1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS ISO 18929:2012Imaging materials Wet-processed silver-gelatintype black-and-whitephotographic reflection prints Specifications for darkstorageBS ISO 18929:2012 BRITISH STANDARD
2、National forewordThis British Standard is the UK implementation of ISO 18929:2012. Itsupersedes BS ISO 18929:2003 which is withdrawn.The UK participation in its preparation was entrusted to TechnicalCommittee CPW/42, Photography.A list of organizations represented on this committee can beobtained on
3、 request to its secretary.This publication does not purport to include all the necessaryprovisions of a contract. Users are responsible for its correctapplication. The British Standards Institution 2012. Published by BSI StandardsLimited 2012ISBN 978 0 580 75883 6ICS 37.040.20Compliance with a Briti
4、sh Standard cannot confer immunity fromlegal obligations.This British Standard was published under the authority of theStandards Policy and Strategy Committee on 30 April 2012.Amendments issued since publicationDate Text affectedBS ISO 18929:2012 ISO 2012Imaging materials Wet-processed silver-gelati
5、n type black-and-white photographic reflection prints Specifications for dark storageMatriaux pour limage Tirages photographiques par rflexion par traitement humide glatinoargentique de type noir et blanc Spcifications pour le stockage dans lobscuritINTERNATIONAL STANDARDISO18929Second edition2012-0
6、4-01Reference numberISO 18929:2012(E)BS ISO 18929:2012ISO 18929:2012(E)ii ISO 2012 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2012All 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,
7、 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 Geneva 20Tel. + 41 22 749 01 11Fax + 41 22 749 09 47E-mail copyrightiso.orgWeb www.iso.orgPublishe
8、d in SwitzerlandBS ISO 18929:2012ISO 18929:2012(E) ISO 2012 All rights reserved iiiContents PageForeword ivIntroduction v1 Scope 12 Normative references . 13 Terms and definitions . 14 Safety and operational precautions . 24.1 Hazard warnings 24.2 Hazard information code system 24.3 Safety precautio
9、ns 35 Requirements for physical stability of prints 35.1 Wedge brittleness 35.2 Tensile energy absorption (see Annex C) . 35.3 Resin cracking of RC papers (see Annex D) 36 Requirements for processed image stability (see Annex E) . 36.1 Residual thiosulfate concentration 36.2 Residual silver concentr
10、ation 46.3 Yellowing limit (see Annex G) 47 LE designation . 48 Test methods 48.1 Wedge brittleness 48.2 Tensile energy absorption 58.3 Yellowing . 68.4 Residual silver compound test using cyanogen iodide (CNI) extraction . 68.5 Residual silver compound test by use of sulfuric acid/nitric acid extra
11、ction 78.6 Resin cracking . 8Annex A (informative) Stabilization treatments to prevent silver oxidation . 11Annex B (informative) Potential silver-image discolouration of RC prints under display conditions 12Annex C (informative) Tensile energy absorption .13Annex D (informative) Environmental resin
12、-cracking .14Annex E (informative) Effects of residual thiosulfate and silver in processed prints .15Annex F (informative) Degradation of silver images due to extraneous oxidation 17Annex G (informative) Discolouration of black-and-white photographic prints 18Annex H (informative) Densitometric vers
13、us spectrophotometric measurement of yellowing 20Bibliography .21BS ISO 18929:2012ISO 18929:2012(E)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 ca
14、rried 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
15、. 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 Internat
16、ional 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 el
17、ements 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 18929 was prepared by Technical Committee ISO/TC 42, Photography.This second edition cancels and replaces the first edition (ISO 18929:2003), which has bee
18、n technically revised.iv ISO 2012 All rights reservedBS ISO 18929:2012ISO 18929:2012(E)IntroductionBlack-and-white silver-gelatin fibre-base papers have been important imaging materials for well over 100 years. Reflection prints, made with such papers, have become increasingly important pictorial an
19、d documentary records that are housed in many libraries, archives, museums, universities and other public and private institutions. Although the intrinsic stability of properly processed and stored silver-gelatin prints is very good, there are internal and external factors that can cause degradation
20、 of such prints during storage and shorten their useful life. This International Standard provides specifications for tests that evaluate the stability of black-and-white silver-gelatin prints under prescribed storage conditions. It does not cover tests for the possible harmful effects of extended e
21、xposure to light.Black-and-white prints are laminates, whose main components are a paper base, a white opaque intermediate layer, an image layer, and a protective layer. Paper has been used as a support for prints since about 1840. The history of its evolution into a very stable, high alpha-cellulos
22、e type fibre-base in the 1920s and to a polyethylene resin-coated (RC) paper base in the 1960s has been covered extensively in the literature (see References 11, 12, 13, 14 and 15).The intermediate, white opaque layer can be of two types. For fibre paper, since the 1880s it has been a gelatin layer
23、containing white barium sulfate pigment (baryta layer) and other additives that enhance the papers reflectivity, hardness, holdout, adhesion and surface characteristics (glossy, matte, textured). The second type came into use in the 1960s with the introduction of an RC base. This has a paper core co
24、ated on both sides with water-impermeable extruded polyethylene layers. The top layer contains white titanium dioxide pigment that provides higher reflectivity than barium sulfate; the bottom layer is transparent and formulated to counteract the curl induced by the emulsion, which is coated on top o
25、f the pigmented layer.Prints on fibre paper have the advantage of having demonstrated long-term stability from years of practical experience in both dark storage and in reasonable display conditions. Proper processing and cleanliness or lack of contamination are important. Diluted toning solutions h
26、ave been used successfully to enhance stability (see Annex A).Prints on an RC paper base offer the advantages of higher wet strength, reduction in washing and drying times, lower consumption of processing chemicals, better dimensional stability, lower curl, and freedom from cockle and other effects
27、of differential shrinkage. As with fibre-base materials, toning has been used successfully to enhance stability. However, they can suffer from stability-related problems such as light-induced image discolouration, silver mirroring, yellowing and cracking of the polyethylene layer (see References 16,
28、 17, 18 and 19).This International Standard only applies to prints in dark storage since an applicable test for light-induced image deterioration has not been agreed upon. One reason for this has been that different brands of RC papers, or papers manufactured at different periods, have exhibited wid
29、ely varying stability characteristics. It has been very difficult to reconcile all of the observed differences in behaviour in a relatively simple standardized test (see Annex B).The image layer of most black-and-white prints is a gelatin coating containing a dispersion of light-sensitive silver hal
30、ide crystals that are selectively converted into metallic silver grains by an image-forming exposure and chemical processing. Gelatin is a natural polymer that has been the preferred binder for photographic materials since the 1880s because it has proven to be the best protective colloid for the pre
31、cipitation, growth and controlled suspension of silver crystals and for the formation of a dry, flexible image layer during a subsequent coating operation. Gelatin also can be hardened to reduce its swelling and susceptibility to physical damage, without blocking the absorption and desorption of aqu
32、eous processing solutions required for image formation and removal or stabilization of chemical by-products (see References 20 and 21).Converting the metallic silver to a complex or pre-oxidized form of silver will improve image stability. Many toner solutions have been designed to accomplish this,
33、such as selenium, sepia, gold, brown and poly-toners. For example, in the case of sepia toner treatment, the silver is converted from oxidizable metallic silver to a stable silver sulfide.The storage stability and useful life of reflection black-and-white prints depends on their physical and chemica
34、l properties, as well as on the conditions under which they are stored. For many years, the term “archival medium” was used to designate a recording material that can be expected to retain information forever so that it can be retrieved without significant loss when properly stored. However, there i
35、s no such material and it is a ISO 2012 All rights reserved vBS ISO 18929:2012ISO 18929:2012(E)term no longer employed for material or systems specifications of International Standards. Another reason for abandonment of the term is the multiplicity of meanings that it acquired over the years, rangin
36、g from “preserving information forever” to “temporary storage of actively used information”. The unambiguous term used in this International Standard is “life expectancy” (LE), defined as the length of time that information is predicted to be retrievable in a system after storage. For example, a des
37、ignation of LE-100 indicates that the information can be retrieved without significant loss after at least 100 years. Reflection prints are classified according to their LE designation in this International Standard.vi ISO 2012 All rights reservedBS ISO 18929:2012INTERNATIONAL STANDARD ISO 18929:201
38、2(E)Imaging materials Wet-processed silver-gelatin type black-and-white photographic reflection prints Specifications for dark storage1 ScopeThis International Standard establishes the specifications for silver-gelatin photographic reflection prints intended for dark storage. It covers silver-gelati
39、n print types of all weights.This International Standard applies to wet-processed black-and-white silver-gelatin photographic prints, including those that have been chemically treated (with a gold, selenium, sulfur, or other chemical treatment bath) to improve the permanence of the silver image. It
40、also applies to silver-gelatin prints processed by a monobath, which includes thiosulfate as a fixing agent followed by a conventional wash.This International Standard is not applicable to instant black-and-white photographic prints, stabilization-processed black-and-white prints (those where the un
41、developed silver halide has been chemically converted and not removed), or thermally processed black-and-white prints. It does not apply to colour or dye-based photographic prints, nor to prints that have been processed by a monobath using other than a thiosulfate-type fixing solution, or prints whe
42、re the silver salts are rendered more soluble by means other than thiosulfate.Laminated and adhesive mounted reflection prints, prints on poly (ethylene terephthalate) support, and prints that have been displayed are also excluded from this International Standard.2 Normative referencesThe following
43、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 5-3, Photography and graphic technology Density measurements
44、 Part 3: Spectral conditionsISO 5-4, Photography and graphic technology Density measurements Part 4: Geometric conditions for reflection densityISO 18907, Imaging materials Photographic films and papers Wedge test for brittlenessISO 18917, Photography Determination of residual thiosulfate and other
45、related chemicals in processed photographic materials Methods using iodine-amylose, methylene blue and silver sulfideTAPPI T494 om, Tensile breaking properties of paper and paperboard (using constant rate of elongation apparatus)3 Terms and definitionsFor the purposes of this document, the following
46、 terms and definitions apply.3.1archival mediummaterial that can be expected to preserve images forever, so that such images can be retrieved without significant loss when properly storedNOTE As no such material exists, this is a deprecated term and as such is not to be used in International Standar
47、ds for imaging materials or system specifications. ISO 2012 All rights reserved 1BS ISO 18929:2012ISO 18929:2012(E)3.2emulsionimage or image-forming layer(s) of silver halide photographic films, papers, and plates3.3life expectancyLErating for the life expectancy of recording materials and associate
48、d retrieval systemsNOTE 1 The number following the LE symbol is a prediction of the minimum life expectancy in years for which information can be retrieved without significant loss when stored in the conditions defined in the relevant standards. For example, LE-100 indicates that the information can
49、 be retrieved after at least 100 years storage.NOTE 2 The actual useful life of black-and-white paper is very dependent upon the existing storage conditions (see ISO 18902 and ISO 18920).3.4reflection print supportwhite, opaque support for the image-forming and auxiliary layers of a photographic print, intended for viewing by reflected light3.5treated silver imagesilver image that has been given a specific treatment, either during or after processing, to modify colour or increase stability4 Safety and op
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