ISO INTERNATIONAL STANDARD 10636 First edition 1994-05-01 Photography Processing chemicals - Specifications for anhydrous sodium thiosulfate and sodium thiosulfate pentahydrate Photographie Produits chimiques pour traitement - Spécifications relatives au thiosulfate de sodium anhydre et au thiosulfate de sodium pentahydrate No reproduction or networking permitted without license from IHS Not for Resale IS010636:1994(E) Foreword IsO (the International Organization for Standardization) is a worldwide federation of national standards bodies (isO member bodies). The work represented on that committee. International organizations, governmental 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 International avote International Standard ISO 10636 was prepared by Technical Committee !SO/TC 42, Photography. ISO 1994 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanicai, including photocopying and microfilm, without permission in writing from the publisher. International Organization for Standardization Case Postale 56 . CH-1211 Geneve 20 · Switzerland Printed in Switzerland CopyrightInternational Organization for Standardization No reproduction or networking permitted without license from IHS Not for Resale c IsO ISO 10636:1994(E) Introduction 0.1 This International Standard is one of a series that establishes criteria of purity for chemicals used in processing photographic materials. General test methods and procedures cited in this International Standard are compiled in parts 1, 3, 5, 7 and 10 of IsO 10349. This International Standard is intended for use by individuals with a work- 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 and other protective apparel such as face masks or aprons where appropriate. Normal pre- cautions required in the performance of any chemical 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 hand- ling 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 require- ments for the suitability of a photographic-grade chemical. The tests cor- relate with undesirable photographic effects. Purity requirements are set as low as possible consistent with these photographic effects. These cri- teria are considered the minimum requirements necessary to assure suf- ficient purity for use in photographic processing solutions, except that if the purity of a commonly available grade of chemical exceeds photo- graphic 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 lim- ited to amounts which will not unduly reduce the assay. All tests are per- furnished for use. Although the ultimate criterion for suitability of such a shorter, more economical test methods described 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 ex- ists that another chemical or mixture of chemicals co