SIST EN ISO 3668:2020
(Main)Paints and varnishes - Visual comparison of colour of paints (ISO 3668:2017)
Paints and varnishes - Visual comparison of colour of paints (ISO 3668:2017)
ISO 3668:2017 specifies a method for the visual comparison of the colour of films of paints or related products against a standard (either a reference standard or a freshly prepared standard) using artificial light sources in a standard booth.
It is not applicable to coatings containing special-effect pigments, e.g. metallic, without previous agreement on all details of illuminating and viewing conditions
Beschichtungsstoffe - Visueller Vergleich der Farbe von Beschichtungen (ISO 3668:2017)
Dieses Dokument legt ein Verfahren zum visuellen Abmustern der Farbe von Beschichtungen gegen einen Standard (entweder einen Bezugsstandard oder einen frisch hergestellten Standard) unter künstlichen Lichtquellen in einer Farbabmusterungskabine fest.
Es ist nicht anwendbar auf Beschichtungen, die spezielle Effektpigmente, z. B. Metalleffektpigmente, enthalten, wenn nicht alle Einzelheiten der Beleuchtungs und Beobachtungsbedingungen vorher vereinbart wurden.
Peintures et vernis - Comparaison visuelle de la couleur des peintures (ISO 3668:2017)
Le présent document spécifie une méthode de comparaison visuelle de la couleur de feuils de peinture ou de produits assimilés par rapport à un étalon (soit un étalon de référence, soit un étalon fraîchement préparé) utilisant des sources de lumière artificielle dans une cabine normalisée.
Il ne s'applique pas aux revêtements contenant des pigments à effets spéciaux, par exemple métalliques, sans accord préalable sur tous les détails concernant les conditions d'éclairage et d'observation.
Barve in laki - Vizualna primerjava barve premazov (ISO 3668:2017)
General Information
Relations
Buy Standard
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN ISO 3668:2020
01-april-2020
Nadomešča:
SIST EN ISO 3668:2002
Barve in laki - Vizualna primerjava barve premazov (ISO 3668:2017)
Paints and varnishes - Visual comparison of colour of paints (ISO 3668:2017)
Beschichtungsstoffe - Visueller Vergleich der Farbe von Beschichtungen (ISO
3668:2017)
Peintures et vernis - Comparaison visuelle de la couleur des peintures (ISO 3668:2017)
Ta slovenski standard je istoveten z: EN ISO 3668:2020
ICS:
87.040 Barve in laki Paints and varnishes
SIST EN ISO 3668:2020 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
---------------------- Page: 1 ----------------------
SIST EN ISO 3668:2020
---------------------- Page: 2 ----------------------
SIST EN ISO 3668:2020
EN ISO 3668
EUROPEAN STANDARD
NORME EUROPÉENNE
February 2020
EUROPÄISCHE NORM
ICS 87.040 Supersedes EN ISO 3668:2001
English Version
Paints and varnishes - Visual comparison of colour of
paints (ISO 3668:2017)
Peintures et vernis - Comparaison visuelle de la Beschichtungsstoffe - Visueller Vergleich der Farbe von
couleur des peintures (ISO 3668:2017) Beschichtungen (ISO 3668:2017)
This European Standard was approved by CEN on 4 November 2019.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2020 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 3668:2020 E
worldwide for CEN national Members.
---------------------- Page: 3 ----------------------
SIST EN ISO 3668:2020
EN ISO 3668:2020 (E)
Contents Page
European foreword . 3
2
---------------------- Page: 4 ----------------------
SIST EN ISO 3668:2020
EN ISO 3668:2020 (E)
European foreword
The text of ISO 3668:2017 has been prepared by Technical Committee ISO/TC 35 "Paints and
varnishes” of the International Organization for Standardization (ISO) and has been taken over as
EN ISO 3668:2020 by Technical Committee CEN/TC 139 “Paints and varnishes” the secretariat of which
is held by DIN.
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 August 2020, and conflicting national standards shall
be withdrawn at the latest by August 2020.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN ISO 3668:2001.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the
United Kingdom.
Endorsement notice
The text of ISO 3668:2017 has been approved by CEN as EN ISO 3668:2020 without any modification.
3
---------------------- Page: 5 ----------------------
SIST EN ISO 3668:2020
---------------------- Page: 6 ----------------------
SIST EN ISO 3668:2020
INTERNATIONAL ISO
STANDARD 3668
Third edition
2017-05
Paints and varnishes — Visual
comparison of colour of paints
Peintures et vernis — Comparaison visuelle de la couleur des
peintures
Reference number
ISO 3668:2017(E)
©
ISO 2017
---------------------- Page: 7 ----------------------
SIST EN ISO 3668:2020
ISO 3668:2017(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: 8 ----------------------
SIST EN ISO 3668:2020
ISO 3668:2017(E)
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 1
5 Illumination for colour matching . 2
5.1 General . 2
5.2 Artificial illumination by means of a colour matching booth . 2
6 Observer . 2
7 Test panels and reference standards . 3
7.1 General . 3
7.2 Reference standards . 3
7.3 Preparation and coating . . 3
7.4 Drying . 4
8 Procedure for colour comparison . 4
8.1 General . 4
8.2 Colour comparison . 4
9 Assessment of metamerism . 4
10 Test report . 5
Annex A (normative) Colour difference rating scheme . 6
Annex B (informative) Metameric matches . 7
Bibliography . 8
© ISO 2017 – All rights reserved iii
---------------------- Page: 9 ----------------------
SIST EN ISO 3668:2020
ISO 3668:2017(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 35, Paints and varnishes, Subcommittee
SC 9, General test methods for paints and varnishes.
This third edition cancels and replaces the second edition (ISO 3668:1998), which has been technically
revised with the following changes:
— testing using natural daylight has been deleted;
— CIE illuminant FL 11 has been added as third type of artificial light source;
— determination of the film thickness has been deleted because it is irrelevant for the assessment of
colour (the paint layer needs to be sufficient in hiding; the hiding power is more important);
— the normative references have been updated;
— the supplementary test conditions previously in Annex A have been integrated in the test report.
iv © ISO 2017 – All rights reserved
---------------------- Page: 10 ----------------------
SIST EN ISO 3668:2020
INTERNATIONAL STANDARD ISO 3668:2017(E)
Paints and varnishes — Visual comparison of colour of
paints
1 Scope
This document specifies a method for the visual comparison of the colour of films of paints or related
products against a standard (either a reference standard or a freshly prepared standard) using artificial
light sources in a standard booth.
It is not applicable to coatings containing special-effect pigments, e.g. metallic, without previous
agreement on all details of illuminating and viewing conditions
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 1514, Paints and varnishes — Standard panels for testing
ISO 3270, Paints and varnishes and their raw materials — Temperatures and humidities for conditioning
and testing
ISO 11664-2, Colorimetry — Part 2: CIE standard illuminants
ISO 18314-1, Analytical colorimetry — Part 1: Practical colour measurement
ISO 23603, Standard method of assessing the spectral quality of daylight simulators for visual appraisal
and measurement of colour
CIE 15.3, Colorimetry
CIE 51.2, A method for assessing the quality of daylight simulators for colorimetry
3 Terms and definitions
No terms and definitions are listed in this document.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— IEC Electropedia: available at http:// www .electropedia .org/
— ISO Online browsing platform: available at http:// www .iso .org/ obp
4 Principle
The colours of the paint films to be compared are observed under specified illumination and viewing
conditions, using a colour matching booth. For the expression of colour difference components (hue,
chroma and lightness) a procedure is described, i.e. description by using a particular rating scheme.
Assessment of metamerism is also taken into account.
© ISO 2017 – All rights reserved 1
---------------------- Page: 11 -----------------
...
SLOVENSKI STANDARD
SIST EN ISO 3668:2020
01-april-2020
Nadomešča:
SIST EN ISO 3668:2002
Barve in laki - Vizualna primerjava barve premazov (ISO 3668:2017)
Paints and varnishes - Visual comparison of colour of paints (ISO 3668:2017)
Beschichtungsstoffe - Visueller Vergleich der Farbe von Beschichtungen (ISO
3668:2017)
Peintures et vernis - Comparaison visuelle de la couleur des peintures (ISO 3668:2017)
Ta slovenski standard je istoveten z: EN ISO 3668:2020
ICS:
87.040 Barve in laki Paints and varnishes
SIST EN ISO 3668:2020 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
---------------------- Page: 1 ----------------------
SIST EN ISO 3668:2020
---------------------- Page: 2 ----------------------
SIST EN ISO 3668:2020
EN ISO 3668
EUROPEAN STANDARD
NORME EUROPÉENNE
February 2020
EUROPÄISCHE NORM
ICS 87.040
English Version
Paints and varnishes - Visual comparison of colour of
paints (ISO 3668:2017)
Peintures et vernis - Comparaison visuelle de la Beschichtungsstoffe - Visueller Vergleich der Farbe von
couleur des peintures (ISO 3668:2017) Beschichtungen (ISO 3668:2017)
This European Standard was approved by CEN on 4 November 2019.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2020 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 3668:2020 E
worldwide for CEN national Members.
---------------------- Page: 3 ----------------------
SIST EN ISO 3668:2020
EN ISO 3668:2020 (E)
Contents Page
European foreword . 3
2
---------------------- Page: 4 ----------------------
SIST EN ISO 3668:2020
EN ISO 3668:2020 (E)
European foreword
The text of ISO 3668:2017 has been prepared by Technical Committee ISO/TC 35 "Paints and
varnishes” of the International Organization for Standardization (ISO) and has been taken over as
EN ISO 3668:2020 by Technical Committee CEN/TC 139 “Paints and varnishes” the secretariat of which
is held by DIN.
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 August 2020, and conflicting national standards shall
be withdrawn at the latest by August 2020.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the
United Kingdom.
Endorsement notice
The text of ISO 3668:2017 has been approved by CEN as EN ISO 3668:2020 without any modification.
3
---------------------- Page: 5 ----------------------
SIST EN ISO 3668:2020
---------------------- Page: 6 ----------------------
SIST EN ISO 3668:2020
INTERNATIONAL ISO
STANDARD 3668
Third edition
2017-05
Paints and varnishes — Visual
comparison of colour of paints
Peintures et vernis — Comparaison visuelle de la couleur des
peintures
Reference number
ISO 3668:2017(E)
©
ISO 2017
---------------------- Page: 7 ----------------------
SIST EN ISO 3668:2020
ISO 3668:2017(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: 8 ----------------------
SIST EN ISO 3668:2020
ISO 3668:2017(E)
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 1
5 Illumination for colour matching . 2
5.1 General . 2
5.2 Artificial illumination by means of a colour matching booth . 2
6 Observer . 2
7 Test panels and reference standards . 3
7.1 General . 3
7.2 Reference standards . 3
7.3 Preparation and coating . . 3
7.4 Drying . 4
8 Procedure for colour comparison . 4
8.1 General . 4
8.2 Colour comparison . 4
9 Assessment of metamerism . 4
10 Test report . 5
Annex A (normative) Colour difference rating scheme . 6
Annex B (informative) Metameric matches . 7
Bibliography . 8
© ISO 2017 – All rights reserved iii
---------------------- Page: 9 ----------------------
SIST EN ISO 3668:2020
ISO 3668:2017(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 35, Paints and varnishes, Subcommittee
SC 9, General test methods for paints and varnishes.
This third edition cancels and replaces the second edition (ISO 3668:1998), which has been technically
revised with the following changes:
— testing using natural daylight has been deleted;
— CIE illuminant FL 11 has been added as third type of artificial light source;
— determination of the film thickness has been deleted because it is irrelevant for the assessment of
colour (the paint layer needs to be sufficient in hiding; the hiding power is more important);
— the normative references have been updated;
— the supplementary test conditions previously in Annex A have been integrated in the test report.
iv © ISO 2017 – All rights reserved
---------------------- Page: 10 ----------------------
SIST EN ISO 3668:2020
INTERNATIONAL STANDARD ISO 3668:2017(E)
Paints and varnishes — Visual comparison of colour of
paints
1 Scope
This document specifies a method for the visual comparison of the colour of films of paints or related
products against a standard (either a reference standard or a freshly prepared standard) using artificial
light sources in a standard booth.
It is not applicable to coatings containing special-effect pigments, e.g. metallic, without previous
agreement on all details of illuminating and viewing conditions
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 1514, Paints and varnishes — Standard panels for testing
ISO 3270, Paints and varnishes and their raw materials — Temperatures and humidities for conditioning
and testing
ISO 11664-2, Colorimetry — Part 2: CIE standard illuminants
ISO 18314-1, Analytical colorimetry — Part 1: Practical colour measurement
ISO 23603, Standard method of assessing the spectral quality of daylight simulators for visual appraisal
and measurement of colour
CIE 15.3, Colorimetry
CIE 51.2, A method for assessing the quality of daylight simulators for colorimetry
3 Terms and definitions
No terms and definitions are listed in this document.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— IEC Electropedia: available at http:// www .electropedia .org/
— ISO Online browsing platform: available at http:// www .iso .org/ obp
4 Principle
The colours of the paint films to be compared are observed under specified illumination and viewing
conditions, using a colour matching booth. For the expression of colour difference components (hue,
chroma and lightness) a procedure is described, i.e. description by using a particular rating scheme.
Assessment of metamerism is also taken into account.
© ISO 2017 – All rights reserved 1
---------------------- Page: 11 ----------------------
SIST EN ISO 3668:2020
ISO 366
...
SLOVENSKI STANDARD
oSIST prEN ISO 3668:2019
01-julij-2019
Barve in laki - Vizualna primerjava barve premazov (ISO 3668:2017)
Paints and varnishes - Visual comparison of colour of paints (ISO 3668:2017)
Beschichtungsstoffe - Visueller Vergleich der Farbe von Beschichtungen (ISO
3668:2017)
Peintures et vernis - Comparaison visuelle de la couleur des peintures (ISO 3668:2017)
Ta slovenski standard je istoveten z: prEN ISO 3668
ICS:
87.040 Barve in laki Paints and varnishes
oSIST prEN ISO 3668:2019 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
---------------------- Page: 1 ----------------------
oSIST prEN ISO 3668:2019
---------------------- Page: 2 ----------------------
oSIST prEN ISO 3668:2019
INTERNATIONAL ISO
STANDARD 3668
Third edition
2017-05
Paints and varnishes — Visual
comparison of colour of paints
Peintures et vernis — Comparaison visuelle de la couleur des
peintures
Reference number
ISO 3668:2017(E)
©
ISO 2017
---------------------- Page: 3 ----------------------
oSIST prEN ISO 3668:2019
ISO 3668:2017(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 prEN ISO 3668:2019
ISO 3668:2017(E)
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 1
5 Illumination for colour matching . 2
5.1 General . 2
5.2 Artificial illumination by means of a colour matching booth . 2
6 Observer . 2
7 Test panels and reference standards . 3
7.1 General . 3
7.2 Reference standards . 3
7.3 Preparation and coating . . 3
7.4 Drying . 4
8 Procedure for colour comparison . 4
8.1 General . 4
8.2 Colour comparison . 4
9 Assessment of metamerism . 4
10 Test report . 5
Annex A (normative) Colour difference rating scheme . 6
Annex B (informative) Metameric matches . 7
Bibliography . 8
© ISO 2017 – All rights reserved iii
---------------------- Page: 5 ----------------------
oSIST prEN ISO 3668:2019
ISO 3668:2017(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 35, Paints and varnishes, Subcommittee
SC 9, General test methods for paints and varnishes.
This third edition cancels and replaces the second edition (ISO 3668:1998), which has been technically
revised with the following changes:
— testing using natural daylight has been deleted;
— CIE illuminant FL 11 has been added as third type of artificial light source;
— determination of the film thickness has been deleted because it is irrelevant for the assessment of
colour (the paint layer needs to be sufficient in hiding; the hiding power is more important);
— the normative references have been updated;
— the supplementary test conditions previously in Annex A have been integrated in the test report.
iv © ISO 2017 – All rights reserved
---------------------- Page: 6 ----------------------
oSIST prEN ISO 3668:2019
INTERNATIONAL STANDARD ISO 3668:2017(E)
Paints and varnishes — Visual comparison of colour of
paints
1 Scope
This document specifies a method for the visual comparison of the colour of films of paints or related
products against a standard (either a reference standard or a freshly prepared standard) using artificial
light sources in a standard booth.
It is not applicable to coatings containing special-effect pigments, e.g. metallic, without previous
agreement on all details of illuminating and viewing conditions
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 1514, Paints and varnishes — Standard panels for testing
ISO 3270, Paints and varnishes and their raw materials — Temperatures and humidities for conditioning
and testing
ISO 11664-2, Colorimetry — Part 2: CIE standard illuminants
ISO 18314-1, Analytical colorimetry — Part 1: Practical colour measurement
ISO 23603, Standard method of assessing the spectral quality of daylight simulators for visual appraisal
and measurement of colour
CIE 15.3, Colorimetry
CIE 51.2, A method for assessing the quality of daylight simulators for colorimetry
3 Terms and definitions
No terms and definitions are listed in this document.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
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— ISO Online browsing platform: available at http:// www .iso .org/ obp
4 Principle
The colours of the paint films to be compared are observed under specified illumination and viewing
conditions, using a colour matching booth. For the expression of colour difference components (hue,
chroma and lightness) a procedure is described, i.e. description by using a particular rating scheme.
Assessment of metamerism is also taken into account.
© ISO 2017 – All rights reserved 1
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oSIST prEN ISO 3668:2019
ISO 3668:2017(E)
5 Illumination for colour matching
5.1 General
The quality of natural daylight is variable and observers’ judgements are likely to be affected by nearby
coloured objects. For referee purposes, therefore, closely controlled artificial illumination in a colour-
matching booth shall be used. The observer shall wear clothing of a neutral colour and no strongly
coloured surfaces, other than panels under test, shall be permitted in the field of view.
5.2 Artificial illumination by means of a colour matching booth
The colour matching booth shall be an enclosure from which external light is excluded and which is
illuminated by a light source giving a spectral power distribution falling on the test panel, approximating
to that of CIE standard Illuminant D65, CIE standard Illuminant A (as specified in ISO 11664-2) or CIE
illuminant FL 11 (as specified in CIE 15.3).
Where a light source having a different spectral distribution is used, it shall be agreed by the interested
parties.
The quality of simulation of daylight shall be assessed by the CIE method specified in CIE Publication
No. 51.2 and ISO 23603. The spectral distribution of the illuminant shall be in category BC (CIELAB)
or better.
The level of illumination at the colour-matching position shall be between 1 000 lx and 4 000 lx, a figure
towards the upper end of the range being desirable for dark colours.
The interior of the colour-matching booth for general use shall be painted a matt neutral grey (the
amount of a* and b* should be less than 1,0) with a lightness L* of about 45 to 55. However, when mainly
light colours and near white colours are to be compared, the interior of the booth may be painted so as
to have a lightness L* of about 65 or higher in order to give a lower brightness contrast with the colour
to be examined; when mainly dark colours are to be compared, the interior of the booth may be painted
matt blac
...
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