ISO INTERNATIONAL STANDARD 3621 Second edition 1994-12-15 Photography Processing chemicals - Specifications for sodium tetraborate decahydrate Photographie -- Produits chimiques de traitement - Specifications relatives au tétraborate de sodium décahydraté ISO Reference number ISO3621:1994(E) No reproduction or networking permitted without license from IHS Not for Resale ISO 3621:1994(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 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 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 Standard requires approval by at least 75 % of the member bodies casting avote International Standard iSO 3621 was prepared by Technical Committee ISO/TC 42, Photography. which has been technically revised. ?ISO1994 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. Internationai Organization for Standardization Casepostale56.CH-1211Geneve20.Switzerland Printed in Switzerland 11 Copyright Int THS No reproduction or networking permitted without license from IHS Not fr Resale ISO 3621:1994(E) @ ISO 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, 5 and 9 of ISO 10349. This International Standard is intended for use by individuals with a workingknowledgeofanalyticaltechnigues,whichmaynotalwaysbethe 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 angle brackets, < >, are used as a reminder in those steps detailing handling operations and are defined in ISO 10349-1. Moredetailed information regarding hazards, handling and use of these chemicals may beavailablefromthemanufacturer 0.2 This International Standard provides chemical and physical require- ments for the suitability of a photographic-grade chemical. Thetests correlate with undesirable 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 thepurityofacommonlyavailablegradeofchemicalexceedsphotographic processing requirements and if there is no economic penalty in its use, the number of requirements to a minimum. Inert impurities are limited 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 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