SIST ISO 11475:2018

SLOVENSKI STANDARD
SIST ISO 11475:2018
01-oktober-2018
1DGRPHãþD
SIST ISO 11475:2011
3DSLUNDUWRQLQOHSHQND'RORþDQMHEHOLQHSR&,('ƒ]XQDQMDGQHYQD
VYHWORED
Paper and board -- Determination of CIE whiteness, D65/10 degrees (outdoor daylight)
Papier et carton -- Détermination du degré de blanc CIE, D65/10 degrés (lumière du jour
extérieure)
Ta slovenski standard je istoveten z: ISO 11475:2017
ICS:
85.060 Papir, karton in lepenka Paper and board
SIST ISO 11475:2018 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST ISO 11475:2018

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SIST ISO 11475:2018
INTERNATIONAL ISO
STANDARD 11475
Third edition
2017-05
Paper and board — Determination
of CIE whiteness, D65/10° (outdoor
daylight)
Papier et carton — Détermination du degré de blanc CIE, D65/10°
(lumière du jour extérieure)
Reference number
ISO 11475:2017(E)
©
ISO 2017

---------------------- Page: 3 ----------------------

SIST ISO 11475:2018
ISO 11475:2017(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2017, Published in Switzerland
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form
or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior
written permission. Permission can be requested from either ISO at the address below or ISO’s member body in the country of
the requester.
ISO copyright office
Ch. de Blandonnet 8 • CP 401
CH-1214 Vernier, Geneva, Switzerland
Tel. +41 22 749 01 11
Fax +41 22 749 09 47
copyright@iso.org
www.iso.org
ii © ISO 2017 – All rights reserved

---------------------- Page: 4 ----------------------

SIST ISO 11475:2018
ISO 11475:2017(E)

Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 3
5 Apparatus and equipment . 3
6 Calibration . 4
7 Sampling . 5
8 Preparation of test pieces . 5
9 Procedure. 5
10 Calculation and expression of results . 6
11 Precision . 7
12 Test report . 7
Annex A (normative) Spectral characteristics of reflectometers for determining
tristimulus values . 8
Annex B (normative) UV calibration service .13
Annex C (informative) Precision .15
Bibliography .16
© ISO 2017 – All rights reserved iii

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SIST ISO 11475:2018
ISO 11475:2017(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.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).
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. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/ patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO’s adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see the following
URL: w w w . i s o .org/ iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 6, Paper, board and pulps.
This third edition cancels and replaces the second edition (ISO 11475:2004), which has been technically
revised. The major change is to allow for calculations to use ASTM E308 for instruments that have
bandpass correction and still maintain the non-bandpass-correction procedure. This third edition also
includes Precision Data.
iv © ISO 2017 – All rights reserved

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SIST ISO 11475:2018
INTERNATIONAL STANDARD ISO 11475:2017(E)
Paper and board — Determination of CIE whiteness,
D65/10° (outdoor daylight)
1 Scope
This document specifies the procedure to be used for determining the whiteness of papers and boards.
The values obtained correspond to the visual appearance of white papers and boards with or without
fluorescent whitening agents when they are viewed under the CIE D65 daylight standard illuminant.
It is based on reflectance data obtained over the full visible spectral range (VIS) in contrast to the
measurement of ISO brightness which is limited to the blue region of VIS.
In addition, it specifies a method for adjustment of the UV content to correspond to the CIE D65
[10][11]
daylight illuminant , insofar as results obtained when fluorescent whitening agents are present
are dependent upon the UV content of the radiation falling upon the sample. It is specific for white
fluorescent paper samples where the emission due to the fluorescent whitening agent (FWA) occurs in
the blue region of the visible spectrum.
This method is not applicable to coloured papers containing fluorescent dyes.
This document should be read in conjunction with ISO 2469.
[9]
NOTE 1 This document is based on the CIE whiteness formula, published in CIE 15.3-2004 .
NOTE 2 A related International Standard, ISO 11476, specifying the procedure for obtaining values
corresponding to the appearance of these products under indoor illumination, has also been published.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements 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 2469:2014, Paper, board and pulps — Measurement of diffuse radiance factor (diffuse reflectance factor)
ISO 4094, Paper, board and pulps — International calibration of testing apparatus — Nomination and
acceptance of standardizing and authorized laboratories
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at http:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
NOTE The symbols used here are selected to maintain consistency, wherever possible, with Reference [8].
© ISO 2017 – All rights reserved 1

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SIST ISO 11475:2018
ISO 11475:2017(E)

3.1
reflectance factor
R
ratio of the radiation reflected by a body to that reflected by the perfect reflecting diffuser under the
same conditions
Note 1 to entry: The ratio is expressed as a percentage.
3.2
intrinsic reflectance factor
R
∞
reflectance factor (3.1) of a layer or pad of the 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
3.3
diffuse radiance factor
β
ratio of the diffusely reflected radiance of a body in a given direction to that of the perfect reflecting
diffuser under specified conditions of irradiation
Note 1 to entry: For fluorescent (luminescent) materials, the specified conditions of irradiation in this document
are for CIE Standard Illuminant D65 and the diffuse radiance factor is strictly the total radiance factor, β, which
contains two components, the reflected radiance factor, β , and the luminescent radiance factor, β , so that
R L
     β = β + β
R L
Note 2 to entry: For non-fluorescent materials, the diffuse radiance factor, β, is simply the reflectance factor, R (3.1).
3.4
intrinsic diffuse radiance factor
β
∞
diffuse radiance factor (3.3) of a layer or pad of the 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 diffuse radiance factor
Note 1 to entry: For fluorescent (luminescent) materials, the intrinsic diffuse radiance factor is, strictly speaking,
the total intrinsic radiance factor, β , which contains two components: the intrinsic reflected radiance factor,
∞
β , and the intrinsic luminescent radiance factor, β , so that
∞,R ∞,L
     β = β + β
∞ ∞,R ∞,L
Note 2 to entry: For non-fluorescent materials, the intrinsic diffuse radiance factor, β , is simply the intrinsic
R
reflectance factor, R (3.2).
∞
3.5
CIE whiteness value
W
10
measure of whiteness derived from the CIE tristimulus values
Note 1 to entry: CIE whiteness is dimensionless and is expressed as whiteness units.
3.6
green tint value
red tint value
T
W10
measure of the deviation from whiteness of the test material towards the green or red region
Note 1 to entry: The tint value is dimensionless and is expressed as tint units.
Note 2 to entry: A positive value of T indicates a greenish tint and a negative value indicates a reddish tint.
W10
2 © ISO 2017 – All rights reserved

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SIST ISO 11475:2018
ISO 11475:2017(E)

3.7
fluorescence component
F
10
measure of the extent to which the whiteness of the material is affected by excitation of the added
fluorescent whitening agent (FWA)
Note 1 to entry: The suffix 10 in the terms given in 3.5 to 3.7 is used to indicate that the value refers to the
CIE 1964 (10°) observer.
4 Principle
The diffuse radiance factor of the material is determined under standardized conditions after the
instrument has been adjusted so that a reference standard has the same CIE whiteness value as it
would have under CIE standard illuminant D65, and the CIE whiteness value and the tint value are
calculated. The fluorescence component of the whiteness is calculated from the difference between this
whiteness value and the whiteness value obtained when the fluorescence emission from the material is
eliminated, for instance, by the introduction of a sharp cut-off UV-absorbing filter into the light beams.
5 Apparatus and equipment
5.1 Reflectometer or spectrophotometer, having the geometric, spectral and photometric
characteristics described in ISO 2469:2014, Annex A, calibrated in accordance with the provisions
of ISO 2469:2014, Annex B, and equipped with a light source having an adequate UV content and a
means of adjusting the relative UV content so that the measured CIE whiteness value agrees with that
corresponding to the CIE standard illuminant D65.
For the measurement of reflectance factors with the fluorescence effect eliminated, the instrument
shall be equipped with a sharp cut-off, UV-absorbing filter having a transmittance not exceeding 5,0 %
at and below a wavelength of 410 nm and not exceeding 50 % at a wavelength of 420 nm. The cut-
off filter shall have characteristics such that a reliable reflectance value is obtained at 420 nm. The
reflectance value obtained at 420 nm shall then be considered for computational purposes to be the
value which applies at all lower wavelengths at which it is not possible to make any measurement.
For the measurement of fluorescent papers, photometric linearity up to a scale reading of at least 200 %
is necessary in the wavelength region corresponding to the fluorescent emission.
5.1.1 In the case of a filter reflectometer, pairs of filters giving the photoelectric detectors of the
reflectometer responses equivalent to the CIE tristimulus values X , Y , Z of the test piece, evaluated
10 10 10
[4]
for the CIE standard illuminant D65 and CIE 1964 (10°) observer .
5.1.2 In the case of an abridged spectrophotometer, a means of calculating the weighted means
according to the requirements of the CIE standard illuminant D65 and CIE 1964 (10°) observer using
the weighting functions given in Annex A and Reference [7], where Table A.1 and Table A.2 are used for
instruments without bandpass correction and Table A.3 and Table A.4 are used for instruments with
bandpass correction.
5.2 Working standards.
5.2.1 Two plates of flat opal glass or ceramic material, cleaned as described in ISO 2469.
5.2.2 A stable plastic or other tablet incorporating a fluorescent whitening agent.
© ISO 2017 – All rights reserved 3

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SIST ISO 11475:2018
ISO 11475:2017(E)

5.3 Reference standards for calibration of the instrument and working standards.
5.3.1 Non-fluorescent reference standard for calibration, fulfilling the requirements for
international reference standards of level 3 (IR3) as prescribed in ISO 2469.
5.3.2 Fluorescent reference standard for use in adjusting the UV content of the radiation incident
upon the sample, having whiteness values and other relevant data as specified in Annex B and fulfilling
the requirements for international reference standards of level 3 (IR3) as prescribed in ISO 2469.
Use new reference standards sufficiently frequently to ensure satisfactory calibration and
UV adjustment.
5.4 Black cavity, having a reflectance factor which does not differ from its nominal value by more than
0,2 % at all wavelengths. The black cavity shall be stored upside down in a dust-free environment or with
a protective cover.
The condition of the black cavity should be checked by reference to the instrument maker.
6 Calibration
6.1 Using the values assigned to the non-fluorescent reference standard (5.3.1), calibrate the instrument
with the UV cut-off filters removed from the radiation beams. The setting of the UV adjustment filter is
not important at this stage.
6.2 Using the appropriate measurement procedure, measure the diffuse radiance factors of the
fluorescent reference standard (5.3.2), calculate the whiteness value (see 10.1) and compare the value
obtained with that assigned to the fluorescent reference standard.
A measured whiteness value higher than the assigned value indicates that the relative UV content is too
high and vice versa.
6.3 Using the UV adjustment filter or other adjustment device, adjust the UV content of the illumination
until measurement gives the correct whiteness value.
NOTE If the UV content is too low, it may be necessary to replace the UV adjustment filter with a filter which
raises rather than lowers the relative UV content.
6.4 Repeat the calibration as described in 6.1 using the non-fluorescent reference standard (5.3.1) with
the UV adjustment filter in the position which gave the correct whiteness value. Repeat the measurement
of the whiteness of the fluorescent reference standard (5.3.2) as described in 6.2. If the whiteness value
obtained does not agree with the assigned value, adjust the position of the UV adjustment filter until
measurement gives the correct whiteness value as described in 6.3.
6.5 Repeat 6.4 until the correct value for the whiteness of the fluorescent reference standard is
obtained with the instrument correctly calibrated to the non-fluorescent reference standard. The relative
UV content is now correctly adjusted with respect to whiteness so that the setting gives the CIE whiteness
value equivalent to the CIE standard illuminant D65 and CIE 1964 (10°) observer. Record the setting of
the UV adjustment.
NOTE 1 Variations in the green/red tint value can still arise and it cannot be assumed that the tristimulus
values and other parameters will also be exactly applicable to the D65 illuminant.
NOTE 2 In some instruments, the procedure indicated in 6.2 to 6.5 is performed automatically.
4 © ISO 2017 – All rights reserved

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SIST ISO 11475:2018
ISO 11475:2017(E)

6.6 Calibrate the fluorescent working standard (5.2.2) as the working standard.
This working standard shall only be used in the specific instrument in which it is calibrated and shall
only be used to monitor changes in the lamps. It shall be recalibrated against a fluorescent reference
standard of level 3 (5.3.2) if the lamps are changed.
6.7 Calibrate the opal glass or ceramic plates (5.2.1) as working standards as described in ISO 2469.
6.8 After adjustment of the UV content as in 6.1 to 6.5, insert the UV cut-off filter and calibrate the
instrument in this position with the UV adjustment unchanged.
7 Sampling
Sampling is not included in this document. If the mean quality of a lot is to be determined, sampling
shall be according to ISO 186. Otherwise, the method of sampling should be reported and care should
be taken to ensure that the test pieces are representative of the sample available.
8 Preparation of test pieces
Avoiding watermarks, dirt and obvious defects, cut rectangular test pieces approximatel
...

SLOVENSKI STANDARD
oSIST ISO 11475:2018
01-september-2018
3DSLUNDUWRQLQOHSHQND'RORþDQMHEHOLQHSR&,('ƒ]XQDQMDGQHYQD
VYHWORED
Paper and board -- Determination of CIE whiteness, D65/10 degrees (outdoor daylight)
Papier et carton -- Détermination du degré de blanc CIE, D65/10 degrés (lumière du jour
extérieure)
Ta slovenski standard je istoveten z: ISO 11475:2017
ICS:
85.060 Papir, karton in lepenka Paper and board
oSIST ISO 11475:2018 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------

oSIST ISO 11475:2018

---------------------- Page: 2 ----------------------

oSIST ISO 11475:2018
INTERNATIONAL ISO
STANDARD 11475
Third edition
2017-05
Paper and board — Determination
of CIE whiteness, D65/10° (outdoor
daylight)
Papier et carton — Détermination du degré de blanc CIE, D65/10°
(lumière du jour extérieure)
Reference number
ISO 11475:2017(E)
©
ISO 2017

---------------------- Page: 3 ----------------------

oSIST ISO 11475:2018
ISO 11475:2017(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2017, Published in Switzerland
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form
or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior
written permission. Permission can be requested from either ISO at the address below or ISO’s member body in the country of
the requester.
ISO copyright office
Ch. de Blandonnet 8 • CP 401
CH-1214 Vernier, Geneva, Switzerland
Tel. +41 22 749 01 11
Fax +41 22 749 09 47
copyright@iso.org
www.iso.org
ii © ISO 2017 – All rights reserved

---------------------- Page: 4 ----------------------

oSIST ISO 11475:2018
ISO 11475:2017(E)

Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 3
5 Apparatus and equipment . 3
6 Calibration . 4
7 Sampling . 5
8 Preparation of test pieces . 5
9 Procedure. 5
10 Calculation and expression of results . 6
11 Precision . 7
12 Test report . 7
Annex A (normative) Spectral characteristics of reflectometers for determining
tristimulus values . 8
Annex B (normative) UV calibration service .13
Annex C (informative) Precision .15
Bibliography .16
© ISO 2017 – All rights reserved iii

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oSIST ISO 11475:2018
ISO 11475:2017(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.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).
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. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/ patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO’s adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see the following
URL: w w w. i s o .org/ iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 6, Paper, board and pulps.
This third edition cancels and replaces the second edition (ISO 11475:2004), which has been technically
revised. The major change is to allow for calculations to use ASTM E308 for instruments that have
bandpass correction and still maintain the non-bandpass-correction procedure. This third edition also
includes Precision Data.
iv © ISO 2017 – All rights reserved

---------------------- Page: 6 ----------------------

oSIST ISO 11475:2018
INTERNATIONAL STANDARD ISO 11475:2017(E)
Paper and board — Determination of CIE whiteness,
D65/10° (outdoor daylight)
1 Scope
This document specifies the procedure to be used for determining the whiteness of papers and boards.
The values obtained correspond to the visual appearance of white papers and boards with or without
fluorescent whitening agents when they are viewed under the CIE D65 daylight standard illuminant.
It is based on reflectance data obtained over the full visible spectral range (VIS) in contrast to the
measurement of ISO brightness which is limited to the blue region of VIS.
In addition, it specifies a method for adjustment of the UV content to correspond to the CIE D65
[10][11]
daylight illuminant , insofar as results obtained when fluorescent whitening agents are present
are dependent upon the UV content of the radiation falling upon the sample. It is specific for white
fluorescent paper samples where the emission due to the fluorescent whitening agent (FWA) occurs in
the blue region of the visible spectrum.
This method is not applicable to coloured papers containing fluorescent dyes.
This document should be read in conjunction with ISO 2469.
[9]
NOTE 1 This document is based on the CIE whiteness formula, published in CIE 15.3-2004 .
NOTE 2 A related International Standard, ISO 11476, specifying the procedure for obtaining values
corresponding to the appearance of these products under indoor illumination, has also been published.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements 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 2469:2014, Paper, board and pulps — Measurement of diffuse radiance factor (diffuse reflectance factor)
ISO 4094, Paper, board and pulps — International calibration of testing apparatus — Nomination and
acceptance of standardizing and authorized laboratories
3 Terms a nd definiti ons
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at http:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
NOTE The symbols used here are selected to maintain consistency, wherever possible, with Reference [8].
© ISO 2017 – All rights reserved 1

---------------------- Page: 7 ----------------------

oSIST ISO 11475:2018
ISO 11475:2017(E)

3.1
r e f le c t a nc e f ac t or
R
ratio of the radiation reflected by a body to that reflected by the perfect reflecting diffuser under the
same conditions
Note 1 to entry: The ratio is expressed as a percentage.
3.2
i nt r i n s ic r e f le c t a nc e f ac t or
R
∞
reflectance factor (3.1) of a layer or pad of the 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
3.3
diffuse radiance factor
β
ratio of the diffusely reflected radiance of a body in a given direction to that of the perfect reflecting
diffuser under specified conditions of irradiation
Note 1 to entry: For fluorescent (luminescent) materials, the specified conditions of irradiation in this document
are for CIE Standard Illuminant D65 and the diffuse radiance factor is strictly the total radiance factor, β, which
contains two components, the reflected radiance factor, β , and the luminescent radiance factor, β , so that
R L
     β = β + β
R L
Note 2 to entry: For non-fluorescent materials, the diffuse radiance factor, β, is simply the reflectance factor, R (3.1).
3.4
intrinsic diffuse radiance factor
β
∞
diffuse radiance factor (3.3) of a layer or pad of the 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 diffuse radiance factor
Note 1 to entry: For fluorescent (luminescent) materials, the intrinsic diffuse radiance factor is, strictly speaking,
the total intrinsic radiance factor, β , which contains two components: the intrinsic reflected radiance factor,
∞
β , and the intrinsic luminescent radiance factor, β , so that
∞,R ∞,L
     β = β + β
∞ ∞,R ∞,L
Note 2 to entry: For non-fluorescent materials, the intrinsic diffuse radiance factor, β , is simply the intrinsic
R
reflectance factor, R (3.2).
∞
3.5
CIE whiteness value
W
10
measure of whiteness derived from the CIE tristimulus values
Note 1 to entry: CIE whiteness is dimensionless and is expressed as whiteness units.
3.6
green tint value
red tint value
T
W10
measure of the deviation from whiteness of the test material towards the green or red region
Note 1 to entry: The tint value is dimensionless and is expressed as tint units.
Note 2 to entry: A positive value of T indicates a greenish tint and a negative value indicates a reddish tint.
W10
2 © ISO 2017 – All rights reserved

---------------------- Page: 8 ----------------------

oSIST ISO 11475:2018
ISO 11475:2017(E)

3.7
f luor e s c enc e c omponent
F
10
measure of the extent to which the whiteness of the material is affected by excitation of the added
fluorescent whitening agent (FWA)
Note 1 to entry: The suffix 10 in the terms given in 3.5 to 3.7 is used to indicate that the value refers to the
CIE 1964 (10°) observer.
4 Principle
The diffuse radiance factor of the material is determined under standardized conditions after the
instrument has been adjusted so that a reference standard has the same CIE whiteness value as it
would have under CIE standard illuminant D65, and the CIE whiteness value and the tint value are
calculated. The fluorescence component of the whiteness is calculated from the difference between this
whiteness value and the whiteness value obtained when the fluorescence emission from the material is
eliminated, for instance, by the introduction of a sharp cut-off UV-absorbing filter into the light beams.
5 Apparatus and equipment
5.1 Reflectometer or spectrophotometer, having the geometric, spectral and photometric
characteristics described in ISO 2469:2014, Annex A, calibrated in accordance with the provisions
of ISO 2469:2014, Annex B, and equipped with a light source having an adequate UV content and a
means of adjusting the relative UV content so that the measured CIE whiteness value agrees with that
corresponding to the CIE standard illuminant D65.
For the measurement of reflectance factors with the fluorescence effect eliminated, the instrument
shall be equipped with a sharp cut-off, UV-absorbing filter having a transmittance not exceeding 5,0 %
at and below a wavelength of 410 nm and not exceeding 50 % at a wavelength of 420 nm. The cut-
off filter shall have characteristics such that a reliable reflectance value is obtained at 420 nm. The
reflectance value obtained at 420 nm shall then be considered for computational purposes to be the
value which applies at all lower wavelengths at which it is not possible to make any measurement.
For the measurement of fluorescent papers, photometric linearity up to a scale reading of at least 200 %
is necessary in the wavelength region corresponding to the fluorescent emission.
5.1.1 In the case of a filter reflectometer, pairs of filters giving the photoelectric detectors of the
reflectometer responses equivalent to the CIE tristimulus values X , Y , Z of the test piece, evaluated
10 10 10
[4]
for the CIE standard illuminant D65 and CIE 1964 (10°) observer .
5.1.2 In the case of an abridged spectrophotometer, a means of calculating the weighted means
according to the requirements of the CIE standard illuminant D65 and CIE 1964 (10°) observer using
the weighting functions given in Annex A and Reference [7], where Table A.1 and Table A.2 are used for
instruments without bandpass correction and Table A.3 and Table A.4 are used for instruments with
bandpass correction.
5.2 Working standards.
5.2.1 Two plates of flat o pal glass or ceramic material, cleaned as described in ISO 2469.
5.2.2 A stable plastic or other tablet incorporating a fluorescent whitening agent.
© ISO 2017 – All rights reserved 3

---------------------- Page: 9 ----------------------

oSIST ISO 11475:2018
ISO 11475:2017(E)

5.3 Reference standards for calibration of the instrument and working standards.
5.3.1 Non-fluorescent reference standard for calib ration, fulfilling the requirements for
international reference standards of level 3 (IR3) as prescribed in ISO 2469.
5.3.2 Fluorescent reference standard for use in adjusting the UV content of the radiation incident
upon the sample, having whiteness values and other relevant data as specified in Annex B and fulfilling
the requirements for international reference standards of level 3 (IR3) as prescribed in ISO 2469.
Use new reference standards sufficiently frequently to ensure satisfactory calibration and
UV adjustment.
5.4 Black cavity, having a reflectance factor which does not differ from its nominal value by more than
0,2 % at all wavelengths. The black cavity shall be stored upside down in a dust-free environment or with
a protective cover.
The condition of the black cavity should be checked by reference to the instrument maker.
6 Calibration
6.1 Using the values assigned to the non-fluorescent reference standard (5.3.1), calibrate the instrument
with the UV cut-off filters removed from the radiation beams. The setting of the UV adjustment filter is
not important at this stage.
6.2 Using the appropriate measurement procedure, measure the diffuse radiance factors of the
fluorescent reference standard (5.3.2), calculate the whiteness value (see 10.1) and compare the value
obtained with that assigned to the fluorescent reference standard.
A measured whiteness value higher than the assigned value indicates that the relative UV content is too
high and vice versa.
6.3 Using the UV adjustment filter or other adjustment device, adjust the UV content of the illumination
until measurement gives the correct whiteness value.
NOTE If the UV content is too low, it may be necessary to replace the UV adjustment filter with a filter which
raises rather than lowers the relative UV content.
6.4 Repeat the calibration as described in 6.1 using the non-fluorescent reference standard (5.3.1) with
the UV adjustment filter in the position which gave the correct whiteness value. Repeat the measurement
of the whiteness of the fluorescent reference standard (5.3.2) as described in 6.2. If the whiteness value
obtained does not agree with the assigned value, adjust the position of the UV adjustment filter until
measurement gives the correct whiteness value as described in 6.3.
6.5 Repeat 6.4 until the correct value for the whiteness of the fluorescent reference standard is
obtained with the instrument correctly calibrated to the non-fluorescent reference standard. The relative
UV content is now correctly adjusted with respect to whiteness so that the setting gives the CIE whiteness
value equivalent to the CIE standard illuminant D65 and CIE 1964 (10°) observer. Record the setting of
the UV adjustment.
NOTE 1 Variations in the green/red tint value can still arise and it cannot be assumed that the tristimulus
values and other parameters will also be exactly applicable to the D65 illuminant.
NOTE 2 In some instruments, the procedure indicated in 6.2 to 6.5 is performed automatically.
4 © ISO 2017 – All rights reserved

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oSIST ISO 11475:2018
ISO 11475:2017(E)

6.6 Calibrate the fluorescent working standard (5.2.2) as the working standard.
This working standard shall only be used in the specific instrument in which it is calibrated and shall
only be used to monitor changes in the lamps. It shall be recalibrated against a fluorescent reference
standard of level 3 (5.3.2) if the lamps are changed.
6.7 Calibrate the opal glass or ceramic plates (5.2.1) as working standards as described in ISO 2469.
6.8 After adjustment of the UV content as in 6.1 to 6.5, insert the UV cut-off filter and calibrate the
instrument in this position with the UV adjustment unchanged.
7 Sampling
Sampling is not included in this document. If the mean quality of a lot is to be determined, sampling
shall be according to ISO 186. Otherwise, the method of sampling should be reported and care should
be taken to ensure that the test pieces are representative of the sample available.
8 Preparation of test pieces
Avoiding watermarks, dirt and obvious defects, cut rectangular test pieces approxima
...