SIST ISO 13655:2018

Graphic technology - Spectral measurement and colorimetric computation for graphic arts images

ISO 13655:2017 specifies procedures for the measurements and colorimetric computations appropriate to objects that reflect, transmit and emit light, such as flat-panel displays. It also specifies procedures for computation of colorimetric parameters for graphic arts images. Graphic arts include, but are not limited to, the preparation of material for, and volume production by, production printing processes that include offset lithography, letterpress, flexography, gravure, screen and digital printing.
ISO 13655:2017 does not address spectral measurements appropriate to other specific application needs, such as those used during the production of materials, for example, printing paper and proofing media.

Technologie graphique - Mesurage spectral et calcul colorimétrique relatifs aux images dans les arts graphiques

Grafična tehnologija - Spektrometrija in kolorimetrični izračuni za grafične upodobitve

Ta dokument določa postopke za meritve in kolorimetrične izračune, ustrezne za objekte, ki odsevajo, prenašajo in oddajajo svetlobo (npr. ploskovni zasloni). Določa tudi postopke za izračun kolorimetričnih parametrov za grafične upodobitve. Grafične dejavnosti med drugim vključujejo pripravo materiala in količinsko produkcijo s postopki produkcijskega tiskanja, ki vključujejo ofsetno litografijo, žigosanje, fleksografijo, graviranje ter zaslonsko in digitalno tiskanje.
Ta dokument ne obravnava spektralnih meritev, primernih za druge specifične načine uporabe, ki se na primer uporabljajo pri proizvodnji materialov, kot so tiskarski papir in preskusni mediji.

General Information

• Status: Published
• Publication Date: 08-Jan-2018
• ICS: 17.180.20 - Colours and measurement of light
• ICS: 37.100.01 - Graphic technology in general
• Technical Committee: GRT - Graphical technology
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 12-Oct-2017
• Due Date: 17-Dec-2017
• Completion Date: 09-Jan-2018
• Ref Project: ISO 13655:2017 - Graphic technology — Spectral measurement and colorimetric computation for graphic arts images

Relations

• Replaces: SIST ISO 13655:2010 - Graphic technology - Spectral measurement and colorimetric computation for graphic arts images
• Effective Date: 01-Feb-2018

Standards Content (Sample)

SLOVENSKI STANDARD
01-februar-2018
1DGRPHãþD
SIST ISO 13655:2010
*UDILþQDWHKQRORJLMD6SHNWURPHWULMDLQNRORULPHWULþQLL]UDþXQL]DJUDILþQH
XSRGRELWYH
Graphic technology - Spectral measurement and colorimetric computation for graphic
arts images
Technologie graphique - Mesurage spectral et calcul colorimétrique relatifs aux images
dans les arts graphiques
Ta slovenski standard je istoveten z: ISO 13655:2017
ICS:
17.180.20 Barve in merjenje svetlobe Colours and measurement of
light
37.100.01 *UDILþQDWHKQRORJLMDQD Graphic technology in
VSORãQR general
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

INTERNATIONAL ISO
STANDARD 13655
Third edition
2017-07
Graphic technology — Spectral
measurement and colorimetric
computation for graphic arts images
Technologie graphique — Mesurage spectral et calcul colorimétrique
relatifs aux images dans les arts graphiques
Reference number
©
ISO 2017
© 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. [phone]
Fax [phone]
[e-mail]
www.iso.org
ii © ISO 2017 – All rights reserved

Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Spectral measurement requirements . 4
4.1 Instrument standardization and adjustment . 4
4.2 Reflectance factor measurement . 4
4.2.1 Wavelength range, wavelength interval and bandwidth . 4
4.2.2 Illumination requirements and measurement conditions . 5
4.2.3 Sample backing material . 7
4.2.4 Measurement geometry . 7
4.2.5 Data reporting . 7
4.3 Transmittance factor measurement . 8
4.3.1 Wavelength range, wavelength interval and bandwidth . 8
4.3.2 Measurement geometry . 8
4.3.3 Illumination requirements and measurement conditions . 8
4.3.4 Resolution and data reporting . 8
4.4 Self-luminous displays (spectral radiance) measurement . 9
4.4.1 Wavelength range, wavelength interval and bandwidth . 9
4.4.2 Measurement geometry . 9
4.4.3 Polarization . 9
4.4.4 Resolution and data reporting .10
5 Colorimetric computation requirements .10
5.1 Calculation of tristimulus values for reflecting and transmitting samples .10
5.1.1 General.10
5.1.2 Calculations with data having 5 nm interval and bandwidth .11
5.1.3 Calculations with data having 10 nm interval and bandwidth .11
5.1.4 Calculations with data having other intervals and bandwidth .11
5.2 Calculation of tristimulus values for self-luminous displays .11
5.3 CIE 1976 (L*a*b*) colour space; CIELAB colour space .13
5.3.1 General.13
5.3.2 CIELAB colour space formulae .13
5.3.3 CIE 1976 colour difference formulae .14
5.3.4 CIEDE2000 colour difference formulae .14
6 Measurement data reporting requirements .15
6.1 Required information .15
6.2 Recommended information .15
6.3 Electronic data reporting .15
Annex A (normative) Sample backing .16
Annex B (informative) Geometry .21
Annex C (informative) Improving inter-instrument agreement .24
Annex D (informative) Certified reference materials (CRMs) .26
Annex E (informative) Procedures for widening the bandwidth .28
Annex F (informative) Fluorescent specimens .30
Annex G (normative) Test method for UV-cut conformance .32
Annex H (informative) Special cases: Use of polarization .34
Annex I (informative) Example computations for converting spectral measurements to
tristimulus values .35
Annex J (normative) Computation of the CIELAB total colour difference (∆E*ab) .41
Annex K (normative) Computation of the CIEDE2000 total colour difference (ΔE ) .42
Annex L (informative) Impact of measurement band pass on spectral quantities .46
Bibliography .48
iv © ISO 2017 – 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.
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 130, Graphic technology, in collaboration
with Technical Committee ISO/TC 42, Photography.
This third edition cancels and replaces the second edition (ISO 13655:2009), which has been technically
revised to:
— clarify the requirements of measurement mode M1;
— restrict the use of unnecessarily wide bandpass and sampling intervals;
— provide more realistic specification for the optical properties of a white backing material;
— restrict the adjustment method of predicting the fluorescent reflectance factor to UV activated
substrates.
Introduction
There are many choices allowed when making spectral measurements and performing colorimetric
computations. The specific choices made can result in different numerical values for the same property
for the same sample. Thus, it might not be possible to make valid comparisons unless the data being
compared are all based on the same set of measurement and computational choices. The purpose of
this document is to specify a limited number of such choices for the measurement and computation
of the colorimetric characteristics of graphic arts images and specimens, such as test charts, to allow
valid and comparable data to be obtained. While this document references ISO 3664, the International
Standard established for viewing conditions in graphic arts and photography, it is not expected that
measured colorimetric data will provide an absolute correlation with visual colour appearance.
When the prior revision of this document was started, it was observed that almost all graphic arts
specimens exhibited fluorescence. In most cases, this was due to optical brightening agents (OBA)
contained in the paper substrates. In rare cases, the printing inks were fluorescent. According to the
recommendations of the 1996 version of this document, this would have meant that t
...

INTERNATIONAL ISO
STANDARD 13655
Third edition
2017-07
Graphic technology — Spectral
measurement and colorimetric
computation for graphic arts images
Technologie graphique — Mesurage spectral et calcul colorimétrique
relatifs aux images dans les arts graphiques
Reference number
©
ISO 2017
© 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. [phone]
Fax [phone]
[e-mail]
www.iso.org
ii © ISO 2017 – All rights reserved

Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Spectral measurement requirements . 4
4.1 Instrument standardization and adjustment . 4
4.2 Reflectance factor measurement . 4
4.2.1 Wavelength range, wavelength interval and bandwidth . 4
4.2.2 Illumination requirements and measurement conditions . 5
4.2.3 Sample backing material . 7
4.2.4 Measurement geometry . 7
4.2.5 Data reporting . 7
4.3 Transmittance factor measurement . 8
4.3.1 Wavelength range, wavelength interval and bandwidth . 8
4.3.2 Measurement geometry . 8
4.3.3 Illumination requirements and measurement conditions . 8
4.3.4 Resolution and data reporting . 8
4.4 Self-luminous displays (spectral radiance) measurement . 9
4.4.1 Wavelength range, wavelength interval and bandwidth . 9
4.4.2 Measurement geometry . 9
4.4.3 Polarization . 9
4.4.4 Resolution and data reporting .10
5 Colorimetric computation requirements .10
5.1 Calculation of tristimulus values for reflecting and transmitting samples .10
5.1.1 General.10
5.1.2 Calculations with data having 5 nm interval and bandwidth .11
5.1.3 Calculations with data having 10 nm interval and bandwidth .11
5.1.4 Calculations with data having other intervals and bandwidth .11
5.2 Calculation of tristimulus values for self-luminous displays .11
5.3 CIE 1976 (L*a*b*) colour space; CIELAB colour space .13
5.3.1 General.13
5.3.2 CIELAB colour space formulae .13
5.3.3 CIE 1976 colour difference formulae .14
5.3.4 CIEDE2000 colour difference formulae .14
6 Measurement data reporting requirements .15
6.1 Required information .15
6.2 Recommended information .15
6.3 Electronic data reporting .15
Annex A (normative) Sample backing .16
Annex B (informative) Geometry .21
Annex C (informative) Improving inter-instrument agreement .24
Annex D (informative) Certified reference materials (CRMs) .26
Annex E (informative) Procedures for widening the bandwidth .28
Annex F (informative) Fluorescent specimens .30
Annex G (normative) Test method for UV-cut conformance .32
Annex H (informative) Special cases: Use of polarization .34
Annex I (informative) Example computations for converting spectral measurements to
tristimulus values .35
Annex J (normative) Computation of the CIELAB total colour difference (∆E*ab) .41
Annex K (normative) Computation of the CIEDE2000 total colour difference (ΔE ) .42
Annex L (informative) Impact of measurement band pass on spectral quantities .46
Bibliography .48
iv © ISO 2017 – 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.
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 130, Graphic technology, in collaboration
with Technical Committee ISO/TC 42, Photography.
This third edition cancels and replaces the second edition (ISO 13655:2009), which has been technically
revised to:
— clarify the requirements of measurement mode M1;
— restrict the use of unnecessarily wide bandpass and sampling intervals;
— provide more realistic specification for the optical properties of a white backing material;
— restrict the adjustment method of predicting the fluorescent reflectance factor to UV activated
substrates.
Introduction
There are many choices allowed when making spectral measurements and performing colorimetric
computations. The specific choices made can result in different numerical values for the same property
for the same sample. Thus, it might not be possible to make valid comparisons unless the data being
compared are all based on the same set of measurement and computational choices. The purpose of
this document is to specify a limited number of such choices for the measurement and computation
of the colorimetric characteristics of graphic arts images and specimens, such as test charts, to allow
valid and comparable data to be obtained. While this document references ISO 3664, the International
Standard established for viewing conditions in graphic arts and photography, it is not expected that
measured colorimetric data will provide an absolute correlation with visual colour appearance.
When the prior revision of this document was started, it was observed that almost all graphic arts
specimens exhibited fluorescence. In most cases, this was due to optical brightening agents (OBA)
contained in the paper substrates. In rare cases, the printing inks were fluorescent. According to the
recommendations of the 1996 version of this document, this would have meant that the source used for
the measurements (i.e. the spectral power distribution of the specimen illumination) was required to
closely match CIE illuminant D50. Yet when the 2009 revision was started, not a single colour-measuring
instrument sold for the graphic arts market provided an illumination system that closely matched CIE
illuminant D50. Instead, most instruments used incandescent lamps for light sources. The spectral
power distributions of such lamps have varying amounts of UV content. The variation in UV content
between instruments could easily amount to a colour difference of 5 Δb* when measuring substrates
with a high level of optical brightening agents. Consequently, the measurement results for unprinted
paper substrates and lighter colours differed appreciably between different instrument models. For a
thorough study of fluorescence effects, see CIE Publication 163.
It had also been observed that graphic arts viewing booths vary with respect to UV content, ev
...