Tissue paper and tissue products - Part 7: Determination of optical properties - Measurement of brightness and colour with D65/10° (outdoor daylight) (ISO 12625-7:2021)

Tissue-Papier und Tissue-Produkte - Teil 7: Bestimmung der optischen Eigenschaften - Brightness- und Farbmessung mit Lichtart D65/10° (Außentageslicht) (ISO 12625-7:2021)

Dieses Dokument legt Prüfverfahren für die instrumentelle Bestimmung von Brightness und Farbe für Tissue-Papier und Tissue-Produkte unter Tageslichtbedingungen fest. Es werden auch genaue Anweisungen für die Vorbereitung von Messproben (einlagige, mehrlagige Produkte) und für die optischen Messungen von Produkten gegeben, bei denen besondere Vorsichtsmaßnahmen notwendig sein können.
ANMERKUNG Die als ISO-Brightness und -Farbe mit Lichtart C/2° (Tageslichtbedingungen in Innenräumen) bezeichneten Eigenschaften werden mit einem Gerät gemessen, das auf einen viel geringeren UV-Anteil angepasst ist, als in diesem Dokument festgelegt wird. Die Messungen von ISO-Brightness und -Farbe mit Lichtart C/2° (Tageslichtbedingungen in Innenräumen) werden in ISO 12625-15 beschrieben.

Papier tissue et produits tissue - Partie 7: Détermination des propriétés optiques - Mesurage du degré de blancheur et de la couleur en D65/10° (lumière du jour extérieure) (ISO 12625-7:2021)

Tissue papir in izdelki iz tissue papirja - 7. del: Določevanje optičnih lastnosti - Merjenje beline in barve z D65/10° (zunanja dnevna svetloba) (ISO 12625-7:2021)

General Information

Status
Published
Public Enquiry End Date
19-Nov-2020
Publication Date
11-Oct-2021
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
29-Sep-2021
Due Date
04-Dec-2021
Completion Date
12-Oct-2021

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SLOVENSKI STANDARD
SIST EN ISO 12625-7:2021
01-november-2021
Nadomešča:
SIST EN ISO 12625-7:2014

Tissue papir in izdelki iz tissue papirja - 7. del: Določevanje optičnih lastnosti -

Merjenje beline in barve z D65/10° (zunanja dnevna svetloba) (ISO 12625-7:2021)
Tissue paper and tissue products - Part 7: Determination of optical properties -
Measurement of brightness and colour with D65/10° (outdoor daylight) (ISO 12625-
7:2021)

Tissue-Papier und Tissue-Produkte - Teil 7: Bestimmung der optischen Eigenschaften -

Brightness- und Farbmessung mit Lichtart D65/10° (Außentageslicht) (ISO 12625-
7:2021)

Papier tissue et produits tissue - Partie 7: Détermination des propriétés optiques -

Mesurage du degré de blancheur et de la couleur en D65/10° (lumière du jour
extérieure) (ISO 12625-7:2021)
Ta slovenski standard je istoveten z: EN ISO 12625-7:2021
ICS:
17.180.20 Barve in merjenje svetlobe Colours and measurement of
light
85.080.20 Tissue papir Tissue paper
SIST EN ISO 12625-7:2021 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
SIST EN ISO 12625-7:2021
---------------------- Page: 2 ----------------------
SIST EN ISO 12625-7:2021
EN ISO 12625-7
EUROPEAN STANDARD
NORME EUROPÉENNE
September 2021
EUROPÄISCHE NORM
ICS 85.080.20 Supersedes EN ISO 12625-7:2014
English Version
Tissue paper and tissue products - Part 7: Determination
of optical properties - Measurement of brightness and
colour with D65/10° (outdoor daylight) (ISO 12625-
7:2021)

Papier tissue et produits tissue - Partie 7: Tissue-Papier und Tissue-Produkte - Teil 7:

Détermination des propriétés optiques - Mesurage du Bestimmung der optischen Eigenschaften - Brightness-

degré de blancheur et de la couleur en D65/10° und Farbmessung mit Lichtart D65/10°

(lumière du jour extérieure) (ISO 12625-7:2021) (Außentageslicht) (ISO 12625-7:2021)

This European Standard was approved by CEN on 14 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 12625-7:2021 E

worldwide for CEN national Members.
---------------------- Page: 3 ----------------------
SIST EN ISO 12625-7:2021
EN ISO 12625-7:2021 (E)
Contents Page

European foreword ....................................................................................................................................................... 3

---------------------- Page: 4 ----------------------
SIST EN ISO 12625-7:2021
EN ISO 12625-7:2021 (E)
European foreword

This document (EN ISO 12625-7:2021) has been prepared by Technical Committee ISO/TC 6 "Paper,

board and pulps" in collaboration with Technical Committee CEN/TC 172 “Pulp, paper and board” 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 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 12625-7:2014.

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 12625-7:2021 has been approved by CEN as EN ISO 12625-7:2021 without any

modification.
---------------------- Page: 5 ----------------------
SIST EN ISO 12625-7:2021
---------------------- Page: 6 ----------------------
SIST EN ISO 12625-7:2021
INTERNATIONAL ISO
STANDARD 12625-7
Third edition
2021-08
Tissue paper and tissue products —
Part 7:
Determination of optical properties —
Measurement of brightness and colour
with D65/10° (outdoor daylight)
Papier tissue et produits tissue —
Partie 7: Détermination des propriétés optiques — Mesurage du
degré de blancheur et de la couleur en D65/10° (lumière du jour
extérieure)
Reference number
ISO 12625-7:2021(E)
ISO 2021
---------------------- Page: 7 ----------------------
SIST EN ISO 12625-7:2021
ISO 12625-7:2021(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 12625-7:2021
ISO 12625-7:2021(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

Introduction ..................................................................................................................................................................................................................................v

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 1

4 Principle ........................................................................................................................................................................................................................ 3

5 Apparatus ..................................................................................................................................................................................................................... 3

6 Calibration .................................................................................................................................................................................................................. 4

7 Sampling ........................................................................................................................................................................................................................ 5

8 Conditioning .............................................................................................................................................................................................................. 5

9 Preparation of test pieces ........................................................................................................................................................................... 5

10 Procedure..................................................................................................................................................................................................................... 5

10.1 General ........................................................................................................................................................................................................... 5

10.2 Measurement of D65 brightness ............................................................................................................................................. 5

10.3 Measurement of colour (D65/10°) ........................................................................................................................................ 6

11 Calculation .................................................................................................................................................................................................................. 6

11.1 D65 brightness ........................................................................................................................................................................................ 6

11.2 Colour (D65/10°) ................................................................................................................................................................................. 6

11.2.1 Single value ........................................................................................................................................................................... 6

11.2.2 Mean value ............................................................................................................................................................................ 7

11.2.3 Dispersion of the results ........................................................................................................................................... 7

12 Test report ................................................................................................................................................................................................................... 7

Annex A (informative) Precision ............................................................................................................................................................................... 9

Bibliography .............................................................................................................................................................................................................................12

© ISO 2021 – All rights reserved iii
---------------------- Page: 9 ----------------------
SIST EN ISO 12625-7:2021
ISO 12625-7:2021(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 6, Paper, board and pulps, Subcommittee

SC 2, Test methods and quality specifications for paper and board, in collaboration with the European

Committee for Standardization (CEN) Technical Committee CEN/TC 172, Pulp, paper and board, in

accordance with the Agreement on technical cooperation between ISO and CEN (Vienna Agreement).

This third edition cancels and replaces the second edition (ISO 12625-7:2014), which has been

technically revised.
The main changes compared to the previous edition are as follows:

— alternative formulae in 11.2.1 have been removed because they were not relevant for tissue paper.

A list of all parts in the ISO 12625 series can be found on the ISO website.

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 12625-7:2021
ISO 12625-7:2021(E)
Introduction

Brightness and colour measurement can be performed under various illumination and observation

conditions. This document deals with D65/10° conditions, which refer to an outdoor daylight.

C/2° conditions (indoor daylight) are considered in ISO 12625-15. Although both International

Standards deal with brightness and colour, results obtained are usually different and do not correlate.

Optical measurement is affected by the geometry of the instruments used and by the texture of the

material. The design of the instrument to use according to this document and the routine to adopt for

its calibration are specified in ISO 2469 and ISO 11475.

The optical properties are related to the visual appearance of the material. Therefore, although optical

properties are intrinsic properties of tissue paper, they are not functional properties.

Brightness should not be confused with the optical property called CIE whiteness, which is based on

reflectance data obtained over the full visible spectral range (VIS) in contrast to the measurement of

brightness, which is limited to the blue region of VIS.

Due to its importance for some countries, three different test methods for the determination of optical

properties were developed:
— this document, i.e. ISO 12625-7;
— ISO 12625-15;
— ISO 12625-16.
© ISO 2021 – All rights reserved v
---------------------- Page: 11 ----------------------
SIST EN ISO 12625-7:2021
---------------------- Page: 12 ----------------------
SIST EN ISO 12625-7:2021
INTERNATIONAL STANDARD ISO 12625-7:2021(E)
Tissue paper and tissue products —
Part 7:
Determination of optical properties — Measurement of
brightness and colour with D65/10° (outdoor daylight)
1 Scope

This document specifies testing procedures for the instrumental determination of brightness and

colour of tissue paper and tissue products viewed under outdoor daylight conditions. It also gives

specific instructions for the preparation of test pieces (single-ply, multi-ply products) and for the optical

measurements of products, where special precautions can be necessary.

NOTE The properties called ISO brightness and colour with C/2° (indoor daylight) are measured with an

instrument adjusted to a much lower UV content than that specified in this document. The measurements of ISO

brightness and colour with C/2° (indoor daylight) are described in ISO 12625-15.
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 186, Paper and board — Sampling to determine average quality

ISO 187, Paper, board and pulps — Standard atmosphere for conditioning and testing and procedure for

monitoring the atmosphere and conditioning of samples

ISO 2469, Paper, board and pulps — Measurement of diffuse radiance factor (diffuse reflectance factor)

ISO 4094, Paper, board and pulps — General requirements for the competence of laboratories authorized

for the issue of optical reference transfer standards of level 3

ISO 11475:2017, Paper and board — Determination of CIE whiteness, D65/10 degrees (outdoor daylight)

ISO/CIE 11664-4, Colorimetry — Part 4: CIE 1976 L*a*b* colour space
3 Terms and definitions
For the purposes of this document, the following terms and definitions 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
diffuse radiance factor

ratio of the radiation reflected and emitted from a body to that reflected from the perfect reflecting

diffuser under the same conditions of diffuse illumination and normal detection
Note 1 to entry: The ratio is often expressed as a percentage.
© ISO 2021 – All rights reserved 1
---------------------- Page: 13 ----------------------
SIST EN ISO 12625-7:2021
ISO 12625-7:2021(E)
[SOURCE: ISO 2469:2014, 3.2]
3.2
intrinsic diffuse radiance factor

diffuse radiance factor (3.1) of a layer or pad of material thick enough to be opaque, i.e. such that

increasing the thickness of the pad by doubling the number of sheets results in no change in the

measured radiance factor

Note 1 to entry: The radiance factor of a single non-opaque sheet is dependent on the background and is not a

material property.
Note 2 to entry: The ratio is often expressed as a percentage.
[SOURCE: ISO 2469:2014, 3.3]
3.3
reflectance factor

quotient of the flux reflected in the directions by a given cone with apex at a surface element and the

flux reflected in the same directions by a perfect reflecting diffuser identically irradiated or illuminated

Note 1 to entry: The ratio is often expressed as a percentage.

Note 2 to entry: This term shall be used only when it is known that the test material exhibits no luminescence

(fluorescence).
[SOURCE: CIE S 017 ILV: 2020, 17-24-070]
3.4
D65 brightness

intrinsic diffuse radiance factor (3.2) measured with a reflectometer having the characteristics described

in ISO 2469, equipped with a filter or corresponding function having an effective wavelength of 457 nm

(and a half bandwidth of 44 nm), and adjusted so that the UV content of the irradiation incident upon

the test piece corresponds to that of the CIE standard illuminant D65

Note 1 to entry: The filter function is described more fully by the weighting factors given in ISO 2470-2.

3.5
tristimulus values
X ,Y ,Z
10 10 10

amounts of the reference colour stimuli, in a given trichromatic system, required to match the colour of

the stimulus considered

Note 1 to entry: In ISO 5631-2 the CIE standard illuminant D65 and the CIE 1964 (10°) standard observer are

...

SLOVENSKI STANDARD
oSIST prEN ISO 12625-7:2020
01-november-2020

Tissue papir in izdelki iz tissue papirja - 7. del: Določevanje optičnih lastnosti -

Merjenje svetlosti in barve z D65/10° (zunanja dnevna svetloba) (ISO/DIS 12625-
7:2020)
Tissue paper and tissue products - Part 7: Determination of optical properties -

Measurement of brightness and colour with D65/10° (outdoor daylight) (ISO/DIS 12625-

7:2020)

Tissue-Papier und Tissue-Produkte - Teil 7: Bestimmung der optischen Eigenschaften -

Brightness- und Farbmessung mit Lichtart D65/10° (Außentageslicht) (ISO/DIS 12625-

7:2020)

Papier tissue et produits tissue - Partie 7: Détermination des propriétés optiques -

Mesurage du degré de blancheur et de la couleur avec l'illuminant D65/10° (lumière du

jour extérieure) (ISO/DIS 12625-7:2020)
Ta slovenski standard je istoveten z: prEN ISO 12625-7
ICS:
17.180.20 Barve in merjenje svetlobe Colours and measurement of
light
85.080.20 Tissue papir Tissue paper
oSIST prEN ISO 12625-7:2020 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
oSIST prEN ISO 12625-7:2020
---------------------- Page: 2 ----------------------
oSIST prEN ISO 12625-7:2020
DRAFT INTERNATIONAL STANDARD
ISO/DIS 12625-7
ISO/TC 6/SC 2 Secretariat: SIS
Voting begins on: Voting terminates on:
2020-09-08 2020-12-01
Tissue paper and tissue products —
Part 7:
Determination of optical properties — Measurement of
brightness and colour with D65/10° (outdoor daylight)
Papier tissue et produits tissue —

Partie 7: Détermination des propriétés optiques — Mesurage du degré de blancheur et de la couleur avec

l'illuminant D65/10° (lumière du jour extérieure)
ICS: 85.080.20
THIS DOCUMENT IS A DRAFT CIRCULATED
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
BEING ACCEPTABLE FOR INDUSTRIAL,
This document is circulated as received from the committee secretariat.
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 12625-7:2020(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 2020
---------------------- Page: 3 ----------------------
oSIST prEN ISO 12625-7:2020
ISO/DIS 12625-7:2020(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2020

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 2020 – All rights reserved
---------------------- Page: 4 ----------------------
oSIST prEN ISO 12625-7:2020
ISO/DIS 12625-7:2020(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

Introduction ..................................................................................................................................................................................................................................v

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 1

4 Principle ........................................................................................................................................................................................................................ 3

5 Apparatus ..................................................................................................................................................................................................................... 3

6 Calibration .................................................................................................................................................................................................................. 4

7 Sampling ........................................................................................................................................................................................................................ 5

8 Conditioning .............................................................................................................................................................................................................. 5

9 Preparation of test pieces ........................................................................................................................................................................... 5

10 Procedure..................................................................................................................................................................................................................... 5

10.1 General ........................................................................................................................................................................................................... 5

10.2 Measurement of D65 brightness ............................................................................................................................................. 6

10.3 Measurement of colour (D65/10°) ........................................................................................................................................ 6

11 Calculation .................................................................................................................................................................................................................. 6

11.1 D65 brightness ........................................................................................................................................................................................ 6

11.2 Colour (D65/10°) ................................................................................................................................................................................. 6

12 Test report ................................................................................................................................................................................................................... 7

Annex A (informative) Precision ............................................................................................................................................................................... 9

Bibliography .............................................................................................................................................................................................................................12

© ISO 2020 – All rights reserved iii
---------------------- Page: 5 ----------------------
oSIST prEN ISO 12625-7:2020
ISO/DIS 12625-7:2020(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 6, Paper, board and pulps, Subcommittee

SC 2, Test methods and quality specifications for paper and board.

This third edition cancels and replaces the second edition (ISO 12625-7:2014), which has been

technically revised.
The main changes compared to the previous edition are as follows:

— removing alternative equations in clause 11.2.1 because they are not relevant for tissue paper.

A list of all parts in the ISO 12625 series can be found on the ISO website.

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 2020 – All rights reserved
---------------------- Page: 6 ----------------------
oSIST prEN ISO 12625-7:2020
ISO/DIS 12625-7:2020(E)
Introduction

Brightness and colour measurement may be performed under various illumination and observation

conditions. This part of ISO 12625 deals with D65/10° conditions, which refer to an outdoor daylight.

C/2° conditions (indoor daylight) are considered in ISO 12625-15. Although both international

standards deal with brightness and colour, results obtained are usually different and do not correlate.

Optical measurement is affected by the geometry of the instruments used and by the texture of the

material. The design of the instrument to be used according to this part of ISO 12625, and the routine to

be adopted for its calibration, are specified in ISO 2469 and ISO 11475.

The optical properties are related to the visual appearance of the material. Therefore, although optical

properties are intrinsic properties of tissue paper, they are not functional properties.

Brightness shall not be confused with the optical property called CIE-whiteness that is based on

reflectance data obtained over the full visible spectral range (VIS) in contrast to the measurement of

brightness which is limited to the blue region of VIS.

Due to the importance for some countries three different test methods for the determination of optical

properties were developed:

— Part 7: Determination of optical properties — Measurement of brightness and colour with D65/10°

(outdoor daylight);

— Part 15: Determination of optical properties — Measurement of brightness and colour with C/2°

(indoor) daylight;

— Part 16: Determination of optical properties — Opacity (paper backing) — Diffuse reflectance method.

© ISO 2020 – All rights reserved v
---------------------- Page: 7 ----------------------
oSIST prEN ISO 12625-7:2020
---------------------- Page: 8 ----------------------
oSIST prEN ISO 12625-7:2020
DRAFT INTERNATIONAL STANDARD ISO/DIS 12625-7:2020(E)
Tissue paper and tissue products —
Part 7:
Determination of optical properties — Measurement of
brightness and colour with D65/10° (outdoor daylight)
1 Scope

This document specifies testing procedures for the instrumental determination of brightness and

colour of tissue paper and tissue products viewed under outdoor daylight conditions. It also gives

specific instructions for the preparation of test pieces (single-ply, multi-ply products) and for the optical

measurements of products, where special precautions may be necessary.

NOTE The properties called ISO brightness and colour with C/2° (indoor daylight) are measured with an

instrument adjusted to a much lower UV content than that specified in this document. The measurements of ISO

brightness and colour with C/2° (indoor daylight) are described in ISO 12625-15.
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 186, Paper and board — Sampling to determine average quality

ISO 187, Paper, board and pulps — Standard atmosphere for conditioning and testing and procedure for

monitoring the atmosphere and conditioning of samples

ISO 2469, Paper, board and pulps — Measurement of diffuse radiance factor (diffuse reflectance factor)

ISO 2470-2, Paper, board and pulps — Measurement of diffuse blue reflectance factor — Part 2: Outdoor

daylight conditions (D65 brightness)

ISO 4094, Paper, board and pulps — General requirements for the competence of laboratories authorized

for the issue of optical reference transfer standards of level 3

ISO 5631-2, Paper and board — Determination of colour by diffuse reflectance — Part 2: Outdoor daylight

conditions (D65/10 degrees)

ISO 11475, Paper and board — Determination of CIE whiteness, D65/10 degrees (outdoor daylight)

3 Terms and definitions
For the purposes of this document, the following terms and definitions 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/
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3.1
diffuse radiance factor

ratio of the radiation reflected and emitted from a body to that reflected from the perfect reflecting

diffuser under the same conditions of diffuse illumination and normal detection
Note 1 to entry: The reflectance factor is expressed as a percentage.
[SOURCE: ISO 2469:2014, definition 3.2]
3.2
intrinsic diffuse radiance factor

diffuse radiance factor of a layer or pad of material thick enough to be opaque, i.e. such that increasing

the thickness of the pad by doubling the number of sheets results in no change in the measured radiance

factorNote 1to entry: The ratio is often expressed as a percentage.

Note 1 to entry: The radiance factor of a single non-opaque sheet is dependent on the background and is not a

material property.
[SOURCE: ISO 2469:2014, definition 3.3]
3.3
reflectance factor

ratio of the radiation reflected by a surface element of a body in the direction delimited by a given cone

with its apex at the surface element to that reflected by the perfect reflecting diffuser under the same

conditions of illumination
Note 1 to entry: The ratio is often expressed as a percentage.

Note 2 to entry: This term may be used only when it is known that the test material exhibits no luminescence

(fluorescence).
[SOURCE: ISO 2469:2014, definition 3.4]
3.4
D65 brightness

intrinsic reflectance factor measured with a reflectometer having the characteristics described in

ISO 2469, equipped with a filter or corresponding function having an effective wavelength of 457 nm

(and a half bandwidth of 44 nm), and adjusted so that the UV content of the irradiation incident upon

the test piece corresponds to that of the CIE standard illuminant D65

Note 1 to entry: The filter function is described more fully by the weighing function factors given in ISO 2470-2.

3.5
tristimulus values
X ,Y ,Z
10 10 10

amounts of the three reference colour stimuli, in a given chromatic system, required to match the

stimulus considered

Note 1 to entry: In ISO 5631-2 the CIE standard illuminant D65 and the CIE 1964 (10°) standard observer are

used to define the trichromatic system.

Note 2 to entry: The subscript 10 is applied to conform to the CIE convention that tristimulus units have the

subscript 10 when the CIE 1964 (10°) standard observer is used.
[SOURCE: ISO 5631-2:2015, definition 3.5]
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3.6
colour (D65/10°)

L*, a* and b* values of the sample according to the CIELAB 1976 system, corresponding to the CIE

[3]

standard illuminant D65, described in ISO 11664-2 and the CIE 1964 supplementary standard

[2]

colorimetric observer, described in ISO 11664-1, determined by measurement under the conditions

specified in ISO 5631-2

Note 1 to entry: The quantity L* is a measure of the lightness of the test piece, where L* = 0 corresponds to black

and L* = 100 is defined by the perfect reflecting diffuser. Visually, the quantities a* and b* represent respectively

the red-green and yellow-blue axes in colour space, such that
— +a* is a measure of the degree of redness of the test piece;
— -a* is a measure of the degree of greenness of the test piece;
— +b* is a measure of the degree of yellowness of the test piece;
— -b* is a measure of the degree of blueness of the test piece;
— if both a* and b* are equal to zero, the test piece is grey.
4 Principle

A test piece is illuminated diffusely in a standardized instrument and the light reflected normal to the

surface is either allowed to pass through a defined optical filter and then measured by a photodetector

or measured by an array of photosensitive diodes, where e
...

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