1、BSI Standards PublicationBS ISO 12646:2015Graphic technology Displays for colour proofing CharacteristicsBS ISO 12646:2015 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of ISO 12646:2015. Itsupersedes BS ISO 12646:2008+A1:2010 which is withdrawn.The UK participation
2、 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 include all the necessaryprovisions of a contract. Users are responsible for its co
3、rrectapplication. The British Standards Institution 2015. Published by BSI StandardsLimited 2015ISBN 978 0 580 75285 8ICS 37.100.01Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the authority of theStandards Policy and Strate
4、gy Committee on 31 July 2015.Amendments issued since publicationDate Text affectedBS ISO 12646:2015 ISO 2015Graphic technology Displays for colour proofing CharacteristicsTechnologie graphique Affichages pour la ralisation dpreuves en couleur CaractristiquesINTERNATIONAL STANDARDISO12646Third editio
5、n2015-07-15Reference numberISO 12646:2015(E)BS ISO 12646:2015ISO 12646:2015(E)ii ISO 2015 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2015, Published in SwitzerlandAll rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form
6、 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 ISOs member body in the country of the requester.ISO copyright officeCh. de Blandonnet
7、8 CP 401CH-1214 Vernier, Geneva, SwitzerlandTel. +41 22 749 01 11Fax +41 22 749 09 47copyrightiso.orgwww.iso.orgBS ISO 12646:2015ISO 12646:2015(E)Foreword ivIntroduction v1 Scope . 12 Normative references 13 Terms and definitions . 14 Requirements 24.1 General . 24.2 Uniformity of luminance and chro
8、maticity 34.2.1 General 34.2.2 Evaluation of tone uniformity . 34.2.3 Tonality evaluation (uniformity) . 34.3 Viewing cone characteristics 34.4 Reflective characteristics . 45 Test methods . 55.1 General . 55.2 Preparation and display set-up . 55.3 Viewing angle dependent tonality evaluation (“Gamma
9、”) 55.4 Measurement conditions 65.4.1 Photometric and colorimetric measurements . 65.4.2 Measurements as a function of viewing direction 8Bibliography .11 ISO 2015 All rights reserved iiiContents PageBS ISO 12646:2015ISO 12646:2015(E)ForewordISO (the International Organization for Standardization) i
10、s 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 represe
11、nted 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
12、 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/IE
13、C 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
14、development of the document will be in the Introduction and/or on the ISO list of patent declarations received (see www.iso.org/patents).Any trade name used in this document is information given for the convenience of users and does not constitute an endorsement.For an explanation on the meaning of
15、ISO specific terms and expressions related 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, Graphi
16、c technology.This third edition cancels and replaces the second edition (ISO 12646:2008), which has been technically revised to improve the compatibility with the requirements of soft proofing defined in ISO 14861.iv ISO 2015 All rights reservedBS ISO 12646:2015ISO 12646:2015(E)IntroductionThe abili
17、ty to match colour images displayed on colour displays to the images produced when the same digital file is rendered by proofing and printing systems (commonly referred to as “soft” proofing) is increasingly expected in graphic arts. Obtaining such a match is not simple and to be fully accurate requ
18、ires careful control of many aspects of the process. The primary purpose of this International Standard is to make recommendations with respect to the soft proof displays requirements. If these are met, it is then possible for a soft proofing system such as defined in ISO 14861 to accurately colour
19、match to the hard copy proof. Hence, this International Standard is intended for display manufacturers in order to qualify their display for use in graphic arts proofing systems.The appearance of a colour image on a colour display is influenced by many physical factors other than controlled ambient
20、viewing conditions. Among the most important of these are uniformity, size and resolution (in order to permit rendition of the proof at close to its normal size and with the finest detail visible on the hard copy at normal viewing distances), variation of electro-optical properties with viewing dire
21、ction, freedom from flicker and glare (specular reflections with distinct images), the opto-electronic calibration of the display, and the settings of its display driver software. In this regard, to be acceptable in a proofing system that provides a reasonable level of image quality, the display nee
22、ds to also exhibit these properties at an acceptable quality.Note that even for displays of the highest quality, the appearance of the displayed image will be limited by the accuracy of the colour transformation used for converting the digital file from its encoded colour space to that required for
23、display purposes.This International Standard specifies requirements for displays to be used in soft proofing systems defined by ISO 14861. ISO 14861 primarily focuses on applications where the displayed image will be compared to a hard copy in an adjacent viewing cabinet or where the viewing cabinet
24、 intentionally contains the display. Furthermore, in order to address the different needs for the soft proofing use cases, two different conformance levels (class A and class B) will be defined in this International Standard.However, in some practical situations, the image on the screen is evaluated
25、 in the absence of a hard copy. This International Standard might be used as reference, but this is not required. Users of this International Standard will also benefit from CIE Publication 122 which provides an overview of the relationship between digital and colorimetric data. Those unfamiliar wit
26、h the evaluation of displays will also find it helpful to read IEC 61223-2-5 which contains much useful detailed information about evaluation and testing of image display devices. ISO 2015 All rights reserved vBS ISO 12646:2015BS ISO 12646:2015Graphic technology Displays for colour proofing Characte
27、ristics1 ScopeThis International Standard specifies requirements for two conformance levels for the characteristics of displays to be used for soft proofing of colour images. Included are requirements for uniformity and variations of electro-optical properties with viewing direction for different dr
28、iving signals.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 references, the latest edition of the referenced document (includ
29、ing any amendments) applies.ISO 13655, Graphic technology Spectral measurement and colorimetric computation for graphic arts images3 Terms and definitionsFor the purposes of this document, the following terms and definitions apply.3.1calibrationset of operations that establish, under specified condi
30、tions, the relationship between values of quantities indicated by a measuring instrument or measuring system or values represented by a material measure of a reference material and the corresponding values realized by standardsSOURCE: ISO International Vocabulary of Basic and General Terms in Metrol
31、ogyNote 1 to entry: However, in typical graphic arts, use cases calibration is understood as an active process where a display or a printer is adjusted such that it produces the defined aim values.3.2colorimeterinstrument for measuring colour values such as the tristimulus values of a colour stimulu
32、sSOURCE: ISO 12637-2:2008, 2.183.3design viewing directionDVDdirection for which specific electro-optical characteristics of the display have been optimizedNote 1 to entry: Examples of important electro-optical characteristics are maximum luminance and maximum contrast in definite direction.3.4gamma
33、best-fit parameter which relates the display normalized output luminance to a normalized input digital value presented to the display system including its hardware and software components as given in Formula (1):LS O=()+INTERNATIONAL STANDARD ISO 12646:2015(E) ISO 2015 All rights reserved 1BS ISO 12
34、646:2015ISO 12646:2015(E)whereL is the normalized output luminance;S is the normalized input digital value;O is the offset.3.5ON-statecondition in which the display is switched onNote 1 to entry: This definition is important for light-valve-like displays which might emit a significant light intensit
35、y even when displaying the darkest image (R = G = B = 0) in the ON-state.3.6spectrophotometerinstrument for measuring the reflectance or transmittance of light (or other radiation) by an object at one or more wavelengths in the spectrumSOURCE: ISO 105-A08:2001, 2.243.7viewing coneVCconical space ori
36、ginating at the display surface that includes all viewing directions with a specified angle of inclination, (3.8)3.8viewing angleangle between the normal to the display and the design viewing direction (3.3)4 Requirements4.1 GeneralAll display tests should be performed for a display calibrated to a
37、luminance of 160 cd/m2and a chromaticity corresponding to a D50 (x = 0,3 457 and y = 0,3 585) illuminant with a 2 observer at a gamma of 2,2. The display shall display a ”white” image consisting of the maximum value in each channel, red, green, and blue (255 for 8-bit). It shall be reported if other
38、 calibration aims were used.NOTE 1 This calibration condition is typical of the conditions used in the graphic arts industry and ensures that the results of different tested displays can be compared because uniformity can be dependent to some extent on the chosen gamma, luminance, and white point se
39、ttings.If a display to be tested will be used solely in a specific soft proofing system where no display calibration is used, but only the state of the display is characterized, the calibration can be omitted. The luminance, the white point chromaticity (as expressed in CIExy units), and tone reprod
40、uction curve (as expressed by a single gamma value or as a set of tabulated values) shall be reported.The display shall be tested in a stable condition. In order to establish the individual stabilization time, each display to be tested shall be operated in the calibration mode for 12 h in a room wit
41、h controlled temperature conditions. The room temperature shall not change more than 0,5 C and shall be in the range of 18 C to 28 C.The stabilization time (warm up time) is achieved when the luminance change is less than 2 % (compared to the average of the measurements of the last 9 h of the 12 h p
42、eriod) and the white point is within 0,005 for CIE x, y of the calibrated conditions. If the display will not achieve stable conditions, it shall not be used.2 ISO 2015 All rights reservedBS ISO 12646:2015ISO 12646:2015(E)The warm up behaviour of a display shall be reported with a graph of luminance
43、 and CIE x, y in measured values and in percentage compared to the average of the last 9 h of the 12 h period.NOTE 2 When using viewing condition P2, according to ISO 3664, a luminance of 160 cd/m2correlates with an illuminance of 500 lux illuminating a perfect reflecting diffusor.4.2 Uniformity of
44、luminance and chromaticity4.2.1 GeneralThe uniformity of a soft proofing system is vital and shall be checked for solid colours and for tonality (gradation) changes of the screen. If the informative requirements of 4.2.2. or 4.2.3 are not met, this shall be reported. Therefore, the following method
45、is normatively required in ISO 14861. However, since there are soft proofing solutions that are able to perform a spatial resolved uniformity correction, this International Standard makes the uniformity assessment informative.It shall be reported and if hardware based, look up table display correcti
46、ons are turned on (if present).4.2.2 Evaluation of tone uniformityThe CIELAB values of a uniform 5 5 grid are calculated using the measurement of the centre patch at maximum driving as the reference white illuminant. Note that this method may result in some CIEL* values being greater than 100. 24 re
47、adings are compared with the centre colour for three different driving levels, namely white, at the maximum driving level (R = G = B = 255 for 8-bit displays), grey at about half maximum driving level (R = G = B = 127 for 8-bit displays), and dark grey at about one fourth of maximum driving level (R
48、 = G = B = 63 for 8-bit displays) by means of the DE00 colour difference formulae. For the white and the grey driving levels, the DE00 colour differences should be equal or less than four.4.2.3 Tonality evaluation (uniformity)Utilizing luminance (cd/m2) measurements of grey at half maximum driving l
49、evel (R = G = B = 127 for 8-bit displays) and white at max driving level (R = G = B = 255 for 8-bit displays) the grey/white ratio should be calculated for the 25 regions. For the non-central regions, new ratios, Ti, with i = 1,24 should be computed by dividing the individual grey/white ratios, Ri, with i = 1,.,24 by the grey/white ratio of the centre, Rc, subtracting one and calculate the absolute value of the number. This measure of the deviation from uniform tonality should be less than 10 %, i.e. max (Ti), i = 1
