorescent whitening agent are required. These working standards are
described in the relevant International Standards.
5.4 Black cavity, for calibration or validation of the low end of the photometric scale. This black cavity shall
have a radiance factor which does not differ from its nominal value by more than 0,2 percentage points at all
wavelengths. The black cavity should be stored upside-down in a dust-free environment or with a protective
cover. During calibration, the instrument shall be adjusted to the nominal value of the black cavity.
It is not yet possible to institute a system of reference standards to enable testing laboratories to check the
reflectance factor of the black cavity. At the time of delivery, the level should be guaranteed by the instrument
maker. Questions concerning the use and condition of the black cavity should be resolved by contacting the
instrument maker.
6 Photometric calibration of the instrument and its working standards
6.1 Calibration of the instrument
Using the procedure appropriate to the instrument, calibrate the instrument with an IR3. Make a measurement
on the IR3 in order to check that the calibration is satisfactory. The deviation between the measured and the
assigned brightness and/or tristimulus values of the IR3 used for the primary calibration should not exceed
0,05 percentage points.
NOTE Although barium sulfate powders for pressing tablets are commercially available for which the absolute
spectral radiance factors are given on the container, these values are not considered to be traceable according to the
principles of modern metrology, and tablets based on barium sulfate powder are not considered to be suitable for use as
an IR3 as required by this International Standard.
All calibrations are thus related to the IR1 through a calibration chain comprising an IR2 and an IR3 to which
absolute values have been assigned respectively by a standardizing laboratory and by an authorized
laboratory using an instrument conforming to this International Standard.
Handle each IR3 carefully and protect the test area from contamination. Store it in darkness, when not in use.
6.2 Calibration of the non-fluorescent working standards
The non-fluorescent working standards shall be calibrated against ISO reference standards of level 3 in the
instrument in which they are to be used.
Using the procedure appropriate to the instrument, calibrate the instrument with an IR3. Clean the working
standards (see 6.4), measure the working standards and read off and record to the nearest 0,01 percentage
point the radiance factors of the cleaned working standards.
NOTE In order to achieve agreement with the reference instrument, a working standard may be assigned multiple
values, depending upon the working level and the purpose of the measurement. This applies if the working standard is
translucent or glossy and if the linearity of the instrument scale is poor.
6.3 Use of non-fluorescent working standards
Use one plate as a primary working standard for checking and calibrating the instrument, and use the other
much less frequently as a control plate for checking the primary working standard. The frequency with which
the instrument needs to be calibrated depends on the type of instrument. Frequent calibration of the
instrument tends to introduce undesirable fluctuations in the instrument, and the instrument should be
recalibrated only when a check with the primary working standard indicates that calibration is necessary.
Check the primary working standard periodically against the control plate. If any change in the radiance factor
is noticed, clean the primary working standard by the procedure described in 6.4. If the change persists, clean
and recalibrate both working standards against an appropriate IR3 reference standard.
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ISO 2469:2007(E)
The primary working standard should be checked against the control plate sufficiently often to ensure that any
change in the primary working standard is discovered before an error is introduced into the calibration.
6.4 Cleaning the non-fluorescent working standards
Follow the manufacturer's instructions. In the case of working standards of opal glass or ceramic material,
rinse with distilled water and detergent free from fluorescent ingredients while rubbing with a soft brush. Rinse
thoroughly in distilled water and dry in the air in a dust-free environment without allowing anything to touch the
surface. Leave it in a desiccator until it is optically stable.
7 Sampling
If the tests are being made to evaluate a lot, the sample should be selected in accordance with ISO 186. If the
tests are made on another type of sample, make sure that the test pieces taken are representative of the
sample received.
8 Preparation of the test pieces
Prepare the test pieces according to the instructions given in the relevant International Standard for the
determination of radiance factors or optical properties based on the measurement of radiance factors.
If it is desired simply to measure the radiance factor, rather than some other optical property defined by
another International Standard, follow the following procedure.
Avoiding watermarks, dirt and obvious defects, cut rectangular test pieces approximately 75 mm × 150 mm,
taking care to avoid touching the future test area.
If it is desired to measure the intrinsic radiance factor, assemble test pieces in a pad with their top sides
uppermost; the number should be such that doubling the number of test pieces does not alter the radiance
factor. Protect the pad by placing an additional sheet on both the top and bottom of the pad; avoid contamina-
tion and unnecessary exposure to light or heat. Mark the top test piece in one corner to identify the sample
and its top side.
NOTE If the top side can be distinguished from the wire side, it shall be uppermost; if not, as may be the case for
papers manufactured on double wire machines, ensure that the same side of the sheet is uppermost throughout the pad.
If sufficient sheets are not available or if it is desired to measure a background-dependent radiance factor,
select a suitable background and include a description of this background in the report.
9 Procedure
Determine the radiance factor as specified in the relevant International Standard for the determination of
radiance factors or optical properties based on the measurement of radiance factors.
If it is desired simply to measure the radiance factor, rather than some other optical property defined by
another International Standard, follow the following procedure.
9.1 Verification of calibration
Check the calibration of the instrument using a non-fluorescent working standard calibrated in relation to an
IR3 (5.3). Recalibrate the instrument if necessary.
NOTE If the instrument is of the spectrophotometer type, and if the material to be measured contains or is suspected
to contain a fluorescent component, the UV content of the illumination must be adjusted to match the desired illuminant
using the fluorescent (5.2) and non-fluorescent (see 5.2) ISO level 3 standards in an iterative procedure according to the
instrument maker's instructions. The procedure for UV-adjustment to match the CIE standard illuminant D65 is given in
ISO 11475 and for UV-adjustment to match the CIE illuminant C in ISO 2470.
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ISO 2469:2007(E)
9.2 Measurement
Remove the protecting sheets from the test piece pad. Without touching the test area, use the procedure
appropriate to the instrument, and the working standard, to measure the desired radiance factor. Read and
record the value to the nearest 0,01 percentage points or better.
10 Calculation and expression of results
Express the radiance factor results with the number of decimals appropriate to the uncertainty and
reproducibility of the procedure.
Calculate the results as required in the relevant International Standard for the determination of radiance
factors or optical properties based on the measurement of radiance factors, e.g.:
ISO 2470, Paper, board and pulps — Measurement of diffuse blue reflectance factor (ISO brightness)
ISO 2471, Paper and board — Determination of opacity (paper backing) — Diffuse reflectance method
ISO 5631, Paper and board — Determination of colour (C/2°) — Diffuse reflectance method
ISO 9416, Paper — Determination of light scattering and absorption coefficients (using Kubelka-Munk theory)
ISO 11475, Paper and board — Determination of CIE-whiteness, D65/10° (outdoor daylight)
ISO 11476, Paper and board — Determination of CIE-whiteness, C/2° (indoor illumination conditions)
NOTE Some informative comments on the definition and calculation of the measurement uncertainty are given in
Annex D.
11 Precision
Data relating to the precision of results obtained according to the procedure described in this International
Standard are given in the relevant test method for the determination of radiance factors or optical properties
based on the measurement of radiance factors. (See also Annex D).
12 Test report
Report the results as indicated in the relevant International Standard for the determination of radiance factors
or optical properties based on the measurement of radiance factors.
If a radiance factor is determined according to the procedure described in this International Standard, the test
report shall include the following details:
a) date and place of testing;
b) precise identification of the sample;
c) a reference to this International Standard;
d) the test results;
e) the wavelength range, pitch and bandwidth if a spectrophotometer is used, or the type of filter if a filter
instrument is used;
f) the illuminant to which the UV-content of the illumination is adjusted if a spectrophotometer is used;
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ISO 2469:2007(E)
g) the number of test pieces and the procedure adopted to calculate the reported results;
h) the type of instrument used;
i) any departure from this International Standard or any circumstances or influences that may have affected
the results.
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ISO 2469:2007(E)
Annex A
(normative)

Instruments for the measurement of radiance factor
The geometric, photometric and spectral characteristics of the instruments to which this International Standard
applies are defined as follows:
A.1 Geometric characteristics
A.1.1 The test piece and reference area shall be subjected to diffuse illumination which is achieved by
means of an integrating sphere (see Reference [2], 845.05.24) with an internal spectrally non-selective white
diffusing surface and an internal diameter of (150 ± 3) mm.
A.1.2 The sphere shall be constructed as a dual-beam instrument so that a measurement can be made on a
test piece, and a reference measurement can be made simultaneously on a reference region of the inner
surface of the sphere.
A.1.3 The sphere shall be constructed or equipped with screens (baffles) to ensure that neither the test
piece nor the reference region is directly illuminated by the light source.
A.1.4 The total area of the apertures and other non-reflecting areas in the sphere shall not exceed 13 % of
the area of the inner surface of the sphere.
A.1.5 The receptor aperture shall be surrounded by a black annulus subtending a half-angle of (15,8 ± 0,8)°
at the centre of the test piece aperture. This black annulus serves as a “gloss trap” so that specularly reflected
light from the test piece does not reach the receptor. The black annulus shall
...

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Papir, karton, lepenka in vlaknine - Merjenje faktorja razpršene odsevnostiPapier, carton et pâtes -- Mesurage du facteur de luminance énergétique diffusePaper, board and pulps -- Measurement of diffuse radiance factor85.060Papir, karton in lepenkaPaper and board85.040VlakninePulpsICS:Ta slovenski standard je istoveten z:ISO 2469:2007oSIST ISO 2469:2011en01-marec-2011oSIST ISO 2469:2011SLOVENSKI
STANDARD



oSIST ISO 2469:2011



Reference numberISO 2469:2007(E)© ISO 2007
INTERNATIONAL STANDARD ISO2469Fourth edition2007-06-15Paper, board and pulps — Measurement of diffuse radiance factor Papier, carton et pâtes — Mesurage du facteur de luminance énergétique diffuse
oSIST ISO 2469:2011



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© ISO 2007 – All rights reserved
oSIST ISO 2469:2011



ISO 2469:2007(E) © ISO 2007 – All rights reserved
iiiContents Page Foreword.iv Introduction.v 1 Scope.1 2 Normative references.1 3 Terms and definitions.1 4 Principle.3 5 Apparatus.3 6 Photometric calibration of the instrument and its working standards.4 7 Sampling.5 8 Preparation of the test pieces.5 9 Procedure.5 10 Calculation and expression of results.6 11 Precision.6 12 Test report.6 Annex A (normative)
Instruments for the measurement of radiance factor.8 Annex B (normative)
Calibration service — Photometric calibration.11 Annex C (normative)
Calibration service — UV-adjustment.13 Annex D (informative)
Measurement uncertainty.15 Annex E (informative)
Radiance and reflectance.18 Bibliography.19
oSIST ISO 2469:2011



ISO 2469:2007(E) iv
© ISO 2007 – All rights reserved Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 2469 was prepared by Technical Committee ISO/TC 6, Paper, board and pulps. This fourth edition of ISO 2469 cancels and replaces the third edition (ISO 2469:1994) and ISO 2469:1994/Cor.1:1998, which have been technically revised. Primarily, certain instrumental features and computational routines are more rigorously defined in order to meet the requirements of technological advances and in order to ensure a high precision and reproducibility in the measurement results. In addition, the property mentioned in the title has been changed from “diffuse reflectance factor” to “diffuse radiance factor” as an acknowledgement of the fact that many grades of paper now contain added fluorescent whitening agents. For any given material, the total radiance factor is the sum of the reflected radiance factor and the luminescent radiance factor, and it is this total property which is the subject of this International Standard. For pulps and papers not containing any fluorescent component, the radiance factor and the reflectance factor are synonymous, see Annex E. oSIST ISO 2469:2011



ISO 2469:2007(E) © ISO 2007 – All rights reserved
vIntroduction The radiance factor depends on the conditions of measurement, particularly the spectral and geometric characteristics of the instrument used. The diffuse radiance factor as defined by this International Standard is determined using instruments having the characteristics given in Annex A and calibrated according to the procedure specified in Annex B. The radiance factor is the sum of the reflected radiance factor and the luminescent radiance factors, and the radiance factor of a luminescent (fluorescent) object is dependent on the spectral power distribution of the illumination. The content of UV radiation in the illumination must therefore be set to a specified level if adequately accurate measurements are to be carried out on fluorescent objects. The preparation of fluorescent reference standards to enable this adjustment to be made is described in Annex C. The use of these fluorescent reference standards is described in detail in the International Standards describing the measurement of the properties of the materials containing fluorescent whitening agents. The spectral radiance factor or the weighted radiance factor applicable to one or several specified wavelength bands is often used to characterize the properties of pulp, paper and board. Examples of radiance factors associated with specified wavelength bands are the ISO brightness (diffuse blue radiance factor) and the luminance factor. The radiance factor or reflectance factor is also used as the basis for calculating optical properties, such as opacity, colour, whiteness and the Kubelka-Munk scattering and absorption coefficients. These various properties are specified in specific International Standards, for all of which this International Standard is the primary normative reference. oSIST ISO 2469:2011



oSIST ISO 2469:2011



INTERNATIONAL STANDARD ISO 2469:2007(E) © ISO 2007 – All rights reserved
1Paper, board and pulps — Measurement of diffuse radiance factor 1 Scope This International Standard describes the general procedure for measuring the diffuse radiance factor of all types of pulp, paper and board. More particularly, it specifies in detail in Annex A the characteristics of the equipment to be used for such measurements, and in Annex B the procedures to be used for calibrating that equipment. This International Standard may be used to measure the radiance factors and related properties of materials containing fluorescent whitening agents, provided that the UV radiation content in the illumination has been adjusted to the level specified in the specific International Standard describing the measurement of the property in question. This International Standard describes in Annex C the preparation of fluorescent reference standards, although the procedures for using these standards are not included, since their use is described in detail in the specific International Standards describing the measurement of the properties of materials containing fluorescent whitening agents. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 186, Paper and board — Sampling to determine average quality ISO 4094, Paper, board and pulps — International calibration of testing apparatus — Nomination and acceptance of standardizing and authorized laboratories ASTM E308-06, Standard Practice for Computing the Colors of Objects by Using the CIE System 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 radiance factor β ratio of the radiance of a surface element of a body in the direction delimited by a given cone with its apex at the surface element to that of the perfect reflecting diffuser under the same conditions of illumination NOTE For luminescent (fluorescent) materials, the total radiance factor, β, is the sum of two portions, the reflected radiance factor, βS, and the luminescent radiance factor, βL, so that: β = βS + βL For non-fluorescent materials, the reflected radiance factor, βS, is numerically equal to the reflectance factor, R. oSIST ISO 2469:2011



ISO 2469:2007(E) 2
© ISO 2007 – All rights reserved 3.2 diffuse radiance factor R ratio of the radiation reflected and emitted from a body to that reflected from the perfect reflecting diffuser under the same conditions of diffuse illumination and normal detection NOTE 1 The ratio is often expressed as a percentage. NOTE 2 This International Standard prescribes diffuse illumination and normal detection in an instrument constructed and calibrated in accordance with the provisions of this standard. 3.3 intrinsic radiance factor R∞ diffuse radiance factor of a layer or pad of material thick enough to be opaque, i.e., such that increasing the thickness of the pad by doubling the number of sheets results in no change in the measured radiance factor NOTE The radiance factor of a single non-opaque sheet is dependent on the background and is not a material property. 3.4 reflectance factor ratio of the radiation reflected by a surface element of a body in the direction delimited by a given cone with its apex at the surface element to that reflected by the perfect reflecting diffuser under the same conditions of illumination NOTE 1 The ratio is often expressed as a percentage. NOTE 2 This term may be used only when it is known that the test material exhibits no luminescence (fluorescence). 3.5 diffuse reflectance factor R ratio of the reflection from a body to that from the perfect reflecting diffuser under the same conditions of diffuse illumination and normal detection NOTE 1 The ratio is often expressed as a percentage. NOTE 2 This International Standard specifies diffuse illumination and normal detection in an instrument constructed and calibrated in accordance with the provisions of this standard. 3.6 intrinsic reflectance factor R∞ diffuse reflectance factor of a layer or pad of material thick enough to be opaque, i.e., such that increasing the thickness of the pad by doubling the number of sheets results in no change in the measured reflectance factor NOTE The reflectance factor of a single non-opaque sheet is dependent on the background and is not a material property. 3.7 ISO reference standard of level 1 IR1 the perfect reflecting diffuser (see CIE publication 17.4, No 845.04.54); an ideal spectrally uniform isotropic Lambertian diffuser with a reflectance equal to 1 at all wavelengths NOTE Reflectance is defined as the ratio of the reflected to the incident radiation, see Annex E. oSIST ISO 2469:2011



ISO 2469:2007(E) © ISO 2007 – All rights reserved
33.8 ISO reference standard of level 2 IR2 standard whose radiance factors have been determined by a standardizing laboratory in relation to the IR1 as defined by ISO 4094 NOTE This International Standard refers to two types of IR2. A non-fluorescent IR2 whose spectral reflectance factors have been determined by a standardizing laboratory in relation to the IR1. A non-fluorescent IR2 is used to calibrate the photometric scale of an authorized laboratory’s reference instrument. A fluorescent IR2 whose spectral radiance factors corresponding to a specified CIE illuminant have been determined by a standardizing laboratory. A fluorescent IR2 standard is used to adjust the UV level of an authorized laboratory’s reference instrument. 3.9 ISO reference standard of level 3 IR3 standard whose radiance factors have been determined by an authorized laboratory in relation to an IR2, as defined by ISO 4094 NOTE This International Standard refers to two types of IR3. A non-fluorescent IR3 whose spectral reflectance factors have been determined by an authorized laboratory in relation to the IR2. A non-fluorescent IR3 is used to calibrate the photometric scale of a testing laboratory’s reference instrument. A fluorescent IR3 whose calibration values have been determined an authorized laboratory in relation to the IR2. A testing laboratory uses a fluorescent IR3 to adjust the relative amount of UV radiation incident on the sample to a specified level. 4 Principle A test piece is irradiated diffusely in a standard instrument and the light reflected (and emitted as a result of fluorescence) in a direction normal to the surface is passed to a detection system. This detection system may consist either of a defined optical filter and photodetector or of an array of photodetectors where each detector responds to a specific effective wavelength. The desired radiance factors are determined directly from the output from the photodetector in the former case or by calculation from the detector array outputs using appropriate weighting functions in the latter case. 5 Apparatus 5.1 Reflectometer, having the geometric, spectral and photometric characteristics described in Annex A. 5.2 Reference standards for calibration of the instrument and the working standards, a non-fluorescent reference standard for photometric calibration of the instrument and its working standards, issued by an ISO/TC 6 authorized laboratory and fulfilling the requirements for an ISO reference standard of level 3 (see 3.9) as specified in Annex B. Use reference standards sufficiently frequently to ensure satisfactory calibration. NOTE If fluorescent materials are to be measured, a fluorescent reference standard issued by an ISO/TC 6 authorized laboratory is required to enable the UV-content of the illumination to be adjusted to correspond to the appropriate CIE illuminant, as specified in Annex C. The use of these fluorescent reference standards is described in the International Standards concerned. 5.3 Two non-fluorescent working standards, of opal glass, ceramic or other suitable material with flat surfaces. NOTE In some instruments, the function of the primary working standard (see 6.3) may be fulfilled by a built-in internal standard. oSIST ISO 2469:2011



ISO 2469:2007(E) 4
© ISO 2007 – All rights reserved For measurements on fluorescent materials, which require a fluorescent reference standard (see 5.2) to enable the UV-content of the illumination to be adjusted, stable fluorescent working standards of plastic or other material incorporating a fluorescent whitening agent are required. These working standards are described in the relevant International Standards. 5.4 Black cavity, for calibration or validation of the low end of the photometric scale. This black cavity shall have a radiance factor which does not differ from its nominal value by more than 0,2 percentage points at all wavelengths. The black cavity should be stored upside-down in a dust-free environment or with a protective cover. During calibration, the instrument shall be adjusted to the nominal value of the black cavity. It is not yet possible to institute a system of reference standards to enable testing laboratories to check the reflectance factor of the black cavity. At the time of delivery, the level should be guaranteed by the instrument maker. Questions concerning the use and condition of the black cavity should be resolved by contacting the instrument maker. 6 Photometric calibration of the instrument and its working standards 6.1 Calibration of the instrument Using the procedure appropriate to the instrument, calibrate the instrument with an IR3. Make a measurement on the IR3 in order to check that the calibration is satisfactory. The deviation between the measured and the assigned brightness and/or tristimulus values of the IR3 used for the primary calibration should not exceed 0,05 percentage points. NOTE Although barium sulfate powders for pressing tablets are commercially available for which the absolute spectral radiance factors are given on the container, these values are not considered to be traceable according to the principles of modern metrology, and tablets based on barium sulfate powder are not considered to be suitable for use as an IR3 as required by this International Standard. All calibrations are thus related to the IR1 through a calibration chain comprising an IR2 and an IR3 to which absolute values have been assigned respectively by a standardizing laboratory and by an authorized laboratory using an instrument conforming to this International Standard. Handle each IR3 carefully and protect the test area from contamination. Store it in darkness, when not in use. 6.2 Calibration of the non-fluorescent working standards The non-fluorescent working standards shall be calibrated against ISO reference standards of level 3 in the instrument in which they are to be used. Using the procedure appropriate to the instrument, calibrate the instrument with an IR3. Clean the working standards (see 6.4), measure the working standards and read off and record to the nearest 0,01 percentage point the radiance factors of the cleaned working standards. NOTE In order to achieve agreement with the reference instrument, a working standard may be assigned multiple values, depending upon the working level and the purpose of the measurement. This applies if the working standard is translucent or glossy and if the linearity of the instrument scale is poor. 6.3 Use of non-fluorescent working standards Use one plate as a primary working standard for checking and calibrating the instrument, and use the other much less frequently as a control plate for checking the primary working standard. The frequency with which the instrument needs to be calibrated depends on the type of instrument. Frequent calibration of the instrument tends to introduce undesirable fluctuations in the instrument, and the instrument should be recalibrated only when a check with the primary working standard indicates that calibration is necessary. Check the primary working standard periodically against the control plate. If any change in the radiance factor is noticed, clean the primary working standard by the procedure described in 6.4. If the change persists, clean and recalibrate both working standards against an appropriate IR3 reference standard. oSIST ISO 2469:2011



ISO 2469:2007(E) © ISO 2007 – All rights reserved
5The primary working standard should be checked against the control plate sufficiently often to ensure that any change in the primary working standard is discovered before an error is introduced into the calibration. 6.4 Cleaning the non-fluorescent working standards Follow the manufacturer's instructions. In the case of working standards of opal glass or ceramic material, rinse with distilled water and detergent free from fluorescent ingredients while rubbing with a soft brush. Rinse thoroughly in distilled water and dry in the air in a dust-free environment without allowing anything to touch the surface. Leave it in a desiccator until it is optically stable. 7 Sampling If the tests are being made to evaluate a lot, the sample should be selected in accordance with ISO 186. If the tests are made on another type of sample, make sure that the test pieces taken are representative of the sample received. 8 Preparation of the test pieces Prepare the test pieces according to the instructions given in the relevant International Standard for the determination of radiance factors or optical properties based on the measurement of radiance factors. If it is desired simply to measure the radiance factor, rather than some other optical property defined by another International Standard, follow the following procedure. Avoiding watermarks, dirt and obvious defects, cut rectangular test pieces approximately 75 mm × 150 mm, taking care to avoid touching the future test area. If it is desired to measure the intrinsic radiance factor, assemble test pieces in a pad with their top sides uppermost; the number should be such that doubling the number of test pieces does not alter the radiance factor. Protect the pad by placing an additional sheet on both the top and bottom of the pad; avoid contamina-tion and unnecessary exposure to light or heat. Mark the top test piece in one corner to identify the sample and its top side. NOTE If the top side can be distinguished from the wire side, it shall be uppermost; if not, as may be the case for papers manufactured on double wire machines, ensure that the same side of the sheet is uppermost throughout the pad. If sufficient sheets are not available or if it is desired to measure a background-dependent radiance factor, select a suitable background and include a description of this background in the report. 9 Procedure Determine the radiance factor as specified in the relevant International Standard for the determination of radiance factors or optical properties based on the measurement of radiance factors. If it is desired simply to measure the radiance factor, rather than some other optical property defined by another International Standard, follow the following procedure. 9.1 Verification of calibration Check the calibration of the instrument using a non-fluorescent working standard calibrated in relation to an IR3 (5.3). Recalibrate the instrument if necessary. NOTE If the instrument is of the spectrophotometer type, and if the material to be measured contains or is suspected to contain a fluorescent component, the UV content of the illumination must be adjusted to match the desired illuminant using the fluorescent (5.2) and non-fluorescent (see 5.2) ISO level 3 standards in an iterative procedure according to the instrument maker's instructions. The procedure for UV-adjustment to match the CIE standard illuminant D65 is given in ISO 11475 and for UV-adjustment to match the CIE illuminant C in ISO 2470. oSIST ISO 2469:2011



ISO 2469:2007(E) 6
© ISO 2007 – All rights reserved 9.2 Measurement Remove the protecting sheets from the test piece pad. Without touching the test area, use the procedure appropriate to the instrument, and the working standard, to measure the desired radiance factor. Read and record the value to the nearest 0,01 percentage points or better. 10 Calculation and expression of results Express the radiance factor results with the number of decimals appropriate to the uncertainty and reproducibility of the procedure. Calculate the results as required in the relevant International Standard for the determination of radiance factors or optical properties based on the measurement of radiance factors, e.g.: ISO 2470, Paper, board and pulps — Measurement of diffuse blue reflectance factor (ISO brightness) ISO 2471, Paper and board — Determination of opacity (paper backing) — Diffuse reflectance method ISO 5631, Paper and board — Determination of colour (C/2°) — Diffuse reflectance method ISO 9416, Paper — Determination of light scattering and absorption coefficients (using Kubelka-Munk theory) ISO 11475, Paper and board — Determination of CIE-whiteness, D65/10° (outdoor daylight) ISO 11476, Paper and board — Determination of CIE-whiteness, C/2° (indoor illumination conditions) NOTE Some informative comments on the definition and calculation of the measurement uncertainty are given in Annex D. 11 Precision Data relating to the precision of results obtained according to the procedure described in this International Standard are given in the relevant test method for the determination of radiance factors or optical properties based on the measurement of radiance factors. (See also Annex D). 12 Test report Report the results as indicated in the relevant International Standard for the determination of radiance factors or optical properties based on the measurement of radiance factors. If a radiance factor is determined according to the procedure described in this International Standard, the test report shall include the following details: a) date and place of testing; b) precise identification of the sample; c) a reference to this International Standard; d) the test results; e) the wavelength range, pitch and bandwidth if a spectrophotometer is used, or the type of filter if a filter instrument is used; f) the illuminant to which the UV-content of the illumination is adjusted if a spectrophotometer is used; oSIST ISO 2469:2011



ISO 2469:2007(E) © ISO 2007 – All rights reserved
7g) the number of test pieces and the procedure adopted to calculate the reported results; h) the type of instrument used; i) any departure from this International Standard or any circumstances or influences that may have affected the results. oSIST ISO 2469:2011



ISO 2469:2007(E) 8
© ISO 2007 – All rights reserved Annex A (normative)
Instruments for the measurement of radiance factor The geometric, photometric and spectral characteristics of the instruments to which this International Standard applies are defined as follows: A.1 Geometric characteristics A.1.1 The test piece and reference area shall be subjected to diffuse illumination which is achieved by means of an integrating sphere (see Reference [2], 845.05.24) with an internal spectrally non-selective white diffusing surface and an internal diameter of (150 ± 3) mm. A.1.2 The sphere shall be constructed as a dual-beam instrument so that a measurement can be made on a test piece, and a reference measurement can be made simultaneously on a reference region of the inner surface of the sphere. A.1.3 The sphere shall be constructed or equipped with screens (baffles) to ensure that neither the test piece nor the reference region is directly illuminated by the light source. A.1.4 The total area of the apertures and other non-reflecting areas in the sphere shall not exceed 13 % of the area of the inner surface of the sphere. A.1.5 The receptor aperture shall be surrounded by a black annulus subtending a half-angle of (15,8 ± 0,8)° at the centre of the test piece aperture. This black annulus serves as a “gloss trap” so that specularly reflected light from the test piece does not reach the receptor. The black annulus shall be matt and shall have a radiance factor of less than 4 %, at all wavelengths within the visible region. A.1.6 The test piece aperture shall be designed so that the test piece itself is essentially a continuation of the internal wall of the sphere. The rim of the test piece aperture sha
...

NORME ISO
INTERNATIONALE 2469
Quatrième édition
2007-06-15


Papier, carton et pâtes — Mesurage du
facteur de luminance énergétique diffuse
Paper, board and pulps — Measurement of diffuse radiance factor




Numéro de référence
ISO 2469:2007(F)
©
ISO 2007

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ISO 2469:2007(F)
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ii © ISO 2007 – Tous droits réservés

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ISO 2469:2007(F)
Sommaire Page
Avant-propos. iv
Introduction . v
1 Domaine d'application. 1
2 Références normatives . 1
3 Termes et définitions. 1
4 Principe. 3
5 Appareillage . 4
6 Étalonnage photométrique de l'appareil et des étalons de travail . 4
7 Échantillonnage . 5
8 Préparation des éprouvettes . 5
9 Mode opératoire . 6
10 Calcul et expression des résultats. 6
11 Fidélité . 7
12 Rapport d'essai . 7
Annexe A (normative) Appareils pour le mesurage du facteur de luminance énergétique . 8
Annexe B (normative) Service d'étalonnage — Étalonnage photométrique . 11
Annexe C (normative) Service d'étalonnage — Réglage de la teneur en UV. 13
Annexe D (informative) Incertitude de mesure. 15
Annexe E (informative) Luminance énergétique et réflectance. 19
Bibliographie . 20

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ISO 2469:2007(F)
Avant-propos
L'ISO (Organisation internationale de normalisation) est une fédération mondiale d'organismes nationaux de
normalisation (comités membres de l'ISO). L'élaboration des Normes internationales est en général confiée
aux comités techniques de l'ISO. Chaque comité membre intéressé par une étude a le droit de faire partie du
comité technique créé à cet effet. Les organisations internationales, gouvernementales et non
gouvernementales, en liaison avec l'ISO participent également aux travaux. L'ISO collabore étroitement avec
la Commission électrotechnique internationale (CEI) en ce qui concerne la normalisation électrotechnique.
Les Normes internationales sont rédigées conformément aux règles données dans les Directives ISO/CEI,
Partie 2.
La tâche principale des comités techniques est d'élaborer les Normes internationales. Les projets de Normes
internationales adoptés par les comités techniques sont soumis aux comités membres pour vote. Leur
publication comme Normes internationales requiert l'approbation de 75 % au moins des comités membres
votants.
L'attention est appelée sur le fait que certains des éléments du présent document peuvent faire l'objet de
droits de propriété intellectuelle ou de droits analogues. L'ISO ne saurait être tenue pour responsable de ne
pas avoir identifié de tels droits de propriété et averti de leur existence.
L'ISO 2469 a été élaborée par le comité technique ISO/TC 6, Papiers, carton et pâtes.
Cette quatrième édition de l'ISO 2469 annule et remplace la troisième édition (ISO 2469:1994) ainsi que
l’ISO 2496:1994/Cor.1:1998, qui ont fait l'objet d'une révision technique. Certaines caractéristiques
instrumentales et programmes de calcul sont définis de manière plus rigoureuse afin de répondre aux
exigences des avancées technologiques et de garantir une haute fidélité et reproductibilité des résultats de
mesurage.
En outre, la propriété «facteur de réflectance diffuse» mentionnée dans le titre a été remplacée par le «facteur
de luminance énergétique diffuse» pour tenir compte du fait que de nombreuses catégories de papier
contiennent aujourd'hui des agents d'azurage fluorescents. Pour tout matériau donné, le facteur de luminance
énergétique totale correspond à la somme du facteur de luminance énergétique réfléchie et du facteur de
luminance énergétique luminescente. C'est sur cette propriété totale que porte précisément la présente
Norme internationale. Pour les pâtes et papiers ne contenant pas de composante fluorescente, le facteur de
luminance énergétique et le facteur de réflectance sont synonymes, voir l'Annexe E.
iv © ISO 2007 – Tous droits réservés

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ISO 2469:2007(F)
Introduction
Le facteur de luminance énergétique dépend des conditions de mesurage, en particulier des caractéristiques
spectrales et géométriques de l'appareil utilisé. Le facteur de luminance énergétique diffuse, tel que défini par
la présente Norme internationale, est déterminé en utilisant des appareils présentant les caractéristiques
fournies à l'Annexe A et étalonnés conformément au mode opératoire spécifié à l'Annexe B.
Le facteur de luminance énergétique est la somme du facteur de luminance énergétique réfléchie et des
facteurs de luminance énergétique luminescente, et le facteur de luminance énergétique d'un objet
luminescent (fluorescent) dépend de la répartition de la puissance spectrale de l'éclairage. Pour effectuer des
mesurages avec une précision appropriée sur des objets fluorescents, la teneur en rayonnements UV de
l'éclairage doit donc être réglée à un niveau spécifié. La préparation des étalons de référence fluorescents
permettant de réaliser ce réglage est décrite à l'Annexe C. L'utilisation de ces étalons de référence
fluorescents est présentée de manière détaillée dans les Normes internationales décrivant le mesurage des
propriétés de matériaux contenant des agents d'azurage fluorescents.
Le facteur de luminance énergétique spectrale ou le facteur de luminance énergétique pondérée applicable à
une ou plusieurs bandes de longueur d'onde spécifiées est souvent utilisé pour caractériser les propriétés de
la pâte, du papier et du carton. Le degré de blancheur ISO (facteur de luminance énergétique diffuse dans le
bleu) et le facteur de luminance sont des exemples de facteurs de luminance énergétique associés à des
bandes de longueur d'onde spécifiées.
Le facteur de luminance énergétique ou le facteur de réflectance est également utilisé pour calculer des
propriétés optiques telles que l'opacité, la couleur, la blancheur et les coefficients de diffusion et d'absorption
de Kubelka-Munk. Ces différentes propriétés sont spécifiées dans les Normes internationales spécifiques,
pour lesquelles la présente Norme internationale constitue la principale référence normative.

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NORME INTERNATIONALE ISO 2469:2007(F)

Papier, carton et pâtes — Mesurage du facteur de luminance
énergétique diffuse
1 Domaine d'application
La présente Norme internationale décrit le mode opératoire général utilisé pour mesurer le facteur de
luminance énergétique diffuse de tous les types de pâte, papier et carton. Elle spécifie notamment de manière
détaillée les caractéristiques des appareils à utiliser pour effectuer ces mesurages, à l'Annexe A, et les modes
opératoires à suivre pour étalonner ces appareils, à l'Annexe B.
La présente Norme internationale peut être utilisée pour mesurer les facteurs de luminance énergétique et
des propriétés connexes des matériaux contenant des agents d'azurage fluorescents à condition que la
teneur en rayonnements UV dans l'éclairement ait été réglée au niveau spécifié dans la Norme internationale
spécifique décrivant le mesurage de la propriété considérée.
La présente Norme internationale décrit le mode de préparation pour les étalons de référence fluorescents à
l'Annexe C mais ne fournit pas de mode opératoire d'utilisation de ces étalons de référence dans la mesure où
celui-ci fait l'objet d'une description détaillée dans les Normes internationales spécifiques décrivant le mesurage
des propriétés de matériaux contenant des agents d'azurage fluorescents.
2 Références normatives
Les documents de référence suivants sont indispensables pour l'application du présent document. Pour les
références datées, seule l'édition citée s'applique. Pour les références non datées, la dernière édition du
document de référence s'applique (y compris les éventuels amendements).
ISO 186, Papier et carton — Échantillonnage pour déterminer la qualité moyenne
ISO 4094, Papiers, cartons et pâtes — Étalonnage international des appareils d'essai — Désignation et
agrément des laboratoires de référence et des laboratoires agréés
ASTM E 308-06, Standard Practice for Computing the Colors of Objects by Using the CIE System
3 Termes et définitions
Pour les besoins du présent document, les termes et définitions suivants s'appliquent.
3.1
facteur de luminance énergétique
β
rapport de la luminance énergétique de l'élément de surface d'un corps dans la direction délimitée par un
cône donné dont le sommet se trouve au niveau de l'élément de surface à la luminance énergétique du
diffuseur parfait par réflexion dans les mêmes conditions d'éclairage
© ISO 2007 – Tous droits réservés 1

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ISO 2469:2007(F)
NOTE Pour les matériaux luminescents (fluorescents), le facteur de luminance énergétique totale, β, est la somme
de deux grandeurs: le facteur de luminance énergétique réfléchie, β , et le facteur de luminance énergétique
S
luminescente, β , de sorte que:
L
β = β + β
S L
Pour les matériaux non fluorescents, la valeur du facteur de luminance énergétique réfléchie, β , est numériquement
S
égale au facteur de réflectance, R.
3.2
facteur de luminance énergétique diffuse
R
rapport du rayonnement réfléchi et émis par un corps au rayonnement réfléchi par le diffuseur parfait par
réflexion dans les mêmes conditions d'éclairage diffus et de détection normale
NOTE 1 Ce rapport est souvent exprimé en pourcentage.
NOTE 2 La présente Norme internationale spécifie l'utilisation d'un éclairage diffus et d'une détection normale dans un
appareil construit et étalonné conformément aux dispositions de cette norme.
3.3
facteur de luminance énergétique intrinsèque
R
∞
facteur de luminance énergétique diffuse d'une couche de matériau ou d'une liasse suffisamment épaisse
pour être opaque, c'est-à-dire que l'augmentation de l'épaisseur de la liasse, en doublant le nombre de
feuilles la constituant, n'engendre aucune modification du facteur de luminance énergétique mesuré
NOTE Le facteur de luminance énergétique d'une feuille unique non opaque dépend du fond et n'est pas une
propriété du matériau.
3.4
facteur de réflectance
rapport du rayonnement réfléchi par un élément de surface d'un corps dans la direction délimitée par un cône
donné dont le sommet se trouve au niveau de l'élément de surface au rayonnement réfléchi par le diffuseur
parfait par réflexion dans les mêmes conditions d'éclairage
NOTE 1 Ce rapport est souvent exprimé en pourcentage.
NOTE 2 Ce terme ne peut être utilisé que s'il s'avère que le matériau d'essai ne présente aucune luminescence
(fluorescence).
3.5
facteur de réflectance diffuse
R
rapport de la réflexion d'un corps à la réflexion du diffuseur parfait par réflexion dans les mêmes conditions
d'éclairage diffus et de détection normale
NOTE 1 Ce rapport est souvent exprimé en pourcentage.
NOTE 2 La présente Norme internationale spécifie l'utilisation d'un éclairage diffus et d'une détection normale dans un
appareil construit et étalonné conformément aux dispositions de cette norme.
3.6
facteur de réflectance intrinsèque
R
∞
facteur de réflectance diffuse d'une couche de matériau ou d'une liasse suffisamment épaisse pour être
opaque, c'est-à-dire que l'augmentation de l'épaisseur de la liasse, en doublant le nombre de feuilles la
constituant, n'engendre aucune modification du facteur de réflectance mesuré
NOTE Le facteur de réflectance d'une feuille unique non opaque dépend du fond et n'est pas une propriété du
matériau.
2 © ISO 2007 – Tous droits réservés

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ISO 2469:2007(F)
3.7
étalon de référence ISO de niveau 1
IR1
diffuseur parfait par réflexion (voir Référence [2], 845.04.54); diffuseur Lambertien isotrope idéal
spectralement uniforme dont la réflectance est égale à 1 pour toutes les longueurs d'onde
NOTE La réflectance est définie comme le rapport du rayonnement réfléchi au rayonnement incident, voir l'Annexe E.
3.8
étalon de référence ISO de niveau 2
IR2
étalon de référence dont les facteurs de luminance énergétique ont fait l'objet d'une détermination par un
laboratoire d'étalonnage par rapport à l'IR1, tel que défini dans l'ISO 4094
NOTE La présente Norme internationale fait référence à deux types d'IR2.
Un IR2 non fluorescent dont les facteurs de réflectance spectrale ont été déterminés par un laboratoire d'étalonnage par
rapport à l'IR1. Un IR2 non fluorescent est utilisé pour étalonner l'échelle photométrique d'un appareil de référence de
laboratoire agréé.
Un IR2 fluorescent dont les facteurs de luminance énergétique spectrale correspondant à un illuminant CIE spécifié ont
été déterminés par un laboratoire d'étalonnage. Un étalon IR2 fluorescent est utilisé pour régler la teneur en UV d'un
appareil de référence de laboratoire agréé.
3.9
étalon de référence ISO de niveau 3
IR3
étalon de référence dont les facteurs de luminance énergétique ont fait l'objet d'une détermination par un
laboratoire agréé par rapport à un IR2, tel que défini dans l'ISO 4094
NOTE La présente Norme internationale fait référence à deux types d'IR3.
Un IR3 non fluorescent dont les facteurs de réflectance spectrale ont été déterminés par un laboratoire agréé par rapport
à l'IR2. Un IR3 non fluorescent est utilisé pour étalonner l'échelle photométrique d'un appareil de référence de laboratoire
d'essai.
Un IR3 non fluorescent dont les valeurs d'étalonnage ont été déterminées par un laboratoire agréé par rapport à l'IR2. Un
laboratoire d'essais utilise un IR3 fluorescent pour régler la quantité relative du rayonnement UV incident sur l'échantillon
à un niveau spécifié.
4 Principe
Une éprouvette est irradiée de manière diffuse dans un instrument étalon et la lumière réfléchie (et émise par
fluorescence) dans une direction normale à la surface est envoyée vers un système de détection. Ce système
de détection peut être constitué d'un filtre optique déterminé et d'un photodétecteur ou d'un réseau de
photodétecteurs dans lequel chaque détecteur correspond à une longueur d'onde efficace spécifique. Dans le
premier cas, les facteurs de luminance énergétique recherchés sont déterminés directement à partir des
données de sortie du photodétecteur et, dans le deuxième cas, ils sont calculés à partir des données de sortie
du réseau de détecteurs au moyen des fonctions de pondération appropriées.
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ISO 2469:2007(F)
5 Appareillage
5.1 Réflectomètre, ayant les caractéristiques du point de vue géométrique, spectral et photométrique
décrites à l'Annexe A.
5.2 Étalons de référence pour l'étalonnage de l'appareil et des étalons de travail, un étalon
non fluorescent pour l'étalonnage photométrique de l'appareil et des étalons de travail, provenant d'un
laboratoire agréé par l'ISO/TC 6 et satisfaisant aux exigences d'un étalon de référence ISO de niveau 3 (voir
3.9), tel que spécifié à l'Annexe B.
Utiliser des étalons de référence de manière suffisamment fréquente pour garantir un étalonnage satisfaisant.
NOTE Si des matériaux fluorescents doivent être mesurés, un étalon de référence fluorescent provenant d'un
laboratoire agréé par l'ISO/TC 6 est requis afin de pouvoir régler la teneur en UV de l'éclairement pour qu'elle corresponde
à l'illuminant CIE approprié, tel que spécifié à l'Annexe C. L'utilisation de ces étalons de référence fluorescents est décrite
dans les Normes internationales y afférentes.
5.3 Deux étalons de travail non fluorescents, sous forme de deux plaques de verre opale, de céramique
ou d'un autre matériau adapté de surface plane.
NOTE Dans certains appareils, la fonction de l'étalon de travail primaire (voir 6.3) peut être remplie par un étalon
interne intégré.
Pour les mesurages sur des matériaux fluorescents nécessitant un étalon de référence fluorescent (voir 5.2)
afin de pouvoir régler la teneur en UV de l'éclairement, des étalons de travail fluorescents stables en plastique
ou d'un autre matériau incorporant un agent d'azurage fluorescent sont requis. Ces étalons de travail sont
décrits dans les Normes internationales applicables.
5.4 Corps noir, pour l'étalonnage ou la validation du bas de l'échelle photométrique. Le facteur de
luminance énergétique de ce corps noir ne doit pas varier de sa valeur nominale de plus de 0,2 %, et ce à
toutes les longueurs d'onde. Il convient de stocker le corps noir la tête en bas dans un environnement exempt
de poussière ou de le recouvrir d'un couvercle de protection. Pendant l'étalonnage, l'appareil doit être réglé à
la valeur nominale du corps noir.
Il n'est toutefois pas encore possible de mettre en place un système d'étalons de référence permettant aux
laboratoires d'essai de vérifier le facteur de réflectance du corps noir. Au moment de la livraison, il convient
que le niveau soit garanti par le fabricant de l'appareil. Pour toute question relative à l'utilisation et à l'état du
corps noir, il convient de s'adresser au fabricant de l'appareil.
6 Étalonnage photométrique de l'appareil et des étalons de travail
6.1 Étalonnage de l'appareil
À l'aide du mode opératoire approprié, étalonner l'appareil avec un IR3. Procéder à un mesurage sur l'IR3 afin
de vérifier que l'étalonnage est satisfaisant. Il convient que l'écart entre le degré de blancheur mesuré et le
degré de blancheur assigné et/ou les composantes trichromatiques de l'IR3 utilisées pour l'étalonnage
primaire n'excède pas 0,05 %.
NOTE De la poudre de sulfate de baryum est disponible dans le commerce pour réaliser des tablettes comprimées
dont les facteurs de luminance énergétique spectrale absolue figurent sur le flacon, mais ces valeurs ne sont pas
considérées traçables selon les principes de métrologie moderne, et les tablettes de sulfate de baryum ne sont pas
considérées adaptées pour être utilisées en tant qu'IR3, tel que requis par la présente Norme internationale.
Tous les étalonnages sont ainsi reliés à un IR1 par une chaîne d'étalonnage comprenant un IR2 et un IR3
auxquels des valeurs absolues sont assignées respectivement par un laboratoire d'étalonnage et un
laboratoire agréé utilisant un appareil conforme à la présente Norme internationale.
Manipuler les IR3 avec précaution et protéger la surface d'essai contre toute contamination. En cas de
non-utilisation, conserver les IR3 dans l'obscurité.
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ISO 2469:2007(F)
6.2 Étalonnage des étalons de travail non fluorescents
Les étalons de travail non fluorescents doivent être étalonnés par rapport à des étalons de référence ISO de
niveau 3 dans l'appareil dans lequel ils seront utilisés.
À l'aide du mode opératoire approprié, étalonner l'appareil avec un IR3. Nettoyer les étalons de travail
(voir 6.4), mesurer les étalons de travail, relever et noter à 0,01 % près les facteurs de luminance énergétique
des étalons de travail préalablement nettoyés.
NOTE Afin qu'il y ait conformité avec l'appareil de référence, des valeurs multiples peuvent être attribuées à un
étalon de travail selon le niveau de travail et de l'objectif du mesurage. Cela s'applique si l'étalon de travail est translucide
ou brillant et si la linéarité de l'échelle de l'appareil est faible.
6.3 Utilisation d'étalons de travail non fluorescents
Utiliser une plaque comme étalon de travail primaire pour la vérification et l'étalonnage de l'appareil et utiliser
l'autre plaque bien moins fréquemment, comme plaque de contrôle, pour la vérification de l'étalon de travail
primaire. La fréquence avec laquelle l'appareil doit être étalonné est fonction du type d'appareil. L'étalonnage
fréquent de l'appareil tend à introduire des fluctuations non souhaitées de l'appareil. Il convient de ne
réétalonner l'appareil que lorsqu'une vérification au moyen de l'étalon de travail primaire indique que
l'étalonnage est nécessaire. Vérifier périodiquement l'étalon de travail primaire par rapport à la plaque de
contrôle. S'il y a un changement quelconque du facteur de luminance énergétique, nettoyer l'étalon de travail
primaire au moyen du mode opératoire décrit en 6.4. Si cette modification persiste, nettoyer et réétalonner les
deux étalons de travail par rapport à un étalon IR3 approprié.
Il convient que l'étalon de travail primaire soit vérifié au moyen de la plaque de contrôle suffisamment souvent
pour s'assurer que toute modification éventuelle de l'étalon de travail primaire soit décelée avant l'étalonnage.
6.4 Nettoyage des étalons de travail non fluorescents
Suivre les instructions du fabricant. Si les étalons de travail sont en verre opale ou en céramique, rincer la
plaque avec de l'eau distillée et du détergent exempt de matières fluorescentes et nettoyer en utilisant une
brosse douce. Rincer soigneusement dans de l'eau distillée et laisser sécher à l'air dans un environnement
exempt de poussière et sans rien laisser entrer en contact avec la surface. Laisser la plaque dans un
dessiccateur jusqu'à ce qu'elle soit stable du point de vue optique.
7 Échantillonnage
Si les essais sont réalisés pour évaluer un lot, il convient de sélectionner l'échantillon conformément à
l'ISO 186. Si les essais sont effectués sur un autre type d'échantillon, veiller à ce que les éprouvettes
sélectionnées soient représentatives de l'échantillon reçu.
8 Préparation des éprouvettes
Préparer les éprouvettes conformément aux instructions fournies dans la Norme internationale applicable à la
détermination des facteurs de luminance énergétique ou des propriétés optiques basés sur le mesurage des
facteurs de luminance énergétique.
Pour mesurer simplement le facteur de luminance énergétique, plutôt qu'une autre propriété optique définie
dans une autre Norme internationale, suivre le mode opératoire suivant:
Couper des éprouvettes rectangulaires d'environ 75 mm × 150 mm, en évitant les filigranes, les impuretés et
les défauts visibles et en veillant à ne pas toucher la surface d'essai considérée.
Pour mesurer le facteur de luminance énergétique intrinsèque, assembler les éprouvettes en une liasse, en
plaçant les faces supérieures sur le dessus; il convient que le fait de doubler le nombre d'éprouvettes n'altère
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ISO 2469:2007(F)
pas le facteur de luminance énergétique. Protéger la liasse en plaçant une feuille supplémentaire sur le
dessus et en dessous; éviter toute contamination et exposition inutile à la lumière ou à la chaleur. Marquer
l'éprouvette du dessus dans un coin afin d'identifier l'échantillon et sa face supérieure.
NOTE Lorsqu'il est possible de distinguer la face supérieure de la face toile, celle-ci doit être placée sur le dessus;
dans le cas contraire, par exemple pour les papiers fabriqués sur des machines à double toile, veiller à ce que la même
face de la feuille soit toujours sur le dessus dans l'ensemble de la liasse.
Si le nombre de feuilles n'est pas suffisant, ou pour mesurer un facteur de luminance énergétique dépendant
du fond, sélectionner un fond adapté et joindre une description de ce fond dans le rapport.
9 Mode opératoire
Déterminer le facteur de luminance énergétique tel que spécifié dans la Norme internationale applicable à la
détermination des facteurs de luminance énergétique ou des propriétés optiques basés sur le mesurage des
facteurs de luminance énergétique.
Pour mesurer simplement le facteur de luminance énergétique, plutôt qu'une autre propriété optique définie
dans une autre Norme internationale, suivre le mode opératoire suivant.
9.1 Vérification de l'étalonnage
Vérifier l'étalonnage de l'appareil en utilisant un étalon de travail non fluorescent étalonné par rapport à un IR3
(5.3). Réétalonner l'appareil si nécessaire.
NOTE Si l'appareil est de type spectrophotomètre, et si le matériau à mesurer contient ou est susceptible de contenir
une composante fluorescente, la teneur en UV de l'éclairement doit être réglée de manière à correspondre à l'illuminant
considéré, en utilisant des étalons ISO de niveau 3 fluorescents (5.2) et non fluorescents (voir 5.2) selon un mode
opératoire itératif et en observant les instructions du fabricant de l'appareil. Le mode opératoire permettant de régler la
teneur en UV pour qu'elle corresponde à un illuminant normalisé CIE est fourni dans l'ISO 11475 (illuminant D65) ou dans
l'ISO 2470 (illuminant C).
9.2 Mesurage
Enlever les feuilles de protection de la liasse d'éprouvettes. Sans toucher la surface d'essai, utiliser le mode
opératoire adapté à l'appareil, ainsi que l'étalon de travail, pour mesurer le facteur de luminance énergétique
recherché. Relever et noter la valeur à 0,01 % près ou mieux.
10 Calcul et expression des résultats
Exprimer les résultats du facteur de luminance énergétique avec le nombre de décimales adapté à
l'incertitude et à la reproductibilité du mode opératoire.
Calculer les résultats tel que requis dans la Norme internationale applicable à la détermination des facteurs de
luminance énergétique ou des propriétés optiques basés sur le mesurage des facteurs de luminance
énergétique, par exemple:
ISO 2470, Papier, carton et pâtes — Mesurage du facteur de réflectance diffuse dans le bleu (degré de
blancheur ISO)
ISO 2471, Papier et carton — Détermination de l'opacité sur fond papier — Méthode de réflexion en lumière
diffuse
ISO 5631, Papier et carton — Détermination de la couleur (C/2°) — Méthode par réflectance diffuse
ISO 9416, Papier — Détermination des coefficients de diffusion et d'absorption de la lumière (utilisation de la
théorie de Kubelka-Munk)
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ISO 2469:2007(F)
ISO 11475, Papier et carton — Déterminati
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