ISO 8254-2:2003

INTERNATIONAL ISO
STANDARD 8254-2
First edition
2003-01-15

Paper and board — Measurement of
specular gloss —
Part 2:
75° gloss with a parallel beam, DIN
method
Papiers et cartons — Mesurage du brillant spéculaire —
Partie 2: Brillant à 75° avec un faisceau parallèle, méthode DIN




Reference number
ISO 8254-2:2003(E)
©
ISO 2003

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ISO 8254-2:2003(E)
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ISO 8254-2:2003(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 3.
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 part of ISO 8254 may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 8254-2 was prepared by the European Committee for Standardization (CEN) in collaboration with
Technical Committee ISO/TC 6, Paper, board and pulps, in accordance with the Agreement on technical
cooperation between ISO and CEN (Vienna Agreement).
Throughout the text of this document, read ".this European Standard." to mean ".this International
Standard.".
ISO 8254 consists of the following parts, under the general title Paper and board — Measurement of specular
gloss:
— Part 1: 75° gloss with a converging beam, TAPPI method
— Part 2: 75° gloss with a parallel beam, DIN method
— Part 3: 20° gloss
Annex A forms a normative part of this part of ISO 8254. Annex B is for information only.
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ISO 8254-2:2003(E)


Contents
Foreword.v
Introduction .1
1 Scope .1
2 Normative references .1
3 Terms and definitions.2
4 Principle.2
5 Equipment.2
5.1 Reflectometer .2
5.2 Gloss standards.2
5.2.1 Zero-gloss standards .3
5.2.2 Primary gloss standards.3
5.2.3 Working standards .3
5.2.4 Intermediate gloss standards.3
6 Sampling.4
7 Preparation of test pieces.4
7.1 Conditioning.4
7.2 Preparation .4
8 Procedure .5
8.1 Calibration .5
8.2 Determination of reflectometer value .5
8.3 Calculation and expression of results.5
9 Test report .6
Annex A (normative) Description of the instrument.7
A.1 Design of the reflectometer value .7
A.2 Properties of the reflectometer.9
A.2.1 Dimensions and tolerances of angles .10
A.2.2 Spectral adaptation.10
A.2.3 Linearity and drift to display.11
A.2.4 Polarization.11
A.3 Test piece-holding device.11
Annex B (informative) Nominated organizations for calibration of intermediate gloss standards .12
Annex C (informative) Bibliography .13
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ISO 8254-2:2003(E)


Foreword
This document (EN ISO 8254-2:2003) has been prepared by Technical Committee CEN /TC 172, "Pulp, paper and
board", the secretariat of which is held by DIN, in collaboration with Technical Committee ISO/TC 6 "Paper, board
and pulps".
This European Standard shall be given the status of a national standard, either by publication of an identical text or
by endorsement, at the latest by July 2003, and conflicting national standards shall be withdrawn at the latest by
July 2003.
This Standard contains the following parts:
 Part 1: 75° gloss with a converging beam, TAPPI method
 Part 2: 75° gloss with a parallel beam, DIN method
 Part 3: 20° gloss
In addition, CEN has developed the European Standard EN 14086 "Paper and board - Measurement of specular
gloss - 45° gloss with a parallel beam, DIN-method.
The European Standard EN 14086 and the International Standard ISO/DIS 8254-3 are intended for use with high
gloss papers.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to implement this European Standard: Austria, Belgium, Czech Republic, Denmark, Finland,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal,
Slovakia, Spain, Sweden, Switzerland and the United Kingdom.
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ISO 8254-2:2003(E)
Introduction
Visual gloss is a sensory impression which cannot yet be described completely. Some important physical variables
which influence gloss are however known. The sensory perception of gloss under a suitable illumination results
from a physical stimulus due to reflection of light from a surface. This reflection is defined by an indicatrix which
changes with the angle of incidence. The maximum indicatrix value which is decisive for visual gloss impression is
associated with specular reflection, at an angle of reflection which is approximately equal to the angle of incidence.
The reflectometer value is determined by averaging the reflection in a defined angular region centered in the
specular direction.
NOTE 1 A reflectometer value is a measure of the visual gloss only when the optical conditions of measurement,
such as angles and apertures of illumination and observation are similar to the conditions of viewing.
NOTE 2 Because luminance and structure enter to some extent into the reflectometer value of the test piece, only
the comparison of test pieces with nearly the same luminance and structure is meaningful. The influence of
luminance on the measurement result decreases rapidly with increasing reflectometer value and increasing angle
of reflection.
The proportion of specular reflection in the entire reflection increases with increasing angle of incidence. Very matt
surfaces generate a noticeable degree of specular reflection and, therefore, a noticeable gloss effect only above a
certain minimum angle of incidence. On the other hand, a large angle of incidence reduces the ability to differentiate
between surfaces of high gloss.
NOTE 3 Manufacturers of coated papers usually divide their products into two classes, according to their surface
gloss: matt coating and gloss coating. However, these classes are only defined approximately. The matt class has
reflectometer values, measured according to this European Standard, from 0 to approximately 20. The glossy class
has reflectometer values higher than this value. As there is no precise correlation between reflectometer values
measured with different geometries, it is advisable to compare the reflectometer values only within a single class of
papers and using the same measuring geometry.
This European Standard describes measurement at an angle of incidence of 75° using a parallel beam geometry
commonly known as the 75° DIN method. A second European Standard describes measurement at an angle of 45°
(see EN 14086).
1 Scope
This European Standard specifies a photometric test method for the assessment of visual gloss by means of a
reflectometer value measured at an angle of 75°. It is applicable to plane paper and board surfaces of gloss levels
below 65, measured according to this European Standard. It should be the preferred method for paper and board
surfaces of gloss levels below 20, measured according to this European Standard. Materials containing optical
brightening agents may be measured.
2 Normative references
This European Standard incorporates by dated or undated reference, provisions from other publications. These
normative references are cited at the appropriate places in the text, and the publications are listed hereafter. For
dated references, subsequent amendments to or revisions of any of these publications apply to this European
Standard only when incorporated in it by amendment or revision. For undated references the latest edition of the
publication referred to applies (including amendments).
CIE-Publication No. 38, Radiometric and photometric characteristics.
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ISO 8254-2:2003(E)
EN ISO 186, Paper and board — Sampling to determine average quality (ISO 186:1994).
EN 20187, Paper, board and pulps — Standard atmosphere for conditioning and testing and procedure for
monitoring the atmosphere and conditioning of samples (ISO 187:1990).
ISO 10110-5, Optic and optical instruments — Preparation of drawings for optical elements and systems — Part 5:
Surface form tolerances.
3 Terms and definitions
For the purposes of this part of ISO 8254, the following terms and definitions apply.
3.1
indicatrix
angular distribution of the reflected light which is measured as illuminance on the receptor.
3.2
reflectometer
instrument for measuring quantities pertaining to reflection of light.
3.3
reflectometer value
measured variable which, for a given angle of incidence, is proportional to the integral of the reflection indicatrix
within the solid angle defined by the apertures (see Annex A.2.1) and is equal to 100 times the ratio of the value
obtained for the sample to that of a defined specularly reflecting surface (5.2.2).
3.4
specular gloss
reflectometer value as defined in 3.3.
NOTE 1 The defined specularly reflecting surface thus has an assigned reflectometer value of 100. Reflectometer
values are therefore not percentages.
NOTE 2 These definitions are based on definitions in CIE-Publication No. 17.4.
4 Principle
The sample is illuminated with a collimated beam at an angle of 75 ° to the normal, and the reflectometer value is
measured within a solid angle defined by a given aperture at an angle of reflection equal to the angle of incidence.
The scale of the reflectometer is calibrated with reference to the reflection from a black glass plate or a quartz
wedge with a specific refractive index.
5 Equipment
5.1 Reflectometer
The reflectometer shall consist of the following principal components: a collimator, a decollimator, an electric supply
for the light source device, a photoelectronic receptor and a sample holder, as described in annex A.
5.2 Gloss standards
The reflectometer is calibrated by means of a zero-gloss standard and a high gloss standard with a reflectometer
value between about 80 and 100. This high gloss standard can be either a primary gloss standard or a working
gloss standard.
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ISO 8254-2:2003(E)
Intermediate gloss standards with assigned reflectometer values are used to check the adjustment of the device.
NOTE As reflectometer values of gloss standards may change due to environmental influences, they should be
checked at least once per year.
5.2.1 Zero-gloss standards
A zero-gloss standard is a gloss standard which, in the ideal case, absorbs all light falling on it. A black cavity lined
with black velvet or felt is one realisation of such a gloss standard that has been proven in practice.
5.2.2 Primary gloss standards
A primary gloss standard is a gloss standard whose reflectometer value can be calculated by means of its
refractive index using the Fresnel equation. The reflectometer value is defined as being equal to 100 for a black
glass pla
...