1、BS ISO 12641-1:2016Graphic technology Prepressdigital data exchange Colourtargets for input scannercalibrationPart 1: Colour targets for input scannercalibrationBSI Standards PublicationWB11885_BSI_StandardCovs_2013_AW.indd 1 15/05/2013 15:06BS ISO 12641-1:2016 BRITISH STANDARDNational forewordThis
2、British Standard is the UK implementation of ISO 12641-1:2016.The UK participation in its preparation was entrusted to TechnicalCommittee PAI/43, Graphic technology.A list of organizations represented on this committee can beobtained on request to its secretary.This publication does not purport to i
3、nclude all the necessaryprovisions of a contract. Users are responsible for its correctapplication. The British Standards Institution 2016. Published by BSI StandardsLimited 2016ISBN 978 0 580 90183 6ICS 35.240.30; 37.100.99Compliance with a British Standard cannot confer immunity fromlegal obligati
4、ons.This British Standard was published under the authority of theStandards Policy and Strategy Committee on 31 May 2016.Amendments issued since publicationDate Text affectedBS ISO 12641-1:2016 ISO 2016Graphic technology Prepress digital data exchange Colour targets for input scanner calibration Par
5、t 1: Colour targets for input scanner calibrationTechnologie graphique change de donnes numriques de primpression Cibles de couleur pour talonnage lentre du scannerINTERNATIONAL STANDARDISO12641-1First edition2016-05-01Reference numberISO 12641-1:2016(E)BS ISO 12641-1:2016ISO 12641-1:2016(E)ii ISO 2
6、016 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2016, Published in SwitzerlandAll rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on the
7、internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below or ISOs member body in the country of the requester.ISO copyright officeCh. de Blandonnet 8 CP 401CH-1214 Vernier, Geneva, SwitzerlandTel. +41 22 749 01 11Fax +41 22 749 09 47c
8、opyrightiso.orgwww.iso.orgBS ISO 12641-1:2016ISO 12641-1:2016(E)Foreword ivIntroduction v1 Scope . 12 Normative references 13 Terms and definitions . 14 Requirements 44.1 Target design 44.2 Transmission targets . 44.2.1 Target layout and physical characteristics 44.2.2 Patch size 94.2.3 Colour gamut
9、 mapping . 94.2.4 Neutral and dye scale values 104.2.5 Neutral scale mapping .114.3 Reflection targets . 114.3.1 Target layout and physical characteristics .114.3.2 Patch size . 134.3.3 Colour gamut mapping 144.3.4 Neutral and dye scale values 144.3.5 Neutral scale mapping .154.4 Allowable tolerance
10、s on patch values 154.4.1 Uncalibrated targets 154.4.2 Calibrated targets .164.5 Spectral measurement and colorimetric calculation 164.6 Data reporting 164.7 Data file format 164.7.1 File format 164.7.2 Keyword syntax and usage . 164.7.3 Data format identifiers 174.8 Useable target life 19Annex A (i
11、nformative) Gamut mapping Computational reference .20Annex B (informative) Application notes .22Bibliography .25 ISO 2016 All rights reserved iiiContents PageBS ISO 12641-1:2016ISO 12641-1:2016(E)ForewordISO (the International Organization for Standardization) is a worldwide federation of national s
12、tandards 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
13、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
14、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/
15、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
16、 the Introduction and/or on the ISO list of patent declarations received (see www.iso.org/patents).Any trade name used in this document is information given for the convenience of users and does not constitute an endorsement.For an explanation on the meaning of ISO specific terms and expressions rel
17、ated to conformity assessment, as well as information about ISOs adherence to the WTO principles in the Technical Barriers to Trade (TBT) see the following URL: Foreword - Supplementary informationThe committee responsible for this document is ISO/TC 130, Graphic technology.This first edition of ISO
18、 12641-1 cancels and replaces ISO 12641:1997, which has been technically revised to take account of the technical advancements in the related fields and the associated equipment.ISO 12641 consists of the following parts, under the general title Graphic technology Prepress digital data exchange: Part
19、 1: Colour targets for input scanner calibrationAn additional part dealing with advanced colour targets for input scanner calibration is planned.Annexes A and B are for information only.iv ISO 2016 All rights reservedBS ISO 12641-1:2016ISO 12641-1:2016(E)IntroductionThe technical requirements of thi
20、s part of ISO 12641 are identical to the American National Standards IT8.7/1-1993 and IT8.7/2-1993. These Standards resulted from the joint efforts of an international industry group that included participants representing a broad range of prepress vendors, film manufacturers, and users. This group,
21、 initially identified as the digital data exchange standards (DDES) committee, later became the founders of the ANSI IT8 (Image Technology) accredited standards committee which is responsible for electronic data exchange standards in graphic arts prepress.Purpose of this part of ISO 12641Colour inpu
22、t scanners do not all analyse colour the same way the human eye does. These devices are designed to optimize the signal generated when typical materials are scanned. Colour reflection and transparency products use various combinations of proprietary dye sets to achieve visual responses that simulate
23、 the colour appearance of natural scene elements. The ability to achieve the same colour appearance from different combinations of dyes is referred to as metamerism. Because both photographic dyes and input scanner sensitivities vary from product to product, there is variability in the input scanner
24、 response to metameric colours produced by the various materials. The intent of this part of ISO 12641 is to define an input test target that will allow any colour input scanner to be calibrated with any film or paper dye set used to create the target. This part of ISO 12641 is intended to address t
25、he colour reflection and transparency products which are generally used for input to the preparatory process for printing and publishing.The target was designed to be useable for calibration by visual comparison and as a numerical data target for electronic systems and future development. The target
26、 design made use of a uniform colour space to optimize the spacing of target patches. The tolerances developed for individual coloured patches meet the values needed for both numerical and visual analysis.Design of the targetThe CIE 1976 (L*a*b* ) or CIELAB colour space was chosen as the space to be
27、 used for the design of the colour calibration target. Uniform spacing in hue angle, lightness and chroma, and tolerancing in terms of differences in these parameters (E*ab) is believed to provide a reasonable distribution of coloured patches in the most effective manner. Although CIELAB was defined
28、 with reference to reflection viewing conditions, tolerancing in terms of vector differences (E*ab) does provide a reasonable error estimate for transmission materials as well, although the uniformity of the space is dependent upon the conditions of viewing.The design goal was to define a target tha
29、t would have, as its main part, as many common coloured patches as was practical, regardless of the dye set used. The remainder of the target is intended to define the unique colour characteristics of the particular dye set used to create a specific target; the values for each target patch is to be
30、established using a common procedure.To provide a reasonable measure of the colour gamut that is within the capability of modern colour papers and films, all manufacturers of these products were invited to provide colour dye data along with the necessary minimum and maximum density data for each of
31、their image forming colour dye sets. Data were provided by Agfa Company, Eastman Kodak Company, Fuji Photo Film Company, and Konica Corporation. These data were then used to estimate the CIELAB colour gamut that each paper and film dye set could produce. This estimate was achieved by mathematical mo
32、delling (by several of the participating companies) using methods which were different but gave very similar results. Annex A provides additional reference material concerning the method used in selecting aim values.The following documents provide reference information on the computational methods u
33、sed in gamut determination.1. N. Ohta, “The Color Gamut Obtainable by the Combination of Subtractive Color Dyes. V. Optimum Absorption Bands as Defined by Nonlinear Optimization Technique.” Journal of Imaging Science, 30, 9-12 (1986)1. ISO 2016 All rights reserved vBS ISO 12641-1:2016ISO 12641-1:201
34、6(E)2. M. Inui, “Fast Algorithm for Computing Color Gamuts,” Colour Research and Application, 18, 341-348 (1993)4.All computations were based upon the use of the CIE 2 degree observer and D50illuminant. All transmission measurements were made using diffuse/normal or normal/diffuse geometry as define
35、d for total transmittance. All reflection measurements were made using 0/45 or 45/0 geometry as defined in ISO 13655. The reference white was assumed to be a perfect diffuser. The use of an absolute reference allows all colours on similar media (reflection or transmission) that have the same colorim
36、etric definition to also look the same when viewed at the same time.The gamut plots developed were then used to determine the colour gamuts for film and paper that were common to all of the provided dye families. The limiting values of chroma were then reduced to 80 % of their computed values to cre
37、ate a “common gamut” for purposes of target design.The goal was to have all coloured patches defined in the same way (regardless of the product used) and to have as many patches as practical. The defined colour gamut therefore required a pattern with a consistent reference. An existing colour input
38、target provided by Eastman Kodak Company under the designation of “Kodak Colour Reproduction Guides, Q-60” was used as a guide in the development of the target. The Q-60 target used 12 approximately uniformly spaced hue angles in CIELAB. These were sampled at three chroma values at each of three lig
39、htness levels. Although this pattern does not provide equal spacing in terms of E*ab, it does provide an easily understandable and defined patch arrangement. It was adopted for these targets with the addition of a fourth product-specific chroma value at each hue angle/lightness combination.Lightness
40、 levels were chosen for each hue angle to best characterize the gamut at that hue angle. The three common chroma values were then chosen such that one fell on the computed 80 % chroma limit common to all the products and the others were equally spaced in chroma between this value and the neutral. Th
41、e fourth chroma, which is product-specific, was defined to be the maximum available from each product at the specific hue angle and lightness level. This provided a consistent mapping for all products.It was also felt to be important to include scales in each of the individual dyes, dye pairs, and a
42、 dye neutral along with areas to define product minimum and maximum densities.A “vendor-optional” area was provided so that different target manufacturers could add unique patches of their own determination beyond those which are required by this International Standard.Manufacturing tolerancesIn ord
43、er to permit practical production of these targets, tolerances had to be set which were capable of being achieved over a significant number of targets. However, this conflicted with the relatively narrow tolerances required for numerical colour calibration. Different tolerances were therefore define
44、d for differing applications, with the objective of minimizing variations as far as was reasonable.vi ISO 2016 All rights reservedBS ISO 12641-1:2016INTERNATIONAL STANDARD ISO 12641-1:2016(E)Graphic technology Prepress digital data exchange Colour targets for input scanner calibration Part 1: Colour
45、 targets for input scanner calibration1 ScopeThis part of ISO 12641 defines the layout and colorimetric values of targets for use in the calibration of a photographic product/input scanner combination (as used in the preparatory process for printing and publishing). One target is defined for positiv
46、e colour transparency film and another is defined for colour photographic paper.2 Normative referencesThe following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated
47、 references, the latest edition of the referenced document (including any amendments) applies.ISO 1008, Photography Paper dimensions Pictorial sheetsISO 1012, Photography Films in sheets and rolls for general use DimensionsISO 13655, Graphic technology Spectral measurement and colorimetric computati
48、on for graphic arts images3 Terms and definitionsFor the purposes of this document, the following terms and definitions apply.3.1CIE tristimulus valueamount of the three reference colour stimuli, in the CIE-specified trichromatic system, required to match the colour of the stimulus consideredNote 1
49、to entry: In the 1931 CIE standard colorimetric system, the tristimulus values are represented by the symbols X, Y, Z.3.2CIELAB colour differenceCIE 1976 L*, a*, b* colour differenceE*abdifference between two colour stimuli defined as the Euclidean distance between the points representing them in L*, a*, b* space=()+()+()ELab*ab22212whereL*, a*, and b* is the difference between corresponding values for the two stimuli. ISO 2016 All rights reserved 1BS ISO 12641-1:2016ISO 12641-1:2016(E)SOU
