SIST ISO 9416:2011
Paper -- Determination of light scattering and absorption coefficients (using Kubelka-Munk theory)
Paper -- Determination of light scattering and absorption coefficients (using Kubelka-Munk theory)
This International Standard specifies a method for the calculation of light-scattering and light-absorption coefficients based upon diffuse reflectance measurements made under the conditions specified in ISO 2469 using the colour matching function y( ) and CIE illuminant C.
It is emphasized that the strict evaluation of the light-scattering and light-absorption coefficients requires conditions which cannot be achieved with the instrumentation specified here. The values obtained by application of this International Standard are dependent on the application of the Kubelka-Munk equations, not to full reflectance data but to reflectance factor data obtained using the specified d/0° geometry and a gloss trap.
The use of the method is restricted to white and near-white uncoated papers with an opacity less than about 95 %. Paper that has been treated with a fluorescent dyestuff or that exhibits significant fluorescence can only be dealt with if a filter with a cut-off wavelength of 420 nm is used to eliminate all the fluorescence effect in the UVex(420) mode.
NOTE 1 The residual UV-level in the instrument may depend on whether the instrument is adjusted to UV(C) or UV(D65) conditions prior to switching to the UVex(420) mode, but it is considered that this uncertainty in the residual level can be ignored in the application of this International Standard.
NOTE 2 Although this method is restricted to paper, it can be applied to pulp sheets, although this is not in accordance with this International Standard. In general, when pulps are tested, the light-absorption coefficient at 457 nm corresponding to the ISO brightness value or the spectral absorption coefficients are of greater interest than the weighted value standardized in this International Standard.
Papier -- Détermination des coefficients de diffusion et d'absorption de la lumière (utilisation de la théorie de Kubelka-Munk)
Papir - Določanje koeficienta sipanja in koeficienta absorpcije svetlobe (uporaba teorije po Kubelka-Munku)
Ta mednarodni standard opredeljuje metodo za izračun koeficienta sipanja in koeficienta absorpcije svetlobe, ki temelji na meritvah razpršene odsevnosti, narejenih v skladu s pogoji, opredeljenimi v ISO 2469, z uporabo funkcije barvnega usklajevanja y( ) in vrste svetlobe CIE C.
Poudarja, da strogo ocenjevanje koeficienta sipanja in koeficienta absorpcije svetlobe zahteva pogoje, ki jih ni mogoče doseči z merilnimi napravami, opredeljenimi v tem dokumentu. Vrednosti, pridobljene z uporabo tega mednarodnega standarda, so odvisne od uporabe enačb po Kubelka-Munku, ne za popolne podatke o odbojnosti, ampak za podatke o faktorju odbojnosti, pridobljene z uporabo opredeljene geometrije d/0° in pasti za sijaj.
Uporaba metode je omejena na bele in skoraj bele nepremazane papirje z opaciteto manj kot približno 95 %. Papir, ki je bil obdelan s fluorescenčnim barvilom ali ki kaže izrazito fluorescenco, se lahko obravnava le, če se uporabi filter z mejno valovno dolžino 420 nm, za izločitev vseh fluorescenčnih učinkov v načinu UVex(420).
OPOMBA 1: Preostala raven UV v instrumentu je lahko odvisna od tega, ali je instrument prilagojen pogojem UV(C) ali UV(D65) pred preklopom na način UVex(420), vendar se šteje, da se ta negotovost v preostali ravni lahko zanemari pri uporabi tega mednarodnega standarda.
OPOMBA 2: Čeprav je ta metoda omejena na papir, jo je mogoče uporabiti za pole vlaknin, čeprav to ni v skladu s tem mednarodnim standardom. Na splošno pri preskušanju vlaknin velja, da je koeficient absorpcije svetlobe pri 457 nm, ki ustreza vrednosti beline po ISO, ali koeficienti spektralne absorpcije zanimivejši kot tehtana vrednost, ki je standardizirana v tem mednarodnem standardu.
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INTERNATIONAL ISO
STANDARD 9416
Second edition
2009-05-01
Paper — Determination of light scattering
and absorption coefficients (using
Kubelka-Munk theory)
Papier — Détermination des coefficients de diffusion et d'absorption de
la lumière (utilisation de la théorie de Kubelka-Munk)
Reference number
ISO 9416:2009(E)
©
ISO 2009
---------------------- Page: 1 ----------------------
ISO 9416:2009(E)
PDF disclaimer
This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but
shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In
downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat
accepts no liability in this area.
Adobe is a trademark of Adobe Systems Incorporated.
Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation
parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In
the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below.
COPYRIGHT PROTECTED DOCUMENT
© ISO 2009
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,
electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or
ISO's member body in the country of the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2009 – All rights reserved
---------------------- Page: 2 ----------------------
ISO 9416:2009(E)
Contents Page
Foreword. iv
Introduction . v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions. 2
4 Principle. 3
5 Apparatus . 3
6 Sampling and conditioning. 4
7 Preparation of test pieces. 4
8 Procedure . 4
9 Calculation of results . 5
10 Precision. 5
11 Test report . 6
Annex A (informative) Spectral characteristics of reflectometers for measuring luminance factor. 7
Bibliography . 9
© ISO 2009 – All rights reserved iii
---------------------- Page: 3 ----------------------
ISO 9416:2009(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.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
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.
ISO 9416 was prepared by Technical Committee ISO/TC 6, Paper, board and pulps.
This second edition cancels and replaces the first edition (ISO 9416:1998), of which it constitutes a technical
revision.
iv © ISO 2009 – All rights reserved
---------------------- Page: 4 ----------------------
ISO 9416:2009(E)
Introduction
The opacity of a paper is dependent on its grammage, but it is also intrinsically dependent on the light-
absorption and light-scattering coefficients of the material. These coefficients are calculated from the values of
the reflectance factor over a black backing, the intrinsic reflectance factor and the grammage of the sheet.
The calculation of these coefficients requires luminance factor data obtained by measurement under specified
conditions. Apart from the optical properties of the sample, the luminance factor depends on the conditions of
measurement and particularly on the spectral and geometric characteristics of the instrument used for its
determination. This International Standard should therefore be read in conjunction with ISO 2469 and
ISO 2471.
NOTE This method is based on a theory developed by Kubelka and Munk. This theory describes scattering and
absorption processes with certain approximations and simplifications and can therefore yield questionable results in
extreme cases. However, the Kubelka-Munk theory offers a simple method for determining these coefficients with the
instrument used for the determination of optical properties of paper and pulps. Moreover, the method based on this theory
has been successfully used in practical applications.
© ISO 2009 – All rights reserved v
---------------------- Page: 5 ----------------------
INTERNATIONAL STANDARD ISO 9416:2009(E)
Paper — Determination of light scattering and absorption
coefficients (using Kubelka-Munk theory)
1 Scope
This International Standard specifies a method for the calculation of light-scattering and light-absorption
coefficients based upon diffuse reflectance measurements made under the conditions specified in ISO 2469
using the colour matching function y(λ) and CIE illuminant C.
It is emphasized that the strict evaluation of the light-scattering and light-absorption coefficients requires
conditions which cannot be achieved with the instrumentation specified here. The values obtained by
application of this International Standard are dependent on the application of the Kubelka-Munk equations, not
to full reflectance data but to reflectance factor data obtained using the specified d/0° geometry and a gloss
trap.
The use of the method is restricted to white and near-white uncoated papers with an opacity less than about
95 %. Paper that has been treated with a fluorescent dyestuff or that exhibits significant fluorescence can only
be dealt with if a filter with a cut-off wavelength of 420 nm is used to eliminate all the fluorescence effect in the
UVex(420) mode.
NOTE 1 The residual UV-level in the instrument may depend on whether the instrument is adjusted to UV(C) or
UV(D65) conditions prior to switching to the UVex(420) mode, but it is considered that this uncertainty in the residual level
can be ignored in the application of this International Standard.
NOTE 2 Although this method is restricted to paper, it can be applied to pulp sheets, although this is not in accordance
with this International Standard. In general, when pulps are tested, the light-absorption coefficient at 457 nm
corresponding to the ISO brightness value or the spectral absorption coefficients are of greater interest than the weighted
value standardized in this International Standard.
2 Normative references
The following referenced documents are indispensable for the application 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 536, Paper and board — Determination of grammage
ISO 2469, Paper, board and pulps — Measurement of diffuse radiance factor
ISO 2471, Paper and board — Determination of opacity (paper backing) — Diffuse reflectance method
© ISO 2009 – All rights reserved 1
---------------------- Page: 6 ----------------------
ISO 9416:2009(E)
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
reflectance factor
R
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
irradiation
NOTE The ratio is often expressed as a percentage.
3.2
luminance factor (C)
R
y
reflectance factor defined with reference to the visual efficiency function V()λ and the CIE illuminant C
NOTE 1 The visual efficiency function describes the sensitivity of the eye to light, so that the luminance factor
corresponds to the attribute of visual perception of the reflecting surface.
NOTE 2 For computational purposes, the V()λ function is identical to the CIE 1931 colour matching function y()λ.
NOTE 3 The luminance factor (C) is also known as the Y(C/2°)-value. In the previous edition of this International
Standard, it was referred to as the luminous reflectance factor.
3.3
single-sheet luminance factor (C)
R
0
luminance factor (C) of a single sheet of paper with a black cavity as backing
3.4
intrinsic luminance factor (C)
R
∞
luminance factor (C) 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 reflectance factor
3.5
opacity (paper backing)
ratio of the single-sheet luminance factor (C), R , to the intrinsic luminance factor (C), R , of the same sample
0 ∞
NOTE The opacity is expressed as a percentage.
3.6
light-absorption coefficient
k
fraction of the spectral radiant flux diffusely incident on a differential layer within a material that is absorbed
when the flux passes through the layer, divided by the thickness of the layer
NOTE The flux referred to is a radiant flux across the differential layer.
2 © ISO 2009 – All rights reserved
---------------------- Page: 7 ----------------------
ISO 9416:2009(E)
3.7
light-scattering coefficient
s
fraction of the spectral radiant flux diffusely incident on a differential layer within a material that is reflected
when the flux passes through the layer, divided by the thickness of the layer
NOTE 1 The flux referred to is a radiant flux across the differential layer.
NOTE 2 It is assumed that no reflection occurs at the boundaries of the materi
...
SLOVENSKI STANDARD
SIST ISO 9416:2011
01-maj-2011
3DSLU'RORþDQMHNRHILFLHQWDVLSDQMDLQNRHILFLHQWDDEVRUSFLMHVYHWOREH XSRUDED
WHRULMHSR.XEHOND0XQNX
Paper -- Determination of light scattering and absorption coefficients (using Kubelka-
Munk theory)
Papier -- Détermination des coefficients de diffusion et d'absorption de la lumière
(utilisation de la théorie de Kubelka-Munk)
Ta slovenski standard je istoveten z: ISO 9416:2009
ICS:
85.060 Papir, karton in lepenka Paper and board
SIST ISO 9416:2011 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
---------------------- Page: 1 ----------------------
SIST ISO 9416:2011
---------------------- Page: 2 ----------------------
SIST ISO 9416:2011
INTERNATIONAL ISO
STANDARD 9416
Second edition
2009-05-01
Paper — Determination of light scattering
and absorption coefficients (using
Kubelka-Munk theory)
Papier — Détermination des coefficients de diffusion et d'absorption de
la lumière (utilisation de la théorie de Kubelka-Munk)
Reference number
ISO 9416:2009(E)
©
ISO 2009
---------------------- Page: 3 ----------------------
SIST ISO 9416:2011
ISO 9416:2009(E)
PDF disclaimer
This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but
shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In
downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat
accepts no liability in this area.
Adobe is a trademark of Adobe Systems Incorporated.
Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation
parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In
the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below.
COPYRIGHT PROTECTED DOCUMENT
© ISO 2009
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,
electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or
ISO's member body in the country of the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2009 – All rights reserved
---------------------- Page: 4 ----------------------
SIST ISO 9416:2011
ISO 9416:2009(E)
Contents Page
Foreword. iv
Introduction . v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions. 2
4 Principle. 3
5 Apparatus . 3
6 Sampling and conditioning. 4
7 Preparation of test pieces. 4
8 Procedure . 4
9 Calculation of results . 5
10 Precision. 5
11 Test report . 6
Annex A (informative) Spectral characteristics of reflectometers for measuring luminance factor. 7
Bibliography . 9
© ISO 2009 – All rights reserved iii
---------------------- Page: 5 ----------------------
SIST ISO 9416:2011
ISO 9416:2009(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.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
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.
ISO 9416 was prepared by Technical Committee ISO/TC 6, Paper, board and pulps.
This second edition cancels and replaces the first edition (ISO 9416:1998), of which it constitutes a technical
revision.
iv © ISO 2009 – All rights reserved
---------------------- Page: 6 ----------------------
SIST ISO 9416:2011
ISO 9416:2009(E)
Introduction
The opacity of a paper is dependent on its grammage, but it is also intrinsically dependent on the light-
absorption and light-scattering coefficients of the material. These coefficients are calculated from the values of
the reflectance factor over a black backing, the intrinsic reflectance factor and the grammage of the sheet.
The calculation of these coefficients requires luminance factor data obtained by measurement under specified
conditions. Apart from the optical properties of the sample, the luminance factor depends on the conditions of
measurement and particularly on the spectral and geometric characteristics of the instrument used for its
determination. This International Standard should therefore be read in conjunction with ISO 2469 and
ISO 2471.
NOTE This method is based on a theory developed by Kubelka and Munk. This theory describes scattering and
absorption processes with certain approximations and simplifications and can therefore yield questionable results in
extreme cases. However, the Kubelka-Munk theory offers a simple method for determining these coefficients with the
instrument used for the determination of optical properties of paper and pulps. Moreover, the method based on this theory
has been successfully used in practical applications.
© ISO 2009 – All rights reserved v
---------------------- Page: 7 ----------------------
SIST ISO 9416:2011
---------------------- Page: 8 ----------------------
SIST ISO 9416:2011
INTERNATIONAL STANDARD ISO 9416:2009(E)
Paper — Determination of light scattering and absorption
coefficients (using Kubelka-Munk theory)
1 Scope
This International Standard specifies a method for the calculation of light-scattering and light-absorption
coefficients based upon diffuse reflectance measurements made under the conditions specified in ISO 2469
using the colour matching function y(λ) and CIE illuminant C.
It is emphasized that the strict evaluation of the light-scattering and light-absorption coefficients requires
conditions which cannot be achieved with the instrumentation specified here. The values obtained by
application of this International Standard are dependent on the application of the Kubelka-Munk equations, not
to full reflectance data but to reflectance factor data obtained using the specified d/0° geometry and a gloss
trap.
The use of the method is restricted to white and near-white uncoated papers with an opacity less than about
95 %. Paper that has been treated with a fluorescent dyestuff or that exhibits significant fluorescence can only
be dealt with if a filter with a cut-off wavelength of 420 nm is used to eliminate all the fluorescence effect in the
UVex(420) mode.
NOTE 1 The residual UV-level in the instrument may depend on whether the instrument is adjusted to UV(C) or
UV(D65) conditions prior to switching to the UVex(420) mode, but it is considered that this uncertainty in the residual level
can be ignored in the application of this International Standard.
NOTE 2 Although this method is restricted to paper, it can be applied to pulp sheets, although this is not in accordance
with this International Standard. In general, when pulps are tested, the light-absorption coefficient at 457 nm
corresponding to the ISO brightness value or the spectral absorption coefficients are of greater interest than the weighted
value standardized in this International Standard.
2 Normative references
The following referenced documents are indispensable for the application 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 536, Paper and board — Determination of grammage
ISO 2469, Paper, board and pulps — Measurement of diffuse radiance factor
ISO 2471, Paper and board — Determination of opacity (paper backing) — Diffuse reflectance method
© ISO 2009 – All rights reserved 1
---------------------- Page: 9 ----------------------
SIST ISO 9416:2011
ISO 9416:2009(E)
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
reflectance factor
R
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
irradiation
NOTE The ratio is often expressed as a percentage.
3.2
luminance factor (C)
R
y
reflectance factor defined with reference to the visual efficiency function V()λ and the CIE illuminant C
NOTE 1 The visual efficiency function describes the sensitivity of the eye to light, so that the luminance factor
corresponds to the attribute of visual perception of the reflecting surface.
NOTE 2 For computational purposes, the V()λ function is identical to the CIE 1931 colour matching function y()λ.
NOTE 3 The luminance factor (C) is also known as the Y(C/2°)-value. In the previous edition of this International
Standard, it was referred to as the luminous reflectance factor.
3.3
single-sheet luminance factor (C)
R
0
luminance factor (C) of a single sheet of paper with a black cavity as backing
3.4
intrinsic luminance factor (C)
R
∞
luminance factor (C) 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 reflectance factor
3.5
opacity (paper backing)
ratio of the single-sheet luminance factor (C), R , to the intrinsic luminance factor (C), R , of the same sample
0 ∞
NOTE The opacity is expressed as a percentage.
3.6
light-absorption coefficient
k
fraction of the spectral radiant flux diffusely incident on a differential layer within a material that is absorbed
when the flux passes through the layer, divided by the thickness of the layer
NOTE The flux referred to is a radiant flux across the differential layer.
2 © IS
...
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Papier -- Détermination des coefficients de diffusion et d'absorption de la lumière (utilisation de la théorie de Kubelka-Munk)Paper -- Determination of light scattering and absorption coefficients (using Kubelka-Munk theory)85.060Papir, karton in lepenkaPaper and boardICS:Ta slovenski standard je istoveten z:ISO 9416:2009oSIST ISO 9416:2011en01-marec-2011oSIST ISO 9416:2011SLOVENSKI
STANDARD
oSIST ISO 9416:2011
Reference numberISO 9416:2009(E)© ISO 2009
INTERNATIONAL STANDARD ISO9416Second edition2009-05-01Paper —Determination of light scattering and absorption coefficients (using Kubelka-Munk theory) Papier — Détermination des coefficients de diffusion et d'absorption de la lumière (utilisation de la théorie de Kubelka-Munk)
oSIST ISO 9416:2011
ISO 9416:2009(E) PDF disclaimer This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat accepts no liability in this area. Adobe is a trademark of Adobe Systems Incorporated. Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below.
COPYRIGHT PROTECTED DOCUMENT
©
ISO 2009 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or ISO's member body in the country of the requester. ISO copyright office Case postale 56 • CH-1211 Geneva 20 Tel.
+ 41 22 749 01 11 Fax
+ 41 22 749 09 47 E-mail
copyright@iso.org Web
www.iso.org Published in Switzerland
ii © ISO 2009 – All rights reserved
oSIST ISO 9416:2011
ISO 9416:2009(E) © ISO 2009 – All rights reserved iiiContents Page Foreword.iv Introduction.v 1 Scope.1 2 Normative references.1 3 Terms and definitions.2 4 Principle.3 5 Apparatus.3 6 Sampling and conditioning.4 7 Preparation of test pieces.4 8 Procedure.4 9 Calculation of results.5 10 Precision.5 11 Test report.6 Annex A (informative)
Spectral characteristics of reflectometers for measuring luminance factor.7 Bibliography.9
oSIST ISO 9416:2011
ISO 9416:2009(E) iv © ISO 2009 – All rights reserved Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. 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. ISO 9416 was prepared by Technical Committee ISO/TC 6, Paper, board and pulps. This second edition cancels and replaces the first edition (ISO 9416:1998), of which it constitutes a technical revision. oSIST ISO 9416:2011
ISO 9416:2009(E) © ISO 2009 – All rights reserved vIntroduction The opacity of a paper is dependent on its grammage, but it is also intrinsically dependent on the light-absorption and light-scattering coefficients of the material. These coefficients are calculated from the values of the reflectance factor over a black backing, the intrinsic reflectance factor and the grammage of the sheet. The calculation of these coefficients requires luminance factor data obtained by measurement under specified conditions. Apart from the optical properties of the sample, the luminance factor depends on the conditions of measurement and particularly on the spectral and geometric characteristics of the instrument used for its determination. This International Standard should therefore be read in conjunction with ISO 2469 and ISO 2471. NOTE This method is based on a theory developed by Kubelka and Munk. This theory describes scattering and absorption processes with certain approximations and simplifications and can therefore yield questionable results in extreme cases. However, the Kubelka-Munk theory offers a simple method for determining these coefficients with the instrument used for the determination of optical properties of paper and pulps. Moreover, the method based on this theory has been successfully used in practical applications.
oSIST ISO 9416:2011
oSIST ISO 9416:2011
INTERNATIONAL STANDARD ISO 9416:2009(E) © ISO 2009 – All rights reserved 1Paper — Determination of light scattering and absorption coefficients (using Kubelka-Munk theory) 1 Scope This International Standard specifies a method for the calculation of light-scattering and light-absorption coefficients based upon diffuse reflectance measurements made under the conditions specified in ISO 2469 using the colour matching function y(λ) and CIE illuminant C. It is emphasized that the strict evaluation of the light-scattering and light-absorption coefficients requires conditions which cannot be achieved with the instrumentation specified here. The values obtained by application of this International Standard are dependent on the application of the Kubelka-Munk equations, not to full reflectance data but to reflectance factor data obtained using the specified d/0° geometry and a gloss trap. The use of the method is restricted to white and near-white uncoated papers with an opacity less than about 95 %. Paper that has been treated with a fluorescent dyestuff or that exhibits significant fluorescence can only be dealt with if a filter with a cut-off wavelength of 420 nm is used to eliminate all the fluorescence effect in the UVex(420) mode. NOTE 1 The residual UV-level in the instrument may depend on whether the instrument is adjusted to UV(C) or UV(D65) conditions prior to switching to the UVex(420) mode, but it is considered that this uncertainty in the residual level can be ignored in the application of this International Standard. NOTE 2 Although this method is restricted to paper, it can be applied to pulp sheets, although this is not in accordance with this International Standard. In general, when pulps are tested, the light-absorption coefficient at 457 nm corresponding to the ISO brightness value or the spectral absorption coefficients are of greater interest than the weighted value standardized in this International Standard. 2 Normative references The following referenced documents are indispensable for the application 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 536, Paper and board — Determination of grammage ISO 2469, Paper, board and pulps — Measurement of diffuse radiance factor ISO 2471, Paper and board — Determination of opacity (paper backing) — Diffuse reflectance method oSIST ISO 9416:2011
ISO 9416:2009(E) 2 © ISO 2009 – All rights reserved 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 reflectance factor R 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 irradiation NOTE The ratio is often expressed as a percentage. 3.2 luminance factor (C) Ry reflectance factor defined with reference to the visual efficiency function ()Vλ and the CIE illuminant C NOTE 1 The visual efficiency function describes the sensitivity of the eye to light, so that the luminance factor corresponds to the attribute of visual perception of the reflecting surface. NOTE 2 For computational purposes, the ()Vλ function is identical to the CIE 1931 colour matching function ().yλ NOTE 3 The luminance factor (C) is also known as the Y(C/2°)-value. In the previous edition of this International Standard, it was referred to as the luminous reflectance factor. 3.3 single-sheet luminance factor (C) R0 luminance factor (C) of a single sheet of paper with a black cavity as backing 3.4 intrinsic luminance factor (C) R∞ luminance factor (C) 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 reflectance factor 3.5 opacity (paper backing) ratio of the single-sheet luminance factor (C), R0, to the intrinsic luminance factor (C), R∞, of the same sample NOTE The opacity is expressed as a percentage. 3.6 light-absorption coefficient k fraction of the spectral radiant flux diffusely incident on a differential layer within a material that is absorbed when the flux passes through the layer, divided by the thickness of the layer NOTE The flux referred to is a radiant flux across the differential layer. o
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