ISO INTERNATIONAL STANDARD 5799 Second edition 1991-08-01 Photography --- Direct-exposing medical and dental radiographic film/process systems - Determination of IsO speed and ISO average gradient Photographie --. Ensembles film/traitement destines a la radiographie medicale sans ecran et a la radiographie dentaire -- Determination de la sensibilite isO et du contraste moyen IsO Reference number 1SO 5799:1991(E) nsefromIHS ISO 5799:1991(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 technical committees. Each member body interested in a subject for 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. so 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 Inter- bodies casting a vote. International Standard Iso 5799 was prepared by Technical Committee Iso/TC 42, Photography. This second edition cancelsand freplacesthefirst edition (isO 5799:1981), which has been technically revised. Annexes A, B, C and D of this International Standard are for information only. C ISO 1991 All rights reserved. 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-1211Geneve 20·Switzerland Printed in Switzerland Not for Resale d without license from IHS ISO 5799:1991(E) Introduction This revision of iso 5799 has been primarily necessitated by the deci- sion to adopt the recommendation of the International Commission of Radiation Units and Measurements to use the gray as a measure of X and , radiation in place of coulombs per kilogram of air. This has re- quired changing the speed constant. The International Standard now includes updated references, and speed and average gradient tables compatible with the format of other radiographic film standards. ili No reproduction or networking permitted without license from IHS Not for Resale