ISO INTERNATIONAL STANDARD 7187 Second edition 1995-12-15 Photography -- Materials for direct-positive colour-print cameras --- Determination of ISO speed Photographie - Surfaces sensibles pour appareils photographiques donnant directement une épreuve positive en couleur -- Determination de lasensibilite/so ISO Reference number ISO 7187:1995(E) No reproduction or networking permitted without license from IHS Not for Resale ISO7187:1995(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 and non-governmental, in liaison with ISO, also take part in the work. IsO collaborates closely with the International Electrotechnical Commission (tEC) 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 a vote. International Standard iSO 7187 was prepared by Technical Committee ISO/TC 42, Photography. This second editioncancelsandreplaces thefirst edition (Is0 7187:1983), which has been technically revised to include several new definitions (clause 3) and a distinction between speed, IsO speed and IsO speed of a product (clause 6). Annex A of this International Standard is for information only. @ISO1995 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 Standardizatior No reproduction or networking permitted without license from IHS Not fr esale ISO7187:1995(E) @ISO Introduction The increased use of in-camera processed colour-print materials, often referred to as "instant print", and the introduction of equipment to permit method for determining the speed of this type of product. This Inter- national Standard applies to any directly viewed reflection colour-print material made by camera exposure of the original scene onto a photo- sensitive material and subsequent diffusion transfer of a dye image within material similarly exposed, but later processed outside of the camera by a process other than diffusion transfer of the dyed image. It does not apply to copying or duplicating For diffusion-transfer materials, the speed and colour of prints depend on the ambient temperature during diffusion. Usually, speed problems as well as serious colour mismatches will occur in prints made at temperatures direct viewing of reflection prints are specified in iSO 3664. The sensitometric method specified in this International Standard gives IsO speeds that are in close agreement with film speeds obtained by making practical camera exposures. These speeds follow the f/16 daylight rule; that is, the Iso speed is the reciprocal of the exposure time, in is set at f/16 in direct sunlight for an average front-lighted scene with a solaraltitudebetween35°and50° When these IsO speeds are used in conjunction with exposure meters conforming to IsO 2720, resultant pictures will be of optimum exposure. For an average scene, the optimum exposure will be approximately midway between the least exposure and the greatest exposure producing satisfactory prints at normal viewing illuminance levels. The exposure exposureandonehalf stopforoverexposure. Copyright Internatinal Organizalion for Standardization ili No reproduction or networking permited without license from IHS Not for Resale