ISO 8254-3:2016

Paper and board — Measurement of specular gloss — Part 3: 20 degree gloss with a converging beam, TAPPI method

ISO 8254-3:2016 specifies a method for measuring the specular gloss of paper and board at an angle of 20° to the normal to the paper surface. It is applicable chiefly to highly glossy surfaces, such as cast-coated, lacquered, highly varnished or waxed papers and high-gloss ink films. NOTE This part of ISO 8254 has been developed from TAPPI T653[2], ISO 2813[1] and from ISO 8254‑1.

Papier et carton — Mesurage du brillant spéculaire — Partie 3: Brillant à 20 degrés avec un faisceau convergent, méthode TAPPI

General Information

• Status: Published
• Publication Date: 05-Apr-2016
• ICS: 85.060 - Paper and board
• Technical Committee: ISO/TC 6 - Paper, board and pulps
• Drafting Committee: ISO/TC 6/WG 3 - Optical properties
• Current Stage: 9093 - International Standard confirmed
• Completion Date: 10-Sep-2021

Relations

• Revises: ISO 8254-3:2004 - Paper and board — Measurement of specular gloss — Part 3: 20 degree gloss with a converging beam, TAPPI method
• Effective Date: 17-May-2014

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 8254-3
Second edition
2016-04-01
Paper and board — Measurement of
specular gloss —
Part 3:
20° gloss with a converging beam,
TAPPI method
Papier et carton — Mesurage du brillant spéculaire —
Partie 3: Brillant à 20° avec un faisceau convergent, méthode
TAPPI
Reference number
ISO 8254-3:2016(E)
©
ISO 2016

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ISO 8254-3:2016(E)

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© ISO 2016, Published in Switzerland
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form
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ii © ISO 2016 – All rights reserved

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ISO 8254-3:2016(E)

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 2
5 Apparatus . 2
5.1 Gloss meter . 2
5.2 Gloss standards . 2
6 Sampling . 4
7 Preparation of test pieces . 4
8 Calibration of the instrument . 4
9 Procedure. 4
10 Calculation and expression of results . 5
11 Test report . 5
Annex A (normative) Specification of the optical system of the gloss meter .6
Annex B (informative) Precision . 9
Bibliography .10
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ISO 8254-3:2016(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
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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 meaning of ISO specific terms and expressions related to conformity
assessment, as well as information about ISO’s adherence to the WTO principles in the Technical
Barriers to Trade (TBT) see the following URL: Foreword - Supplementary information
The committee responsible for this document is ISO/TC 6, Paper, board and pulps.
This second edition cancels and replaces the first edition (ISO 8254-3:2004), which has been editorially
revised to provide a precision statement, to update the bibliographic references and to provide
additional clarification on Scope and application of the method described in 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 with a converging beam, TAPPI method
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ISO 8254-3:2016(E)

Introduction
This part of ISO 8254 deals with the assessment of the specular gloss of paper and board at an angle
of 20°, using a converging beam geometry commonly known as the TAPPI method and described in
[2]
TAPPI T653 . ISO 8254-1 and ISO 8254-2 deal with the measurement of specular gloss at 75°.
Although the word “measurement” is used, it is to be noted that this is strictly speaking only an
“assessment” because the definition of gloss (see 3.1) relates to a scale of visual perception, whereas
the method described uses a physical measurement of mixed regular and diffuse reflection. The exact
correlation between the visual perception and the scale established by the physical measurement is not
known. However, this physical gloss scale has proved to be useful for a number of technical applications
and, consequently, its standardization is justified.
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INTERNATIONAL STANDARD ISO 8254-3:2016(E)
Paper and board — Measurement of specular gloss —
Part 3:
20° gloss with a converging beam, TAPPI method
1 Scope
This part of ISO 8254 specifies a method for measuring the specular gloss of paper and board at an
angle of 20° to the normal to the paper surface. It is applicable chiefly to highly glossy surfaces, such as
cast-coated, lacquered, highly varnished or waxed papers and high-gloss ink films.
[2] [1]
NOTE This part of ISO 8254 has been developed from TAPPI T653 , ISO 2813 and from ISO 8254-1.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. 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 187, Paper, board and pulps — Standard atmosphere for conditioning and testing and procedure for
monitoring the atmosphere and conditioning of samples
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
gloss (of a surface)
mode of appearance by which reflected highlights of objects are perceived as superimposed on the
surface due to the directionally selective properties of that surface
[3]
[SOURCE: CIE S 017/E:2011, 17-500 ]
3.2
regular reflection
specular reflection
reflection in accordance with the laws of geometrical optics, without diffusion
[3]
[SOURCE: CIE S 017/E:2001, 17-1077 ]
3.3
diffuse reflection
diffusion by reflection in which, on the macroscopic scale, there is no regular reflection
[3]
[SOURCE: CIE S 017/E:2011, 17-305 ]
3.4
specular gloss
measured variable equal to 100 times the ratio of the luminous flux reflected by the test-piece surface
into a specified aperture at the specified angle of specular reflection to that reflected by a gloss
standard specularly reflecting surface under the same conditions
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ISO 8254-3:2016(E)

4 Principle
Light incident on the test-piece surface at an angle of 20° to the normal and reflected from the surface at
an angle of 20° to the normal into a defined aperture is detected by a photodetector, the output of which
is displayed on a meter. The gloss scale is established by reference to the reflection from a standard
black glass of known refractive index. Annex B provides precision data.
5 Apparatus
5.1 Gloss meter
It has the general arrangement and relative dimensions of the principal parts described in Annex A. It
consists of:
a) a source of light;
b) a lens giving a converging beam of light incident on the test piece;
c) a suitable device, such as a suction plate to hold the test piece flat, if required;
d) a photodetector to receive and measure certain of the rays reflected by the test piece.
These components are combined in a light-tight housing that is matte black inside and is structurally
and optically stable at the operating temperature.
5.2 Gloss standards
5.2.1 Primary gloss standard, a flat, clean and polished surface, having a refractive index of 1,540 at
587,6 nm (the helium D-line). This may be shown by the Fresnel formulae to measure 100 gloss units on
a scale related to the theoretical primary gloss standard. The theoretical primary specular gloss standard
[4]
is an ideal, completely reflecting plane mirror having an assigned gloss value of 2 199.
5.2.2 High gloss reference standard, a clean plaque of polished black glass for which the 20° specular
reflectance has been computed from its refractive index measured at a wavelength of 587,6 nm.
If the refractive index differs from 1,540, the gloss value shall be calculated as follows:
GK=×100 (1)
where
2 2
   
05, 05,
22 2 2 2
   
nn cos sεε−− in n − sincεε− os
() ()
   
   
+
 05,   05, 
22 2 2 2
   
nn cos sεε+− in n − sincεε+ os
() ()
   
   
Kn,ε = (2)
()
2 2
   
05, 05,
22 2 2
2
   
1,,540 cos εε−−1 540 sin 1,540 − sincεε− os
() ()
   
   
+
 05,   05, 
22 2 2 2
   
1,,540 cos ε +−1 540 ssinε 1,540 −− sincεε+ os
() ()
   
   
where
n is the refractive index of the glass;
ε is the angle of incidence.
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ISO 8254-3:2016(E)

When ε = 20°, the formula reduces to
2 2
 
05, 05,
   
 
22 2
0,,93970nn−− 117 n 0,,117 −0 9397
   − 
( ) ( )
 
   
Kn,,20° =10 994 + (3)
()  
0,55 05,
   
 22 2 
0,,93970nn+− 117 n −0,,117 +0 9397
   
) )
( (
 
   
 
NOTE 1 If the refractive index is known, the gloss value can be calculated by adding or subtracting from 100,0
a value of 0,29 for each 0,001 departure of the refractive index from the standard value of 1,540. For example, for
a glass of refractive index n = 1,523, the assigned gloss value G would be
02,,91 540−n
()
G = 100−
0,001
= 290n −346,60 (4)
= 95,1
This method is, however, valid only for refractive index values between 1,50 and 1,54. It is not applicable
to quartz standards for which n is about 1,46.
NOTE 2 Commercial gloss meters with 20° gloss scales based on International Standards with refractive index
of 1,567 for general materials (paint, plastics, ceramics) will report different gloss readings for paper samples
which
...