1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS ISO 18936:2012Imaging materials Processedcolour photographs Methods for measuringthermal stabilityBS ISO 18936:2012 BRITISH STANDARDNational forewordThis British Standard is t
2、he UK implementation of ISO 18936:2012.The UK participation in its preparation was entrusted to TechnicalCommittee CPW/42, Photography.A list of organizations represented on this committee can beobtained on request to its secretary.This publication does not purport to include all the necessaryprovis
3、ions of a contract. Users are responsible for its correctapplication. The British Standards Institution 2012. Published by BSI StandardsLimited 2012ISBN 978 0 580 67744 1ICS 37.040.20Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published u
4、nder the authority of theStandards Policy and Strategy Committee on 31 May 2012.Amendments issued since publicationDate Text affectedBS ISO 18936:2012 ISO 2012Imaging materials Processed colour photographs Methods for measuring thermal stabilityMatriaux pour limage Photographies couleurs aprs traite
5、ment Mthodes de mesure de la stabilit thermiqueINTERNATIONAL STANDARDISO18936First edition2012-04-15Reference numberISO 18936:2012(E)BS ISO 18936:2012ISO 18936:2012(E)ii ISO 2012 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2012All rights reserved. Unless otherwise specified, no part of this
6、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 ISOs member body in the country of the requester.ISO copyright officeCase postale 56 CH-1211 Ge
7、neva 20Tel. + 41 22 749 01 11Fax + 41 22 749 09 47E-mail copyrightiso.orgWeb www.iso.orgPublished in SwitzerlandBS ISO 18936:2012ISO 18936:2012(E) ISO 2012 All rights reserved iiiContents PageForeword ivIntroduction v1 Scope 12 Normative references . 13 Terms and definitions . 14 Requirements . 25 S
8、ample preparation . 35.1 Target selection 35.2 Use of replicates and reference samples . 36 Measurement conditions . 37 Measured attributes 47.1 Definition of density attributes 47.2 Density attributes to be measured . 47.3 Definitions of colourimetry terms . 57.4 Colourimetry values to be measured
9、. 58 Calculations and computations . 58.1 Computation of densitometric attributes 58.2 Density change in dminpatches . 58.3 Percent density change in pure primary colour patches . 58.4 Percent density change in secondary (mixed) colour patches 58.5 Percent density change in a composite neutral patch
10、 58.6 Colour balance shift in a composite neutral patch 68.7 Colour balance in secondary (mixed) colour patches 68.8 Colour balance in dminpatches by densitometry . 68.9 Colour balance in dminpatches by colourimetry 69 Test methods Thermal stability 69.1 General . 69.2 Test methods and equipment . 8
11、9.3 Computation of dark stability .1010 Test report .1010.1 General reporting requirements 1010.2 Test reporting .10Annex A (informative) A method for interpolation .12Annex B (informative) Illustration of Arrhenius calculation for dark stability .13Bibliography .16BS ISO 18936:2012ISO 18936:2012(E)
12、ForewordISO (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 te
13、chnical 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
14、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 t
15、o 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
16、identifying any or all such patent rights.ISO 18936 was prepared by Technical Committee ISO/TC 42, Photography.iv ISO 2012 All rights reservedBS ISO 18936:2012ISO 18936:2012(E)IntroductionThis International Standard covers the methods and procedures for measuring the long-term, dark storage stabilit
17、y (thermal stability) of colour photographs.Today, the majority of photographs are made with colour dyes and pigments. The length of time that such photographs are to be kept can vary from a few days to many hundreds of years, and the importance of image stability can be correspondingly small or gre
18、at. Often the ultimate use of a particular photograph may not be known at the outset. Knowledge of the useful life of colour photographs is important to many users, especially since stability requirements often vary depending upon the application. For museums, archives and others responsible for the
19、 care of colour photographic materials, an understanding of the behaviour of these materials under various storage and display conditions is essential if they are to be preserved in good condition for long periods of time.Any change in density, contrast or stain, whether due to colourant fading, cha
20、nges in colourant morphology or discolouration of residual substances will change the appearance of the photograph.The most damaging change tends to be contrast balance distortions brought about by differential fading of the three image colourants. These manifest themselves as shifts in colour balan
21、ce from highlights to shadows that are especially noticeable in a scale of neutrals, for example a shift from magenta to green due to fading of the photographs magenta image colourant, or from yellow to blue or cyan to red due to fading of the yellow or cyan colourant.The second most consequential c
22、hange is that caused by an increase in stain. The result may simply be a discolouration of the Dminareas or a change in the Dmincolour balance.Cyan, magenta, yellow and sometimes black, red, green and blue colourants that are dispersed in transparent binder layers, or absorbed onto special receiver
23、layers coated onto transparent or white opaque supports, form the images of most modern colour photographs. Colour photographic images typically fade during storage and display; they will usually also change in colour balance because the image colourants seldom fade at the same rate. In addition, a
24、yellowish (or occasionally other colour) stain may form and physical degradation may occur, such as embrittlement and cracking of the support and image layers. The rate of fading and staining is governed principally by the intrinsic stability of the colour photographic material and by the conditions
25、 under which the photograph is stored and displayed. The quality of chemical processing or post-processing is another important factor. Post-processing treatments and, in the case of digitally generated photographs, post-production treatments, such as application of lacquers, plastic laminates and r
26、etouching colours, also may affect the stability of colour materials.The three main factors that influence storage behaviour, or dark stability, are the temperature and relative humidity of the air that has access to the photograph, as well as atmospheric pollutants to which the photograph is expose
27、d. High temperature, particularly in combination with high relative humidity, will accelerate the chemical reactions that can lead to degradation of one or more of the image colourants. Low-temperature, low-humidity storage, on the other hand, can greatly prolong the life of photographic colour imag
28、es for typical materials. Other potential causes of image degradation are microorganisms and insects.Most modern photographs degrade too slowly under normal room conditions to permit evaluation of their dark storage stability within reasonable periods. However, it is possible to assess the probable,
29、 long-term changes of some photographs under low and moderate keeping conditions with accelerated, high-temperature tests, because recognizable losses in image quality under high temperatures are apt to be generated also under milder temperatures, if at a slower pace. The effects of relative humidit
30、y on thermal degradation can also be evaluated with Arrhenius tests conducted at two or more humidity levels.Long-term changes in image density, colour balance and stain level can be reasonably estimated only when good correlation has been confirmed between accelerated tests and actual conditions of
31、 use.Density changes induced by the test conditions and measured during and after incubations include those in the support and in the various auxiliary layers that may be in a particular product. With most materials, however, the major changes occur in the image-bearing layer. An exception to this i
32、s found in some inkjet papers where the inks are thermally stable and substrate yellowing is the failure mode (see Reference 9). ISO 2012 All rights reserved vBS ISO 18936:2012ISO 18936:2012(E)The tests for predicting the stability of colour photographic images in dark storage are based on an adapta
33、tion of the Arrhenius method described by Bard et al. (see References 2 and 3) and earlier references by Arrhenius, Steiger and others (see References 4, 5 and 6). Although this method is derived from well understood and proven theoretical precepts of chemistry, the validity of its application to pr
34、edicting changes of photographic images rests on empirical confirmation. Although many chromogenic-type colour products yield image fading and staining data in both accelerated and non-accelerated dark ageing tests that are in agreement with the Arrhenius relationship, some other types of products d
35、o not. For example, integral-type instant colour print materials often exhibit atypical staining at elevated temperatures; treatment of some chromogenic materials at temperatures above 80 C and 60 %RH may cause loss of incorporated high-boiling solvents and abnormal image degradation; and the dyes o
36、f silver dye-bleach images deaggregate at combinations of very high temperature and high relative humidity, causing abnormal changes in colour balance and saturation (see Reference 7 in the bibliography). In general, photographic materials tend to undergo dramatic changes at relative humidities abov
37、e 60 % (especially at the high temperatures employed in accelerated tests) owing to changes in the physical properties of gelatine and other binder materials. Lower maximum relative humidities may need to be tested for some of the more humidity-sensitive inkjet materials because of phase changes suc
38、h as melting point or glass transition temperature.vi ISO 2012 All rights reservedBS ISO 18936:2012INTERNATIONAL STANDARD ISO 18936:2012(E)Imaging materials Processed colour photographs Methods for measuring thermal stability1 ScopeThis International Standard describes test methods for determining t
39、he long-term dark storage stability of colour photographic images.It is applicable to colour photographic images made with traditional photographic materials. These images are generated with chromogenic, silver dye-bleach, dye transfer, dye-diffusion-transfer “instant” systems and similar systems. T
40、he test method specified in this International Standard also covers the dark-stability of digital colour images produced with dry- and liquid-toner electrophotography, thermal dye transfer (sometimes called “dye sublimation”), and inkjet printing systems.2 Normative referencesThe following reference
41、d 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 5-3, Photography and graphic technology Density measurements Part 3:
42、Spectral conditionsISO 5-4, Photography and graphic technology Density measurements Part 4: Geometric conditions for reflection densityISO 11664-4, Colorimetry Part 4: CIE 1976 L*a*b* Colour spaceISO 18911, Imaging materials Processed safety photographic films Storage practicesISO 18913, Imaging mat
43、erials Permanence VocabularyISO 18920, Imaging materials Reflection prints Storage practicesISO 18924, Imaging materials Test method for Arrhenius-type predictionsISO 13655, Graphic technology Spectral measurement and colorimetric computation for graphic arts imagesISO 18941, Imaging materials Colou
44、r reflection prints Test method for ozone gas fading stabilityISO 18944, Imaging materials Reflection colour photographic prints Test print construction and measurement1)3 Terms and definitionsFor the purposes of this document, the terms and definitions given in ISO 18913 and the following apply.3.1
45、operational control pointset point for equilibrium conditions measured at sensor location(s) in an exposure deviceASTM G 1131) To be published. ISO 2012 All rights reserved 1BS ISO 18936:2012ISO 18936:2012(E)3.2operational fluctuationspositive and negative deviations from the setting of the sensor a
46、t the operational control set point during equilibrium conditions in a laboratory-accelerated weathering deviceNOTE The operational fluctuations are the result of unavoidable machine variables and do not include measurement uncertainty. The operational fluctuations apply only at the location of the
47、control sensor and do not imply uniformity of conditions throughout the test chamber.ASTM G 1133.3operational uniformityrange around the operational control point for measured parameters within the intended exposure area within the limits of intended operational rangeASTM G 1133.4uncertainty (of mea
48、surement)parameter, associated with the result of a measurement, that characterizes the dispersion of the values that could be reasonably attributed to the measurandNOTE 1 The parameter may be, for example, a standard deviation (or a given multiple of it), or the half-width of an interval having a s
49、tated confidence level. NOTE 2 Uncertainty of measurement comprises, in general, many components. Some of these components may be evaluated from statistical distribution of the results of series of measurements and can be characterized by experimental standard deviations. The other components, which can also be characterized by standard deviations, are evaluated from assumed probability distributions based on experience or other information. NOTE 3 It is understood that the result of the
