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1、BRITISH STANDARD BS ISO 5990:1996 Implementation of ISO 5990:1996 Photography Processing chemicals Specifications for potassium sulfite, 650 g/l aqueous solution ICS 37.040.30 Licensed Copy: sheffieldun sheffieldun, na, Sun Nov 26 12:51:34 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS ISO 5990:1996
2、This British Standard, having been prepared under the direction of the Consumer Products and Services Sector Board, was published under the authority of the Standards Board and comes into effect on 15 February 1997 BSI 12-1998 The following BSI references relate to the work on this standard: Committ
3、ee reference CPW/42 Draft for comment 94/408985 DC ISBN 0 580 26618 4 Committees responsible for this British Standard The preparation of this British Standard was entrusted to Technical Committee CPW/42 Photography, upon which the following bodies were represented: British Photographic Association
4、British Institute of Professional Photography British Film Institute Royal Photographic Society SIRA Limited The following bodies were also represented in the drafting of the standard, through subcommittees and panels: British Institute of Non-destructive Testing Chemical Industries Association Depa
5、rtment of the Environment Water Directorate Amendments issued since publication Amd. No.DateComments Licensed Copy: sheffieldun sheffieldun, na, Sun Nov 26 12:51:34 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS ISO 5990:1996 BSI 12-1998i Contents Page Committees responsible Inside front cover Nation
6、al foreword ii Foreword ii Introduction 1 1 Scope 1 2 Normative references 1 3 General 2 4 Requirements 2 5 Reagents and materials, including glassware 2 6 Sampling 2 7 Test procedures 2 Table 1 Summary of requirements 2 Licensed Copy: sheffieldun sheffieldun, na, Sun Nov 26 12:51:34 GMT+00:00 2006,
7、 Uncontrolled Copy, (c) BSI BS ISO 5990:1996 ii BSI 12-1998 National foreword This British Standard reproduces verbatim ISO 5990:1996 and implements it as the UK national standard. It supersedes BS 6618:1985 which is withdrawn. This British Standard is published under the direction of the Consumer P
8、roducts and Services Sector Board whose Technical Committee CPW/42 has the responsibility to: aid enquirers to understand the text; present to the responsible international committee any enquiries on interpretation, or proposals for change, and keep UK interests informed; monitor related internation
9、al and European developments and promulgate them in the UK. NOTEInternational and European Standards, as well as overseas standards, are available from Customer Services, BSI, 389 Chiswick High Road, London W4 4AL. A British Standard does not purport to include all the necessary provisions of a cont
10、ract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, the ISO title page, page ii, pa
11、ges 1 to 5 and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover. Licensed Copy: sheffieldun sheffieldun, na, Sun Nov 26 12:51:34 GMT+00:00 2006, Uncontrolled Copy, (c) B
12、SI Licensed Copy: sheffieldun sheffieldun, na, Sun Nov 26 12:51:34 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS ISO 5990:1996 ii Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing Intern
13、ational 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 organizations, governmental and non-governmental, in liaison with
14、 ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an
15、International Standard requires approval by at least 75 % of the member bodies casting a vote. International Standard ISO 5990 was prepared by Technical Committee ISO/TC 42, Photography. This second edition cancels and replaces the first edition (ISO 5990:1983), which has been technically revised. L
16、icensed Copy: sheffieldun sheffieldun, na, Sun Nov 26 12:51:34 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS ISO 5990:1996 BSI 12-19981 Introduction 0.1 This International Standard is one of a series that establishes criteria of purity for chemicals used in processing photographic materials. General
17、 test methods and procedures cited in this International Standard are compiled in parts 1, 5, 9, 11 and 12 of ISO 10349. This International Standard is intended for use by individuals with a working knowledge of analytical techniques, which may not always be the case. Some of the procedures utilize
18、caustic, toxic or otherwise hazardous chemicals. Safe laboratory practice for the handling of chemicals requires the use of safety glasses or goggles, rubber gloves and other protective apparel such as face masks or aprons where appropriate. Normal precautions required in the performance of any chem
19、ical procedure are to be exercised at all times but care has been taken to provide warnings for hazardous materials. Hazard warnings designated by a letter enclosed in angle brackets “ ” are used as a reminder in those steps detailing handling operations and are defined in ISO 10349-1. More detailed
20、 information regarding hazards, handling and use of these chemicals may be available from the manufacturer. 0.2 This International Standard provides chemical and physical requirements for the suitability of a photographic-grade chemical. The tests correlate with undesirable photographic effects. Pur
21、ity requirements are set as low as possible consistent with these photographic effects. These criteria are considered the minimum requirements necessary to assure sufficient purity for use in photographic processing solutions, except that if the purity of a commonly available grade of chemical excee
22、ds photographic processing requirements and if there is no economic penalty in its use, the purity requirements have been set to take advantage of the availability of the higher-quality material. Every effort has been made to keep the number of requirements to a minimum. Inert impurities are limited
23、 to amounts which will not unduly reduce the assay. All tests are performed on samples “as received” to reflect the condition of materials furnished for use. Although the ultimate criterion for suitability of such a chemical is its successful performance in an appropriate use test, the shorter, more
24、 economical test methods described in this International Standard are generally adequate. Assay procedures have been included in all cases where a satisfactory method is available. An effective assay requirement serves not only as a safeguard of chemical purity but also as a valuable complement to t
25、he identity test. Identity tests have been included whenever a possibility exists that another chemical or mixture of chemicals could pass the other tests. All requirements listed in clause 4 are mandatory. The physical appearance of the material and any footnotes are for general information only an
26、d are not part of the requirements. 0.3 Efforts have been made to employ tests which are capable of being run in any normally equipped laboratory and, wherever possible, to avoid tests which require highly specialized equipment or techniques. Instrumental methods have been specified only as alternat
27、ive methods or alone in those cases where no other satisfactory method is available. Over the past few years, great improvements have been made in instrumentation for various analyses. Where such techniques have equivalent or greater precision, they may be used in place of the tests described in thi
28、s International Standard. Correlation of such alternative procedures with the given method is the responsibility of the user. In case of disagreement in results, the method called for in the specification shall prevail. Where a requirement states “to pass test”, however, alternative methods shall no
29、t be used. 1 Scope This International Standard establishes criteria for the purity of photographic-grade potassium sulfite, 650 g/l aqueous solution, and specifies the test methods to be used to determine the purity. 2 Normative references The following standards contain provisions which, through re
30、ference in this text, constitute provisions of this International Standard. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this International Standard are encouraged to investigate the possibility of applying t
31、he most recent editions of the standards indicated below. Members of IEC and ISO maintain registers of currently valid International Standards. Licensed Copy: sheffieldun sheffieldun, na, Sun Nov 26 12:51:34 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS ISO 5990:1996 2 BSI 12-1998 ISO 10349-1:1992,
32、Photography Photographic-grade chemicals Test methods Part 1: General. ISO 10349-5:1992, Photography Photographic-grade chemicals Test methods Part 5: Determination of heavy metals and iron content. ISO 10349-9:1992, Photography Photographic-grade chemicals Test methods Part 9: Reaction to ammoniaca
33、l silver nitrate. ISO 10349-11:1992, Photography Photographic-grade chemicals Test methods Part 11: Determination of specific gravity. ISO 10349-12:1992, Photography Photographic-grade chemicals Test methods Part 12: Determination of density. 3 General 3.1 Physical properties Potassium sulfite (K2SO
34、3) as a 650 g/l aqueous solution has the form of a clear, colourless or almost colourless liquid. Potassium sulfite has a relative molecular mass of 158,27. 3.2 Hazardous properties Potassium sulfite, 650 g/l aqueous solution, is not hazardous when handled with normal precautions. Avoid contact with
35、 acids. 3.3 Storage Potassium sulfite solution shall be stored in a closed container at room temperature. 4 Requirements A summary of the requirements is shown in Table 1. 5 Reagents and materials, including glassware All reagents, materials and glassware shall conform to the requirements specified
36、in ISO 10349-1 unless otherwise noted. The hazard warning symbols used as a reminder in those steps detailing handling operations are defined in ISO 10349-1. These symbols are used to provide information to the user and are not meant to provide conformance with hazardous labelling requirements as th
37、ese vary from country to country. 6 Sampling See ISO 10349-1. 7 Test procedures 7.1 Assay 7.1.1 Specification Content of K2SO3 shall be between 44,5 % (m/m) min. and 46,0 % (m/m) max. Table 1 Summary of requirements TestLimitSubclause International Standard in which test method is given Assay44,5 %
38、(m/m) min.7.1ISO 5990 46,0 % (m/m) max. Heavy metals content (as Pb)0,002 % (m/m) max.7.2ISO 10349-5 Iron content0,002 % (m/m) max.7.3ISO 10349-5 Reaction to ammoniacal silver nitrate To pass test7.4ISO 10349-9 Specific gravity or density: specific gravity1,445 min.7.5.1ISO 10349-11 1,460 max. densi
39、ty1,441 g/ml min.7.5.2ISO 10349-12 1,457 g/ml max. pH value of (1 + 9) solution8,0 to 10,07.6ISO 5990 Thiosulfate content (as S2O32) 0,006 % (m/m) max.7.7ISO 5990 Appearance of solutionClear and free from insoluble matter except for a slight flocculence 7.8ISO 5990 NOTEm/m = mass/mass Licensed Copy:
40、 sheffieldun sheffieldun, na, Sun Nov 26 12:51:34 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS ISO 5990:1996 BSI 12-19983 7.1.2 Reagents 7.1.2.1 Iodine (I2), standard volumetric solution of 0,05 mol/l (12,7 g/l) 1) 2). Weigh, to the nearest 0,001 g, 12,7 g of freshly sublimed iodine (DANGER: CO)3)
41、into a tared weighing flask. Add 36 g of potassium iodide (KI) and 100 ml of water. After solution is complete, add three drops of hydrochloric acid (7.1.2.5) (DANGER: CB), and dilute to l litre at 20 C in a volumetric flask. From the mass of iodine, m, calculate the concentration, c, in moles per l
42、itre, from c = m/254 7.1.2.2 Sodium thiosulfate (Na2S2O3), standard volumetric solution of 0,100 mol/l (15,8 g/l)1). 7.1.2.3 Salicylic acid (HOC6H4CO2H), 1 % (10 g/l) solution. Prepare a solution of 1 g of salicylic acid in 100 ml of water. 7.1.2.4 Starch indicator, 5 g/l solution. Stir 5 g of solub
43、le starch with 100 ml of 1 % salicylic acid solution (7.1.2.3). Then add 300 ml to 400 ml of boiling water and boil until the starch dissolves. Finally dilute to 1 000 ml with water. 7.1.2.5 Hydrochloric acid (HCl), (DANGER: CB). 7.1.3 Apparatus 7.1.3.1 Burette, of 50 ml capacity. 7.1.3.2 Pipette, o
44、f 25 ml capacity. 7.1.3.3 Pipette, of 50 ml capacity. 7.1.3.4 Magnetic stirrer and bar 7.1.4 Procedure Use either the back-titration method (7.1.4.1) or the direct-titration method (7.1.4.2). 7.1.4.1 Back-titration method Using a pipette (7.1.3.2), deliver 25,00 ml of the iodine solution (7.1.2.1) i
45、nto a glass stoppered flask. Weigh, to the nearest 0,000 1 g, a test portion of about 0,25 g and wash this into the flask. Add 5 ml of the hydrochloric acid (7.1.2.5) and titrate with the sodium thiosulfate (7.1.2.2) using the burette (7.1.3.1). Add 2 ml of the starch indicator (7.1.2.4) just before
46、 the endpoint. 7.1.4.2 Direct-titration method Weigh, to the nearest 0,000 1 g, a test portion of about 0,90 g. Using a pipette (7.1.3.3), deliver 50,00 ml of the iodine solution (7.1.2.1) into a completely dry 250 ml beaker that contains a magnetic stirring bar (7.1.3.4). While stirring the iodine
47、solution in the beaker, wash the test sample into the centre of the beaker. Avoid contact of the sample with the sides of the beaker. If the iodine is not decolorized after the sample addition, discard the trial and restart the procedure. If necessary, increase the test portion by 0,10 g. Wash down
48、the side walls of the beaker using about 2 ml of the starch indicator (7.1.2.4). Immediately titrate with the iodine solution (7.1.2.1) to the first permanent light-purple colour. Wash any iodine solution remaining on the burette tip into the solution with deionized water. If the titration exceeds 1
49、0 ml, repeat the test as this can result in test results lower than the actual assay. Adjust the sample appropriately. 7.1.5 Calculations 7.1.5.1 Back-titration method The assay, expressed as a percentage by mass of K2SO3, is given by 7,914(c150 c2V2)/m where 1) Commercially available analysed reagent solutions are recommended. 2) If solutions are to be prepared, see any quantitative analytical chemistry text. It is recommended that self-prepared iodine solutions be standardized before use. 3) Hazard warning codes ar