ISO INTERNATIONAL STANDARD 422 Second edition 1994-10-15 Photography - Processing chemicals - Specifications for p-methylaminophenol sulfate Photographie - Produits chimiques de traitement - Spécifications pour le sulfate de p-methylaminophenol XX ISO Reference number ISO422:1994(E) No reproduction or networking permitted without license from IHS Not for Resale ISO 422:1994(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 atechnical 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 a vote. International Standard IsO 422 was prepared by Technical Committee ISO/TC 42, Photography. This second edition cancels and replaces the first edition (ISO 422:1976) 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. International Organization for Standardization Case postale 56 . CH-1211 Geneve 20 . Switzerland Printed in Switzerland ii No reproduction or networking permitted without license from IHS Not for Resale ISO 422:1994(E) @ ISO Introduction O.1 This International Standard is one of a series that establishes criteria of purity for chemicals used in processing photographic materials. General compiled in parts 1, 4, 5 and 8 of ISO 10349. ThisInternational Standard is intended for use byindividuals with a working knowledge of analytical techniques, which may not always be the case. Some of the procedures utilize caustic, toxic or otherwise hazardous the use of safety glasses or goggles, rubber gloves and other protective apparel suchasfacemasksorapronswhereappropriate. Normal be exercisedatall timesbut carehasbeentakentoprovidewarningsfor hazardous materials. Hazard warnings designated by a letter enclosed in 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 correlatewithundesirablephotographiceffects.Purityrequirementsare 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 onsamples"asreceived"toreflectthe condition of materialsfurnishedfor use.Althoughthe ultimatecriterionforsuitabilityofsuchachemicalis its successful performance in an appropriate use test, the shorter, more economical test methods described in this International Standard are generalyadequate. method is available. An effective assay requirement serves not only as a safeguard of chemical purity but also as a valuable complement to the identitytest.ldentitytestshavebeenincludedwheneverapossibility tests. All requirements listed in clause 4 are mandator