1、BRITISH STANDARD BS ISO 18915:2000 Imaging materials Methods for the evaluation of the effectiveness of chemical conversion of silver images against oxidation ICS 37.040.20 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBS ISO 18915:2000 This British Standard, having been prep
2、ared under the direction of the Consumer Products and Services Sector Committee, was published under the authority of the Standards Committee and comes into effect on 15 March 2001 BSI 03-2001 ISBN 0 580 37029 1 National foreword This British Standard reproduces verbatim ISO 18915:2000 and implement
3、s it as the UK national standard. It supersedes BS ISO 12206:1995 which is withdrawn. The UK participation in its preparation was entrusted to Technical Committee CPW/42, Photography, which has the responsibility to: A list of organizations represented on this committee can be obtained on request to
4、 its secretary. Cross-references The British Standards which implement international publications referred to in this document may be found in the BSI Standards Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Find” facility of the BSI Standards E
5、lectronic Catalogue. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. aid enquirers to und
6、erstand the text; present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed; monitor related international and European developments and promulgate them in the UK. Summary of pages This document compri
7、ses a front cover, an inside front cover, the ISO title page, pages ii to v, a blank page, pages 1 to 16, an inside back cover and a back cover. The BSI copyright date displayed in this document indicates when the document was last issued. Amendments issued since publication Amd. No. Date CommentsRe
8、ference number ISO 18915:2000(E) INTERNATIONAL STANDARD ISO 18915 First edition 2000-12-15 Imaging materials Methods for the evaluation of the effectiveness of chemical conversion of silver images against oxidation Matriaux pour image Mthodes dvaluation de lefficacit de la conversion chimique des im
9、ages argentiques contre loxydationISO 18915:2000(E) ii ISO 18915:2000(E)iii Contents Page Foreword.iv Introduction.v 1 Scope 1 2 Normative references 1 3 Terms and definitions .1 4 Dichromate bleach test .2 5 Hydrogen peroxide incubation test .3 Annex A (informative) Numbering system for related Int
10、ernational Standards8 Annex B (informative) Variable in silver stabilizing treatments .10 Annex C (informative) Significance of the test methods.11 Annex D (normative) Correction of density values .14 Bibliography16 Figure 1 Drawing of collar and baffles.4 Figure 2 Desiccator jar components5 Figure
11、3 Assembled desiccator jar.5ISO 18915:2000(E) iv 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
12、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
13、 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 3. Draft International Standards adopted by the technical committees are circulated to the member bodies for v
14、oting. 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 International Standard may be the subject of patent rights. ISO shall not be held responsible for identifyin
15、g any or all such patent rights. International Standard ISO 18915 was prepared by Technical Committee ISO/TC 42, Photography. This first edition cancels and replaces ISO 12206:1995, of which it constitutes a minor revision. This International Standard is one of a series of International Standards de
16、aling with the physical properties and stability of imaging materials. To facilitate identification of these International Standards, they are assigned a number within the block from 18900 18999 (see annex A). Annex D forms a normative part of this International Standard. Annexes A, B and C are for
17、information only.ISO 18915:2000(E)v Introduction Silver-gelatin photographs have been used extensively for recording and preserving information of lasting value in all fields of human activity. The long-term stability of these records has become of increasing concern in recent years, because image a
18、nd support degradation have been found with accelerating frequency in photographic collections and archives. ISO has published documents on various aspects of the stability and preservation of black-and-white silver-gelatin photographic materials. ISO 18901: 1) Imaging materials Processed silver-gel
19、atin type black-and-white film Specifications for stability, provides test methods and criteria for the physical properties, permissible residual processing chemicals, and the image quality of films. ISO 18911:2000, Imaging materials Processed safety photographic films Storage practices, deals with
20、the conditions required for maintaining and preserving the integrity of photographic films during storage. ISO 18902 2) , Imaging materials Processed photographic films, plates and papers Filing enclosures and storage containers, pertains to the materials used in contact with stored photographic mat
21、erials. If photographic film meets the material and processing specifications of ISO 18901 and is stored in accordance with ISO 18902 and ISO 18911, excellent stability will be obtained. Similarly, photographic paper prints should be stored in accordance with ISO 18920:2000, Imaging materials Proces
22、sed photographic reflection prints Storage practices, and processed photographic plates in accordance with ISO 18918:2000, Imaging materials Processed photographic plates Storage practices. However, in practical situations it is not always possible to control the storage conditions, particularly wit
23、h respect to contaminants. Atmospheric pollutants such as peroxides, sulfur dioxide, ozone and nitrogen dioxide are very detrimental to silver images (see 1 in the bibliography). Such environmental pollutants are of increasing concern in our industrial society. They can cause oxidation of the silver
24、 with consequent silver migration. This results in image fading, silver mirroring and redox blemishes (see 2 and 3 in the bibliography). Oxidizing agents that diffuse out of enclosure materials cause similar defects. Recent studies have shown that silver images can be made resistant to oxidizing pol
25、lutants by chemically treating the silver to form silver sulfide (see 4 in the bibliography) or silver selenide (see 5 in the bibliography), or by substitution of the silver by gold (see 6 in the bibliography). Such treatments are recommended when it is not possible to ensure the absence of contamin
26、ants, or when the importance of the image justifies the added expense. This International Standard is an adjunct to the processing requirements and describes methods for evaluating the effectiveness of various treatments which impart greater stability to silver images. 1) To be published. (Revision
27、of ISO 10602:1995) 2) To be published. (Revision of ISO 10214:1991)INTERNATIONAL STANDARD ISO 18915:2000(E)1 Imaging materials Methods for the evaluation of the effectiveness of chemical conversion of silver images against oxidation 1 Scope 1.1 This International Standard describes methods for evalu
28、ating the effectiveness of chemical conversion treatments intended to increase the resistance of wet-processed silver images to oxidation. The treatment may be applied as part of the original processing, or it may be a post-processing treatment. This International Standard does not recommend general
29、 or specific treatments for silver images. Likewise, treatment temperature, times and replenishment rates are outside the scope of this International Standard. Factors to be considered in a stabilizing treatment are discussed in informative annex B. Two test methods are described: the “dichromate bl
30、each test“ and the “hydrogen peroxide incubation test“ (see 7 in the bibliography). The significance of each is discussed in informative annex C. 1.2 This International Standard is applicable to silver-gelatin images coated on supports of either plastic, paper or glass. 2 Normative references The fo
31、llowing normative documents contain provisions which, through reference in this text, constitute provisions of this International Standard. For dated references, subsequent amendments to, or revisions of, any of these publications do not apply. However, parties to agreements based on this Internatio
32、nal Standard are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest edition of the normative document referred to applies. Members of ISO and IEC maintain registers of currently valid Internati
33、onal Standards. ISO 5-2: 3 , Photography Density measurements Part 2: Geometric conditions for transmission density. ISO 5-3:1995, Photography Density measurements Part 3: Spectral conditions. ISO 5-4:1995, Photography Density measurements Part 4: Geometric conditions for reflection density. 3 Terms
34、 and definitions For the purposes of this International Standard, the following terms and definitions apply. 3.1 treated silver images silver images that have been given a specific treatment, either during or after processing, to increase their stability 3 To be published. (Revision of ISO 5-2:1991)
35、ISO 18915:2000(E) 2 3.2 toned silver images silver images that have been given a specific treatment, either during or after processing, to modify their colour 4 Dichromate bleach test 4.1 Principle This test consists of dissolving the treated silver image and measuring the retained density. This ret
36、ained density is proportional to the silver that has been chemically converted to a non-bleachable compound, or has been substituted by a non-bleachable element. 4.2 Reagents 4.2.1 Bleach solution A bleach solution shall be prepared by dissolving 90 g of anhydrous potassium dichromate in 1 litre of
37、water. Subsequently, 96 ml of concentrated sulfuric acid shall be slowly added with constant stirring. WARNING Avoid contact with the eyes, skin, and clothing. Wash thoroughly after handling. In case of contact, flush eyes and skin with water. Obtain medical attention immediately. Take care to dispo
38、se of dichromate bleach solution in accordance with national and local regulations for hazardous waste disposal. 4.2.2 Clearing solution The clearing solution shall be prepared by dissolving 100 g of sodium sulfite in 1 litre of water. 4.3 Specimen preparation Six uniform-density patches shall be pr
39、epared on the treated silver material with densities (D) ranging in approximately equal increments from 0,1 above D min to D max . The exact size of the patches is not critical, provided they cover the aperture of the densitometer and are easy to handle. 4.4 Procedure Measure the treated silver imag
40、e on the six uniform-density patches and on the D min for status A blue density. Densities shall be measured on a densitometer having spectral conformance to ISO 5-3. The densitometer shall have geometric conformance to ISO 5-2 for photographic films and plates, and geometric conformance to ISO 5-4
41、for photographic papers. Then immerse the specimen in the bleach solution (4.2.1) for 30 s at (20 5) o C, rinse it in water for 2 s, and clear for 30 s in the clearing solution (4.2.2). Then rinse the specimen in water, dry it and remeasure the status A blue density. 4.5 Calculation The percent dens
42、ity retention is calculated by dividing the blue density after bleaching by the original blue density (after treatment, but before bleaching) and multiplying by 100. Make this calculation for all six uniform-density patches. With some photographic materials, particularly photographic paper prints, b
43、leaching can cause an increase in the D min . The percent density retention shall be corrected for any D min increase, as shown in normative annex D.ISO 18915:2000(E)3 4.6 Significance The retained density is an approximation of the percentage of silver image that has been converted into substances
44、which are not affected by oxidants or pollutants. A treatment that results in 65 % density retention or more after bleaching for all six density patches is considered a stable image. NOTE This density retention value is based on the fact that since two-thirds of the image will not be affected by oxi
45、dants, there would be no loss of information. Treatments that result in a lower percent density retention may also be very stable, depending upon the image density and type of chemical conversion. 5 Hydrogen peroxide incubation test 5.1 Principle This test consists of exposing the treated silver ima
46、ges to hydrogen peroxide vapour and measuring the resultant change in density. A small change in density represents an image that is resistant to peroxides. 5.2 Reagents 5.2.1 Hydrogen peroxide, reagent grade, 2 % (m/m) solution, freshly prepared from a 30 % stock solution. WARNING Hydrogen peroxide
47、 is very corrosive. Caution should be used in handling hydrogen peroxide solutions. The stock solutions should be kept refrigerated in vertical vented bottles and kept away from combustibles. Gloves and protective clothing should be worn. Take care to dispose of hydrogen peroxide solutions according
48、 to national and local waste disposal regulations. 5.2.2 Potassium chloride, saturated solution. 5.2.3 Potassium chloride, dry solid. 5.3 Apparatus 5.3.1 Glass desiccator jar, having a nominal inside diameter of 150 mm and a capacity of 2 litres. 5.3.2 Ground plastic desiccator lid 4 ,fi t t edw i t
49、 hafa n . The fan motor is attached to the top surface of the desiccator lid with the shaft going through the lid to the fan mounted on the inside surface. There shall be four fan blades, each approximately 25 mm in length. The fan shall rotate at approximately 2 000 r/min. 5.3.3 Plastic collar 4) , that shall fit snugly inside the desiccator on which the specimens are mounted. The collar shall be roughly 80 mm in height with an inside diameter of 135 mm and a wall thickness of approximately 7 mm. The colla
