SIST EN ISO 7668:2021
(Main)Anodizing of aluminium and its alloys - Measurement of specular reflectance and specular gloss of anodic oxidation coatings at angles of 20°, 45°, 60° or 85° (ISO 7668:2021)
Anodizing of aluminium and its alloys - Measurement of specular reflectance and specular gloss of anodic oxidation coatings at angles of 20°, 45°, 60° or 85° (ISO 7668:2021)
This document specifies methods for the measurement of specular reflectance and specular gloss of
flat samples of anodized aluminium using geometries of 20° (Method A), 45° (Method B), 60° (Method
C) and 85° (Method D) and of specular reflectance by an additional 45° method (Method E) employing a
narrow acceptance angle.
The methods described are intended mainly for use with clear anodized surfaces. They can be used
with colour-anodized aluminium, but only with similar colours.
Anodisieren von Aluminium und Aluminiumlegierungen - Messung des gerichteten Reflexionsgrades und des Spiegelglanzes von anodisch erzeugten Oxidschichten bei Winkeln von 20°, 45°, 60° oder 85° (ISO 7668:2021)
Dieses Dokument legt Verfahren zur Messung des gerichteten Reflexionsgrades und des Spiegelglanzes von ebenen Proben aus anodisch oxidiertem Aluminium unter Anwendung der geometrischen Messbedingungen bei 20° (Verfahren A), 45° (Verfahren B), 60° (Verfahren C) und 85° (Verfahren D) sowie ein weiteres Verfahren zur Messung des gerichteten Reflexionsgrades bei 45° (Verfahren E) fest, bei dem ein kleiner Empfängerwinkel verwendet wird.
Die beschriebenen Verfahren sind hauptsächlich für farblos anodisierte Oberflächen vorgesehen. Sie können für farbig anodisiertes Aluminium verwendet werden, aber nur bei gleichen Farben.
Anodisation de l'aluminium et de ses alliages - Mesurage des caractéristiques de réflectivité et de brillant spéculaires des couches anodiques à angle fixe de 20°, 45°, 60° ou 85° (ISO 7668:2021)
Le présent document spécifie des méthodes de mesure de la réflectivité spéculaire et du brillant spéculaire d'échantillons plats d'aluminium anodisé sous des angles de 20° (Méthode A), 45° (Méthode B), 60° (Méthode C) et 85° (Méthode D), plus une autre méthode à 45° (Méthode E) à petit angle d'ouverture pour le mesurage de la réflectivité spéculaire.
Les méthodes décrites sont principalement utilisables sur des surfaces plates anodisées claires. Elles peuvent être utilisées sur de l'aluminium anodisé coloré, mais dans ce cas, uniquement pour des couleurs semblables.
Anodizacija aluminija in aluminijevih zlitin - Merjenje odbojnosti in sijaja anodizirane plasti pod koti 20°, 45°, 60° ali 85° (ISO 7668:2021)
General Information
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Buy Standard
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN ISO 7668:2021
01-november-2021
Nadomešča:
SIST EN ISO 7668:2018
Anodizacija aluminija in aluminijevih zlitin - Merjenje odbojnosti in sijaja
anodizirane plasti pod koti 20°, 45°, 60° ali 85° (ISO 7668:2021)
Anodizing of aluminium and its alloys - Measurement of specular reflectance and
specular gloss of anodic oxidation coatings at angles of 20°, 45°, 60° or 85° (ISO
7668:2021)Anodisieren von Aluminium und Aluminiumlegierungen - Messung des gerichteten
Reflexionsgrades und des Spiegelglanzes von anodisch erzeugten Oxidschichten bei
Winkeln von 20°, 45°, 60° oder 85° (ISO 7668:2021)
Anodisation de l'aluminium et de ses alliages - Mesurage des caractéristiques de
réflectivité et de brillant spéculaires des couches anodiques à angle fixe de 20°, 45°, 60°
ou 85° (ISO 7668:2021)Ta slovenski standard je istoveten z: EN ISO 7668:2021
ICS:
25.220.20 Površinska obdelava Surface treatment
77.120.10 Aluminij in aluminijeve zlitine Aluminium and aluminium
alloys
SIST EN ISO 7668:2021 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
---------------------- Page: 1 ----------------------SIST EN ISO 7668:2021
---------------------- Page: 2 ----------------------
SIST EN ISO 7668:2021
EN ISO 7668
EUROPEAN STANDARD
NORME EUROPÉENNE
September 2021
EUROPÄISCHE NORM
ICS 25.220.20 Supersedes EN ISO 7668:2018
English Version
Anodizing of aluminium and its alloys - Measurement of
specular reflectance and specular gloss of anodic oxidation
coatings at angles of 20°, 45°, 60° or 85° (ISO 7668:2021)
Anodisation de l'aluminium et de ses alliages - Anodisieren von Aluminium und
Mesurage des caractéristiques de réflectivité et de Aluminiumlegierungen - Messung des gerichteten
brillant spéculaires des couches anodiques à angle fixe Reflexionsgrades und des Spiegelglanzes von anodisch
de 20°, 45°, 60° ou 85° (ISO 7668:2021) erzeugten Oxidschichten bei Winkeln von 20°, 45°, 60°
oder 85° (ISO 7668:2021)This European Standard was approved by CEN on 17 August 2021.
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
© 2021 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 7668:2021 E
worldwide for CEN national Members.---------------------- Page: 3 ----------------------
SIST EN ISO 7668:2021
EN ISO 7668:2021 (E)
Contents Page
European foreword ....................................................................................................................................................... 3
---------------------- Page: 4 ----------------------SIST EN ISO 7668:2021
EN ISO 7668:2021 (E)
European foreword
This document (EN ISO 7668:2021) has been prepared by Technical Committee ISO/TC 79 "Light
metals and their alloys" in collaboration with Technical Committee CEN/TC 132 “Aluminium and
aluminium alloys” the secretariat of which is held by AFNOR.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 March 2022, and conflicting national standards shall
be withdrawn at the latest by March 2022.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 7668:2018.Any feedback and questions on this document should be directed to the users’ national standards
body/national committee. A complete listing of these bodies can be found on the CEN websites.
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 7668:2021 has been approved by CEN as EN ISO 7668:2021 without any modification.
---------------------- Page: 5 ----------------------SIST EN ISO 7668:2021
---------------------- Page: 6 ----------------------
SIST EN ISO 7668:2021
INTERNATIONAL ISO
STANDARD 7668
Fourth edition
2021-08
Anodizing of aluminium and its
alloys — Measurement of specular
reflectance and specular gloss of
anodic oxidation coatings at angles of
20°, 45°, 60° or 85°
Anodisation de l'aluminium et de ses alliages — Mesurage des
caractéristiques de réflectivité et de brillant spéculaires des couches
anodiques à angle fixe de 20°, 45°, 60° ou 85°
Reference number
ISO 7668:2021(E)
ISO 2021
---------------------- Page: 7 ----------------------
SIST EN ISO 7668:2021
ISO 7668:2021(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2021
All rights reserved. Unless otherwise specified, or required in the context of its implementation, 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
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2021 – All rights reserved
---------------------- Page: 8 ----------------------
SIST EN ISO 7668:2021
ISO 7668:2021(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
6 Geometric conditions ...................................................................................................................................................................................... 2
7 Optical standards ................................................................................................................................................................................................. 6
7.1 Reference standards ........................................................................................................................................................................... 6
7.1.1 Black glass ............................................................................................................................................................................. 6
7.1.2 Glass prism (for Method E only)......................................................................................................................... 6
7.2 Working standards .............................................................................................................................................................................. 7
7.2.1 Description .................. .................................................... ...................................................................................................... 7
7.2.2 Zero point check ............................................................................................................................................................... 7
8 Preparation and calibration of apparatus ................................................................................................................................. 7
9 Measurement of specular reflectance and specular gloss ........................................................................................ 8
9.1 General ........................................................................................................................................................................................................... 8
9.2 Measurement of specular reflectance ................................................................................................................................. 8
9.3 Measurement of specular gloss ................................................................................................................................................ 8
10 Expression of results .....................................................................................................................................................................................11
10.1 General ........................................................................................................................................................................................................11
10.2 Specular reflectance ........................................................................................................................................................................11
10.3 Specular gloss .......................................................................................................................................................................................11
11 Test report ................................................................................................................................................................................................................11
Annex A (normative) Specular reflectance and specular gloss of black glass ........................................................12
© ISO 2021 – All rights reserved iii---------------------- Page: 9 ----------------------
SIST EN ISO 7668:2021
ISO 7668:2021(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 of 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 www .iso .org/
iso/ foreword .html.This document was prepared by Technical Committee ISO/TC 79, Light metals and their alloys,
Subcommittee SC 2, Organic and anodic oxidation coatings on aluminium, in collaboration with the
European Committee for Standardization (CEN) Technical Committee CEN/TC 132, Aluminium and
aluminium alloys, in accordance with the Agreement on technical cooperation between ISO and CEN
(Vienna Agreement).This fourth edition cancels and replaces the third edition (ISO 7668:2018), which has been technically
revised. The main changes compared with the previous edition are as follows:— Tables 4 and 5 have been revised.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/ members .html.iv © ISO 2021 – All rights reserved
---------------------- Page: 10 ----------------------
SIST EN ISO 7668:2021
ISO 7668:2021(E)
Introduction
Specular reflectance and specular gloss are not unique physical properties of a surface. They vary with
the angle of measurement, and with the aperture dimensions that define the incident and the reflected
beams, such that measurements of these properties are not independent of the apparatus being used.
The specular reflectance of most surfaces increases with the angle of measurement and accounts for the
use of reflectometers with various angles as, for example, for painted surfaces. The specular reflectance
characteristics of anodized aluminium, however, do not always behave in the normal manner and,
because of its property of double reflection, reflected light comes partly from the film surface and
partly from the underlying metal. It is advisable to measure the specular reflectance characteristics at
20°, 45°, 60° and 85° to obtain a complete understanding of the specular reflectance properties of the
anodized surface, and careful thought should be given to which method or methods are most relevant
in any particular situation. The specular reflectance of bright-anodized aluminium with a mirror finish
is best measured using 45° or 20° geometry.© ISO 2021 – All rights reserved v
---------------------- Page: 11 ----------------------
SIST EN ISO 7668:2021
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SIST EN ISO 7668:2021
INTERNATIONAL STANDARD ISO 7668:2021(E)
Anodizing of aluminium and its alloys — Measurement of
specular reflectance and specular gloss of anodic oxidation
coatings at angles of 20°, 45°, 60° or 85°
1 Scope
This document specifies methods for the measurement of specular reflectance and specular gloss of
flat samples of anodized aluminium using geometries of 20° (Method A), 45° (Method B), 60° (Method
C) and 85° (Method D) and of specular reflectance by an additional 45° method (Method E) employing a
narrow acceptance angle.The methods described are intended mainly for use with clear anodized surfaces. They can be used
with colour-anodized aluminium, but only with similar colours.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 7583, Anodizing of aluminium and its alloys — Terms and definitionsISO/CIE 11664-1, Colorimetry — Part 1: CIE standard colorimetric observers
ISO 11664-2, Colorimetry — Part 2: CIE standard illuminants
CIE Publication No. 15, Colorimetry
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 7583 and the following apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp— IEC Electropedia: available at https:// www .electropedia .org/
3.1
specular reflectance
ratio of the luminous flux, reflected in the specular direction for a specified source and receptor angle,
to the luminous flux of the incident lightNote 1 to entry: Usually expressed as a percentage.
© ISO 2021 – All rights reserved 1
---------------------- Page: 13 ----------------------
SIST EN ISO 7668:2021
ISO 7668:2021(E)
3.2
specular gloss
ratio of the luminous flux, reflected from an object in the specular direction for a specified source
and receptor angle, to the luminous flux reflected from glass with a refractive index of 1,567 at a
wavelength of 546,1 nm (which is the central wavelength of the spectral luminous efficiency function)
in the specular directionNote 1 to entry: To set the specular gloss scale, polished black glass with a refractive index of 1,567 is assigned
the value of 100 for geometries of 20°, 45°, 60° and 85° (see Table 5). The phenomenon of light reflectance by
anodized aluminium is very different to that of black glass and the choice of a black-glass standard is arbitrary
and made to allow comparison of different qualities of anodized aluminium.4 Principle
The specular reflectance and specular gloss of anodized aluminium surfaces are measured under
defined conditions using, as required, geometries of 20°, 45°, 60° and 85°.5 Apparatus
The usual laboratory apparatus and, in particular, the following shall be used.
Approximate comparisons between surfaces of the same colour can be made, but an accurate
measurement requires the combination of light source, photoelectric cell and associated colour filters
...SLOVENSKI STANDARD
SIST EN ISO 7668:2021
01-november-2021
Nadomešča:
SIST EN ISO 7668:2018
Anodizacija aluminija in aluminijevih zlitin - Merjenje odbojnosti in sijaja
anodizirane plasti pod koti 20°, 45°, 60° ali 85° (ISO 7668:2021)
Anodizing of aluminium and its alloys - Measurement of specular reflectance and
specular gloss of anodic oxidation coatings at angles of 20°, 45°, 60° or 85° (ISO
7668:2021)Anodisieren von Aluminium und Aluminiumlegierungen - Messung des gerichteten
Reflexionsgrades und des Spiegelglanzes von anodisch erzeugten Oxidschichten bei
Winkeln von 20°, 45°, 60° oder 85° (ISO 7668:2021)
Anodisation de l'aluminium et de ses alliages - Mesurage des caractéristiques de
réflectivité et de brillant spéculaires des couches anodiques à angle fixe de 20°, 45°, 60°
ou 85° (ISO 7668:2021)Ta slovenski standard je istoveten z: EN ISO 7668:2021
ICS:
25.220.20 Površinska obdelava Surface treatment
77.120.10 Aluminij in aluminijeve zlitine Aluminium and aluminium
alloys
SIST EN ISO 7668:2021 de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
---------------------- Page: 1 ----------------------SIST EN ISO 7668:2021
---------------------- Page: 2 ----------------------
SIST EN ISO 7668:2021
EN ISO 7668
EUROPEAN STANDARD
NORME EUROPÉENNE
September 2021
EUROPÄISCHE NORM
ICS 25.220.20 Supersedes EN ISO 7668:2018
English Version
Anodizing of aluminium and its alloys - Measurement of
specular reflectance and specular gloss of anodic oxidation
coatings at angles of 20°, 45°, 60° or 85° (ISO 7668:2021)
Anodisation de l'aluminium et de ses alliages - Anodisieren von Aluminium und
Mesurage des caractéristiques de réflectivité et de Aluminiumlegierungen - Messung des gerichteten
brillant spéculaires des couches anodiques à angle fixe Reflexionsgrades und des Spiegelglanzes von anodisch
de 20°, 45°, 60° ou 85° (ISO 7668:2021) erzeugten Oxidschichten bei Winkeln von 20°, 45°, 60°
oder 85° (ISO 7668:2021)This European Standard was approved by CEN on 17 August 2021.
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
© 2021 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 7668:2021 E
worldwide for CEN national Members.---------------------- Page: 3 ----------------------
SIST EN ISO 7668:2021
EN ISO 7668:2021 (E)
Contents Page
European foreword ....................................................................................................................................................... 3
---------------------- Page: 4 ----------------------SIST EN ISO 7668:2021
EN ISO 7668:2021 (E)
European foreword
This document (EN ISO 7668:2021) has been prepared by Technical Committee ISO/TC 79 "Light
metals and their alloys" in collaboration with Technical Committee CEN/TC 132 “Aluminium and
aluminium alloys” the secretariat of which is held by AFNOR.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 March 2022, and conflicting national standards shall
be withdrawn at the latest by March 2022.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 7668:2018.Any feedback and questions on this document should be directed to the users’ national standards
body/national committee. A complete listing of these bodies can be found on the CEN websites.
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 7668:2021 has been approved by CEN as EN ISO 7668:2021 without any modification.
---------------------- Page: 5 ----------------------SIST EN ISO 7668:2021
---------------------- Page: 6 ----------------------
SIST EN ISO 7668:2021
INTERNATIONAL ISO
STANDARD 7668
Fourth edition
2021-08
Anodizing of aluminium and its
alloys — Measurement of specular
reflectance and specular gloss of
anodic oxidation coatings at angles of
20°, 45°, 60° or 85°
Anodisation de l'aluminium et de ses alliages — Mesurage des
caractéristiques de réflectivité et de brillant spéculaires des couches
anodiques à angle fixe de 20°, 45°, 60° ou 85°
Reference number
ISO 7668:2021(E)
ISO 2021
---------------------- Page: 7 ----------------------
SIST EN ISO 7668:2021
ISO 7668:2021(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2021
All rights reserved. Unless otherwise specified, or required in the context of its implementation, 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
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2021 – All rights reserved
---------------------- Page: 8 ----------------------
SIST EN ISO 7668:2021
ISO 7668:2021(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
6 Geometric conditions ...................................................................................................................................................................................... 2
7 Optical standards ................................................................................................................................................................................................. 6
7.1 Reference standards ........................................................................................................................................................................... 6
7.1.1 Black glass ............................................................................................................................................................................. 6
7.1.2 Glass prism (for Method E only)......................................................................................................................... 6
7.2 Working standards .............................................................................................................................................................................. 7
7.2.1 Description .................. .................................................... ...................................................................................................... 7
7.2.2 Zero point check ............................................................................................................................................................... 7
8 Preparation and calibration of apparatus ................................................................................................................................. 7
9 Measurement of specular reflectance and specular gloss ........................................................................................ 8
9.1 General ........................................................................................................................................................................................................... 8
9.2 Measurement of specular reflectance ................................................................................................................................. 8
9.3 Measurement of specular gloss ................................................................................................................................................ 8
10 Expression of results .....................................................................................................................................................................................11
10.1 General ........................................................................................................................................................................................................11
10.2 Specular reflectance ........................................................................................................................................................................11
10.3 Specular gloss .......................................................................................................................................................................................11
11 Test report ................................................................................................................................................................................................................11
Annex A (normative) Specular reflectance and specular gloss of black glass ........................................................12
© ISO 2021 – All rights reserved iii---------------------- Page: 9 ----------------------
SIST EN ISO 7668:2021
ISO 7668:2021(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 of 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 www .iso .org/
iso/ foreword .html.This document was prepared by Technical Committee ISO/TC 79, Light metals and their alloys,
Subcommittee SC 2, Organic and anodic oxidation coatings on aluminium, in collaboration with the
European Committee for Standardization (CEN) Technical Committee CEN/TC 132, Aluminium and
aluminium alloys, in accordance with the Agreement on technical cooperation between ISO and CEN
(Vienna Agreement).This fourth edition cancels and replaces the third edition (ISO 7668:2018), which has been technically
revised. The main changes compared with the previous edition are as follows:— Tables 4 and 5 have been revised.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/ members .html.iv © ISO 2021 – All rights reserved
---------------------- Page: 10 ----------------------
SIST EN ISO 7668:2021
ISO 7668:2021(E)
Introduction
Specular reflectance and specular gloss are not unique physical properties of a surface. They vary with
the angle of measurement, and with the aperture dimensions that define the incident and the reflected
beams, such that measurements of these properties are not independent of the apparatus being used.
The specular reflectance of most surfaces increases with the angle of measurement and accounts for the
use of reflectometers with various angles as, for example, for painted surfaces. The specular reflectance
characteristics of anodized aluminium, however, do not always behave in the normal manner and,
because of its property of double reflection, reflected light comes partly from the film surface and
partly from the underlying metal. It is advisable to measure the specular reflectance characteristics at
20°, 45°, 60° and 85° to obtain a complete understanding of the specular reflectance properties of the
anodized surface, and careful thought should be given to which method or methods are most relevant
in any particular situation. The specular reflectance of bright-anodized aluminium with a mirror finish
is best measured using 45° or 20° geometry.© ISO 2021 – All rights reserved v
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SIST EN ISO 7668:2021
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SIST EN ISO 7668:2021
INTERNATIONAL STANDARD ISO 7668:2021(E)
Anodizing of aluminium and its alloys — Measurement of
specular reflectance and specular gloss of anodic oxidation
coatings at angles of 20°, 45°, 60° or 85°
1 Scope
This document specifies methods for the measurement of specular reflectance and specular gloss of
flat samples of anodized aluminium using geometries of 20° (Method A), 45° (Method B), 60° (Method
C) and 85° (Method D) and of specular reflectance by an additional 45° method (Method E) employing a
narrow acceptance angle.The methods described are intended mainly for use with clear anodized surfaces. They can be used
with colour-anodized aluminium, but only with similar colours.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 7583, Anodizing of aluminium and its alloys — Terms and definitionsISO/CIE 11664-1, Colorimetry — Part 1: CIE standard colorimetric observers
ISO 11664-2, Colorimetry — Part 2: CIE standard illuminants
CIE Publication No. 15, Colorimetry
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 7583 and the following apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp— IEC Electropedia: available at https:// www .electropedia .org/
3.1
specular reflectance
ratio of the luminous flux, reflected in the specular direction for a specified source and receptor angle,
to the luminous flux of the incident lightNote 1 to entry: Usually expressed as a percentage.
© ISO 2021 – All rights reserved 1
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SIST EN ISO 7668:2021
ISO 7668:2021(E)
3.2
specular gloss
ratio of the luminous flux, reflected from an object in the specular direction for a specified source
and receptor angle, to the luminous flux reflected from glass with a refractive index of 1,567 at a
wavelength of 546,1 nm (which is the central wavelength of the spectral luminous efficiency function)
in the specular directionNote 1 to entry: To set the specular gloss scale, polished black glass with a refractive index of 1,567 is assigned
the value of 100 for geometries of 20°, 45°, 60° and 85° (see Table 5). The phenomenon of light reflectance by
anodized aluminium is very different to that of black glass and the choice of a black-glass standard is arbitrary
and made to allow comparison of different qualities of anodized aluminium.4 Principle
The specular reflectance and specular gloss of anodized aluminium surfaces are measured under
defined conditions using, as required, geometries of 20°, 45°, 60° and 85°.5 Apparatus
The usual laboratory apparatus and, in particular, the following shall be used.
Approximate comparisons between surfaces of the same colour can be made, but an accurate
measurement requires the combination of light source, photoelectric cell and associated colour filters
...SLOVENSKI STANDARD
oSIST prEN ISO 7668:2021
01-april-2021
Anodizacija aluminija in aluminijevih zlitin - Merjenje odbojnosti in sijaja
anodizirane plasti pod koti 20°, 45°, 60° ali 85° (ISO/DIS 7668:2021)
Anodizing of aluminium and its alloys - Measurement of specular reflectance and
specular gloss of anodic oxidation coatings at angles of 20 degrees, 45 degrees, 60
degrees or 85 degrees (ISO/DIS 7668:2021)Anodisieren von Aluminium und Aluminiumlegierungen - Messung des gerichteten
Reflexionsgrades und des Spiegelglanzes von anodisch erzeugten Oxidschichten bei
Winkeln von 20°, 45°, 60° oder 85° (ISO/DIS 7668:2021)
Anodisation de l'aluminium et de ses alliages - Mesurage des caractéristiques de
réflectivité et de brillant spéculaires des couches anodiques à angle fixe de 20 degrés,
45 degrés, 60 degrés ou 85 degrés (ISO/DIS 7668:2021)Ta slovenski standard je istoveten z: prEN ISO 7668
ICS:
25.220.20 Površinska obdelava Surface treatment
77.120.10 Aluminij in aluminijeve zlitine Aluminium and aluminium
alloys
oSIST prEN ISO 7668:2021 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
---------------------- Page: 1 ----------------------oSIST prEN ISO 7668:2021
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oSIST prEN ISO 7668:2021
DRAFT INTERNATIONAL STANDARD
ISO/DIS 7668
ISO/TC 79/SC 2 Secretariat: JISC
Voting begins on: Voting terminates on:
2021-02-23 2021-05-18
Anodizing of aluminium and its alloys — Measurement of
specular reflectance and specular gloss of anodic oxidation
coatings at angles of 20 degrees, 45 degrees, 60 degrees or
85 degrees
Anodisation de l'aluminium et de ses alliages — Mesurage des caractéristiques de réflectivité et de brillant
spéculaires des couches anodiques à angle fixe de 20 degrés, 45 degrés, 60 degrés ou 85 degrés
ICS: 25.220.20THIS DOCUMENT IS A DRAFT CIRCULATED
This document is circulated as received from the committee secretariat.
FOR COMMENT AND APPROVAL. IT IS
THEREFORE SUBJECT TO CHANGE AND MAY
NOT BE REFERRED TO AS AN INTERNATIONAL
STANDARD UNTIL PUBLISHED AS SUCH.
IN ADDITION TO THEIR EVALUATION AS
ISO/CEN PARALLEL PROCESSING
BEING ACCEPTABLE FOR INDUSTRIAL,
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
STANDARDS MAY ON OCCASION HAVE TO
BE CONSIDERED IN THE LIGHT OF THEIR
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
Reference number
NATIONAL REGULATIONS.
ISO/DIS 7668:2021(E)
RECIPIENTS OF THIS DRAFT ARE INVITED
TO SUBMIT, WITH THEIR COMMENTS,
NOTIFICATION OF ANY RELEVANT PATENT
RIGHTS OF WHICH THEY ARE AWARE AND TO
PROVIDE SUPPORTING DOCUMENTATION. ISO 2021
---------------------- Page: 3 ----------------------
oSIST prEN ISO 7668:2021
ISO/DIS 7668:2021(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2021
All rights reserved. Unless otherwise specified, or required in the context of its implementation, 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
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2021 – All rights reserved
---------------------- Page: 4 ----------------------
oSIST prEN ISO 7668:2021
ISO/DIS 7668:2021(E)
Contents Page
Foreword ........................................................................................................................................................................................................................................iv
Introduction ..................................................................................................................................................................................................................................v
1 Scope ................................................................................................................................................................................................................................. 1
2 Normative references ...................................................................................................................................................................................... 1
3 Terms and definitions ..................................................................................................................................................................................... 1
4 Principle ........................................................................................................................................................................................................................ 2
5 Apparatus and geometric conditions .............................................................................................................................................. 2
6 Optical standards ................................................................................................................................................................................................. 6
6.1 Reference standards ........................................................................................................................................................................... 6
6.1.1 Black glass ............................................................................................................................................................................. 6
6.1.2 Glass prism (for Method E only)......................................................................................................................... 7
6.2 Working standards .............................................................................................................................................................................. 7
6.2.1 Description .................. .................................................... ...................................................................................................... 7
6.2.2 Zero point check ............................................................................................................................................................... 7
7 Preparation and calibration of apparatus ................................................................................................................................. 7
8 Measurement of specular reflectance and specular gloss ........................................................................................ 8
8.1 General ........................................................................................................................................................................................................... 8
8.2 Measurement of specular reflectance ................................................................................................................................. 8
8.3 Measurement of specular gloss ................................................................................................................................................ 8
9 Expression of results .....................................................................................................................................................................................11
9.1 General ........................................................................................................................................................................................................11
9.2 Specular reflectance ........................................................................................................................................................................11
9.3 Specular gloss .......................................................................................................................................................................................11
10 Test report ................................................................................................................................................................................................................11
Annex A (normative) Specular reflectance and specular gloss of black glass ........................................................12
© ISO 2021 – All rights reserved iii---------------------- Page: 5 ----------------------
oSIST prEN ISO 7668:2021
ISO/DIS 7668:2021(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 of 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 www .iso .org/
iso/ foreword .html.This document was prepared by Technical Committee ISO/TC 79, Light metals and their alloys,
Subcommittee SC2, Organic and anodic oxidation coatings on aluminium.This fourth edition cancels and replaces the third edition (ISO 7668:2018), which has been technically
revised.The main changes compared to the previous edition are as follows:
— Table 4 and 5 are revised for correction
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/ members .html.iv © ISO 2021 – All rights reserved
---------------------- Page: 6 ----------------------
oSIST prEN ISO 7668:2021
ISO/DIS 7668:2021(E)
Introduction
Specular reflectance and specular gloss are not unique physical properties of a surface. They vary with
the angle of measurement, and with the aperture dimensions that define the incident and the reflected
beams, such that measurements of these properties are not independent of the apparatus being used.
The specular reflectance of most surfaces increases with the angle of measurement and accounts for the
use of reflectometers with various angles as, for example, for painted surfaces. The specular reflectance
characteristics of anodized aluminium, however, do not always behave in the normal manner and,
because of its property of double reflection, reflected light comes partly from the film surface and
partly from the underlying metal. It is advisable to measure the specular reflectance characteristics at
20°, 45°, 60° and 85° to obtain a complete understanding of the specular reflectance properties of the
anodized surface, and careful thought should be given to which method or methods are most relevant
in any particular situation. The specular reflectance of bright-anodized aluminium with a mirror finish
is best measured using 45° or 20° geometry.© ISO 2021 – All rights reserved v
---------------------- Page: 7 ----------------------
oSIST prEN ISO 7668:2021
---------------------- Page: 8 ----------------------
oSIST prEN ISO 7668:2021
DRAFT INTERNATIONAL STANDARD ISO/DIS 7668:2021(E)
Anodizing of aluminium and its alloys — Measurement of
specular reflectance and specular gloss of anodic oxidation
coatings at angles of 20 degrees, 45 degrees, 60 degrees or
85 degrees
1 Scope
This document specifies methods for the measurement of specular reflectance and specular gloss of
flat samples of anodized aluminium using geometries of 20° (Method A), 45° (Method B), 60° (Method
C) and 85° (Method D); and of specular reflectance by an additional 45° method (Method E) employing
a narrow acceptance angle.The methods described are intended mainly for use with clear anodized surfaces. They can be used
with colour-anodized aluminium, but only with similar colours.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 7583, Anodizing of aluminium and its alloys — Terms and definitionsISO 11664-1, Colorimetry — Part 1: CIE standard colorimetric observers
ISO 11664-2, Colorimetry — Part 2: CIE standard illuminants
CIE Publication No. 15, Colorimetry
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 7583 and the following apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp— IEC Electropedia: available at http:// www .electropedia .org/
3.1
specular reflectance
ratio of the luminous flux, reflected in the specular direction for a specified source and receptor angle,
to the luminous flux of the incident lightNote 1 to entry: Normally expressed as a percentage.
© ISO 2021 – All rights reserved 1
---------------------- Page: 9 ----------------------
oSIST prEN ISO 7668:2021
ISO/DIS 7668:2021(E)
3.2
specular gloss
ratio of the luminous flux, reflected from an object in the specular direction for a specified source
and receptor angle, to the luminous flux reflected from glass with a refractive index of 1,567 at a
wavelength of 546,1 nm (which is the central wavelength of the spectral luminous efficiency function)
in the specular directionNote 1 to entry: To set the specular gloss scale, polished black glass with a refractive index of 1,567 is assigned
the value of 100 for geometries of 20°, 45°, 60° and 85° (see Table 5). The phenomenon of light reflectance by
anodized aluminium is very different to that of black glass and the choice of a black-glass standard is arbitrary
and made to allow comparison of different qualities of anodized aluminium.4 Principle
The specular reflectance and specular gloss of anodized aluminium surfaces are measured under
defined conditions using, as required, geometries of 20°, 45°, 60° and 85°.5 Apparatus and geometric conditions
Usual laboratory apparatus and in particular the following.
5.1 General. Approximate comparisons between surfaces of the same colour can be made, but an
accurate measurement requires the combination of light source, photoelectric cell and associated colour
filters to give a spectral sensitivity, approximating to the CIE spectral luminous efficiency, V(λ), weighted
for CIE standard illuminants C or D65. V(λ) shall conform to the requirements of ISO 11664 1. CIE
standard illuminants C and D65 shall conform to the requirements of CIE 15 and ISO 11664 2.
NOTE Since specular reflection is in general spectrally non-selective, the spectral characteristics of the light
source (5.2) and the receptor (5.4) do not affect the measurement of normal uncoloured anodized surfaces.
5.2 Polychromatic light source and housing, with a lens that directs a parallel, or very slightly
converging, beam of light onto the surface under test.5.3 Means for locating the specimen surface, in the correct position for measurement.
5.4 Receptor housing containing a lens, a receptor aperture and a photoelectric cell, to receive
the cone of reflected light.5.5 Sensitivity control, for setting the photocell current to any desired value on the instrument scale
or digital indicator.5.6 Receptor meter, capable of giving an indication proportional to the light flux passing the receptor
aperture within 1 % of the full-scale reading. Spectral corrections are not usually required (see Note to 5.1).
5.7 Geometric conditionsThe incident angle, ε , which is the angle between the axis of the incident beam and the perpendicular
to the surface under test, shall have the following values and tolerances:— for Method A: 20° ± 0,1°;
— for Method B: 45° ± 0,1°;
— for Method C: 60° ± 0,1°;
— for Method D: 85° ± 0,1°;
2 © ISO 2021 – All rights reserved
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oSIST prEN ISO 7668:2021
ISO/DIS 7668:2021(E)
— for Method E: 45° ± 0,1°.
There shall be no vignetting of rays that lie within the angles specified above.
The axis of the receptor shall, as far as possible, coincide with the mirror image of the axis of the incident
beam; the receptor angle, ε , whi...
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