ISO INTERNATIONAL STANDARD 3619 Second edition 1994-12-15 Photography - Processing chemicals - Specifications for ammonium thiosulfate solution Photographie - Produits chimiques de traitement - Spécifications relatives au thiosulfated'ammonium en solution ISO Referencenumber ISO 3619:1994(E) No reproduction or networking permitted without license from IHS Not for Resale ISO3619:1994(E) Foreword ISO (the International Organization for Standardization) is a worldwide preparing International Standards is normally carried out through isO technical committees. Each member body interested in a subject for which 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 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 3619 was prepared by Technical Committee ISO/TC 42. Photography. This second edition cancels and replaces the first edition (ISO 3619:1976), which has been technically revised. 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 mechanical, including photocopying and microfilm, without permission in writing from the publisher. InternationalOrganizationforStandardization Case postale 56 . CH-1211 Geneve 20 . Switzerland Printed in Switzerland for Standardizatior NorerouctiornetworkngprmitedithoutlicenefrmH Not for Resale @ ISO ISO 3619:1994(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 compiledinparts1,3,4,5,10,11and12ofIsO10349. 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 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 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 require- ments for the suitability of a photographic-grade chemical. The tests correlate with undesirabie photographic effects. Purity 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 exceeds 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 number of requirements to a minimum. Inert impurities are limited to amounts which will not unduly reduce the assay. All tests are performed use. Although the ultimate criterion for suitability of such a chemical is its successful performance in an appropriate use test, the shorter, more economical test methods described in this International Standard are generally adequate. Assay procedures have been included in all cases where a satis