ISO INTERNATIONAL STANDARD 3943 Second edition 1993-02-01 Photography -- Processing chemicals Specifications for anhydrous sodium acetate Photographie -- Produits chimiques de traitement -- Specifications pour I'acetatedesodiumanhydre Referencenumber ISO3943:1993(E) No reproduction or networking permitted without license from IHS Not for Resale ISO 3943:1993(E) 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 which a technical committee has been established has the right to be represented on that committee. International organizations, govern- mental 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 national Standard requires approval by at least 75% of the member bodies casting a vote. International Standard Iso 3943 was prepared by Technical Committee ISO/TC 42, Photography. This second edition cancels and replaces the first edition (iso 3943:1976), which has been technically revised. C ISO 1993 All rights reserved. No part of this publication may be reproduced or utilized in any form perrnission in writing from the publisher. internationai Organization for Standardization CasePostale56·CH-1211Geneve20·Switzerland Printed in Switzerland No reproduction or networking permitted without license from IHS Not for Resale ISO3943:1993(E) Introduction o.1 This International Standard is one of a series that establishes cri- teria of purity for chemicals used in processing photographic materials General test methods and procedures cited in this International Stan- dard are compiled in parts 1, 3, 5, 6 and 7 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 caustic, toxic or otherwise hazardous chemicals. Safe laboratory practice for the handling of chemicals requires the use of safety glasses or goggles, rubber gloves propriate. Normal precautions required in the performance of any 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 information regarding hazards, handling and use of these chemicals may be available from the manufacturer. 0.2 This International Standard provides chemical and physical re- quirements for the suitability of a photographic-grade chemical. The tests correlate with undesirable photographic effects. Purity require- ments 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 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 to amounts which will not unduly reduce the condition of materials furnished for use. Alithough the ultimate criterion for suitability of such a chemical is its successful performance in an appropriate use test, the shorter, more economical test methods de- scribed in this International Standard are generally adequate. method is available. An effective assay requirement serves not only as a safeguard of chemical purity but also as a valuable complement to the identity test. Identity tests have been included whenever a possibility exists that another chemical or mixture of chemicals could pass the othertests All requirements listed in clause 4 a