1、INTERNATIONAL STANDARD ISO 7187 Second edition 1995-12-15 Photography - Materials for direct-positive colour-print cameras - Determination of ISO Speed Photographie - Surfaces sensibles pour appareils pho tographiques donnant directement une epreuve positive en couleur - Determination de Ia sensibil
2、ite ISO Reference number ISO 7187:1995(E) ISO 7187:1995(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 committ
3、ees. Esch 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, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the Int
4、ernational 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
5、 bodies casting a vote. International Standard ISO 7187 was prepared by Technical Committee ISOnC 42, Photography. This second edition cancels and replaces the first edition (ISO 7187:1983), which has been technically revised to include several new definitions (clause 3) and a distinction between Sp
6、eed, ISO Speed and ISO Speed of a product (clause 6). Annex A of this International Standard is for information only. 0 ISO 1995 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronie or mechanical, including
7、 photocopying and microfilm, without Permission in writing from the publisher. International Organization for Standardization Case Postale 56 l CH-l 21 “l Geneve 20 l Switzerland Printed in Switzerland ii ISO ISO 7187:1995(E) Introduction The increased use of in-Camera processed colour-print materia
8、ls, often referred to as “instant print”, and the introduction of equipment to permit their use in general cameras makes it desirable to establish a Standard method for determining the Speed of this type of product. This Inter- national Standard applies to any directly viewed reflection colour-print
9、 material made by Camera exposure of the original Scene onto a photo- sensitive material and subsequent diffusion transfer of a dye image within the same material or to a second receiver material. lt also applies to any material similarly exposed, but later processed outside of the Camera by a proce
10、ss other than diffusion transfer of the dyed image. lt 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
11、 at temperatures beyond the range recommended by the manufacturer. The conditions of 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 pract
12、ical Camera exposures. These Speeds follow the f/16 daylight rule; that is, the ISO Speed is the reciprocal of the exposure time, in seconds, which gives the best quality print when the Camera lens aperture is set at fl16 in direct sunlight for an average front-lighted Scene with a solar altitude be
13、tween 35O and 50”. 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 satisfa
14、ctory prints at normal viewing illuminance levels. The exposure latitude for satisfactory prints is approximately one half stop for under- exposure and one half stop for overexposure. This page intentionally left blank INTERNATIONAL STANDARD ISO ISO 7187:1995(E) Photography - Materials for direct-po
15、sitive colour-print cameras - Determination of ISO Speed 1 Scope This International Standard specifies a method for de- termining the ISO Speed of materials for direct- positive colour-print cameras when used in a Camera for pictorial photography. lt also applies to diffusion- transfer and conventio
16、nal colour-print materials di- rectly exposed in cameras and processed in or out of the Camera. This International Standard does not apply to materials used for copying or duplicating applications. 2 Normative references The following Standards contain provisions which, through reference in this tex
17、t, constitute provisions of this International Standard. At the time of publication, the editions indicated were valid. All Standards are subject to revision, and Parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent edit
18、ions of the Standards indicated below. Members of IEC and ISO maintain registers of currently valid International Standards. ISO 5-3: 1995, Photography - Density measurements - Part 3: Spectral conditions. ISO 5-4: 1995, Photography - Density measurements - Part 4: Geometrie conditions for reflectio
19、n density. ISO 7589: 1984, Photography - Illuminants for sensi- tometry - Specifica tions for dayligh t and incan- descen t tungs ten. 3 Definitions For the purposes of this International Standard, the following definitions apply. 3.1 exposure, H l): Time integral of the illuminance on the sensitize
20、d material, measured in lux seconds. Exposure is often expressed in logloH units. . 3.2 Speed, S: Quantitative measure of the response of the photographic material to radiant energy for the specified conditions of exposure, processing and im- age measurement. 3.3 direct-positive processing: Any one-
21、exposure photographic process which results in a positive im- age directly from the original subject matter. 3.4 diffusion transfer: Photographit process whereby the image moves as a consequence of development to a receiving medium to form (usually) a positive image for viewing. 3.5 reversal process
22、ing: Photographit process in which the exposed negative latent image is formed, but that, either by uniform post-exposure or by fogging process chemicals, tan be made to yield a positive reproduction. 4 Sampling and storage In determining the ISO Speed of a product, it is im- portant that the sample
23、s evaluated yield the average results obtained by users. This will require evaluating 1) CIE Publication No. 17.4 defines “Iuminous exposure, H”. In this International Standard, “Iuminous exposure” is simply referred to as “exposure”. 1 ISO 7187:1995(E) ISO several different batches periodically und
24、er the con- ditions specified in this International Standard. Prior to evaluation, the samples shall be stored according to the manufacturers recommendations for a length of time to simulate the average age at which the product is normally used. Several independent evaluations shall be made to ensur
25、e the proper calibration of equipment and processes. The basic objective in sel- ecting and storing samples as described above is to ensure that the product characteristics are represen- tative of those obtained by a user at the time of use. 5 Test method 5.1 Principle Samples are exposed in a sensi
26、tometer and pro- cessed in the manner specified below. Density measurements are obtained from the resultant image to produce a sensitometric curve from which values are taken and used to determine the ISO Speed. 5.2 Safelights To eliminate the possibility of safelight illumination af- fecting the se
27、nsitometric results, all sensitized ma- terials shall be handled in complete darkness during exposing and processing. 5.3 Exposure 53.1 Sample condition During exposure, the samples shall be at a tempera- ture of 23 “C & 2 “C and a relative humidity of (50+5)%. Th is is the recommended atmosphere an
28、d normal tolerantes specified in ISO 554. 5.32 Type of sensitometer The sensitometer shall be a non-intermittent, illuminance-scale type. 5.3.3 Radiant energy quality The illuminant for the particular product type being exposed shall conform to the appropriate illuminant specified in ISO 7589. 5.3.4
29、 Filters ISO Speed shall be specified for use without a filter in front of the Camera lens. If a product is used with a colour filter in front of the Camera lens, an “equivalent” Speed number may be used to deter- mine the exposure of the product with the filter. ISO Speed does not apply to the filt
30、ered condition. 5.3.5 Modulation The total range of spectral diffuse transmission den- sity with respect to the film plane of each area of the light modulator throughout the wavelength interval from 400 nm to 700 nm shall not exceed 5 % of the average density obtained over the same interval or 0,03
31、density, whichever is the greater. In the interval from 360 nm to 400 nm, l0 % of this same average density or 0,06 density, whichever is the greater, shall not be exceeded. If a stepped modulator is. used, the logarithm to the base 10 of the exposure increment shall not be greater than O,l5. The wi
32、dth and length of a Single step shall be adequate to obtain a uniform density within the reading aperture specified for densitometry. If a continuously variable modulator is used, the log- arithm to the base 10 of the Change in exposure with distance along the test Strip shall be uniform and not be
33、greater than 0,04 per millimetre. An area of the product shall be given sufficient ex- posure to produce the minimum density possible. 5.3.6 Exposure time Exposure time shall be between 5 s and l/l 000 s, typical of the usage practice for the sensitized ma- terial tested. Typical exposure times are
34、l/l 000 s to 1/25 s for a daylight-type print material and l/l 00 s to 5 s for exposure with tungsten illumination. Since the Speed of the sensitized material tan be dependent on the exposure time because of reciprocity law failure, the exposure time used in determining the ISO Speed should be speci
35、fied in the instructions for use. 5.4 Processing 5.4.1 Conditioning of samples In the time interval between exposure and processing, the samples shall be kept at a temperature of 23 “C + 2 “C and a relative humidity of (50 zt 5) %. For products designed for in-Camera processing, the processing shall
36、 be initiated within 2 min after ex- posure. For products requiring conventional processing in separate equipment, processing should be initiated within 2 h after exposure. 5.42 Processing specifications The temperature for processing products designed for in-Camera processing shall be 23 “C + 0,5 “
37、C. The temperature for processing products designed for conventional processing using separate equipment shall be that recommended by the manufacturers. . No additional processing specifications are described in this International Standard in recognition of the wide range of chemicals and equipment
38、used. ISO Speed provided by sensitized product manufacturers 2 0 ISO ISO 7187:1995(E) generally applies to the product when it is processed in accordance with their recommendations to produce the photographic characteristics specified for the process. Process information shall be available from the
39、manufacturers or others who quote ISO Speed values. This shall specify the chemicals, times, tem- peratures, agitation, equipment and procedure used for each of the processing Steps, and any additional information required to obtain the sensitometric re- sults described. The values for Speed obtaine
40、d using various processing procedures tan differ significantly. Although different Speeds for a particular product tan be achieved by varying the process, the user should be aware that other sensitometric and physical changes tan also accompany the Speed changes. Density measurements shall be made 2
41、4 h k 4 h after processing. During this interval, the samples shall be stored at a temperature of 23 “C + 2 “C and a relative humidity of (50 + 5) %. 5.6 Evaluation 5.6.1 Sensitometric curve The ISO Standard visual reflection density values shall be plotted against the logarithm to the base 10 of th
42、e corresponding exposures (H), expressed in lux sec- onds, to obtain a sensitometric curve similar to that illustrated in figure 1. 5.5 Densitometry 5.6.2 Minimum density ISO Standard visual reflection density of the pro- cessed images shall be measured using a densi- tometer complying with the geom
43、etric requirements specified in ISO 5-4 and the spectral requirements specified in ISO 5-3. Readings shall be made in a uniform area of the image. The minimum density shall be determined from a Sample of the material adequately exposed to produce the minimum density possible and processed simul- tan
44、eously with the Sample exposed for determining the sensitometric curve. 3 .- u k u c fu t v) Ei 1 - density I og&rn -1 logloH Wnlux seconds) Figure 1 - Sensitometric curve ISO 7187:1995(E) 6 Product classification 6.1 Speed calculation Raw Speed values are derived from the formula: where H, is the e
45、xposure, in lux seconds, required to produce a density of 0,50 above the minimum density. 6.1.1 ISO Speed The ISO Speed shall be obtained directly from loglOH, by use of table 1, which effectively translates it to one of the designated ISO Speeds in the ISO Speed scale. The procedure is to first det
46、ermine loglOH, as in figure 1. The appropriate loglOH, range is then selected from the two columns on the left side of table 1 and the corresponding ISO Speed is found in the right-hand column of table 1. 6.1.2 ISO Speed of a product The ISO Speed of a product (as distinguished from that of a specif
47、ic Sample) shall be based on the arithmetic mean of the loglOH, values determined from several batches of the product when selected, stored and tested as specified in clause 4 and sub- clauses 5.4 and 5.5. The ISO Speed of a product with proper rounding is then determined from the average value of l
48、oglOH, by use of table 1. 6.2 Accuracy The calibration of the equipment and processes involved in determining product Speed shall be adequate to ensure that the absolute value of the error in loglOH, is less than 0,05. 7 Product marking and labelling The Speed of a product determined by the method s
49、pecified in this International Standard and expressed on the scale given in table 1 may be designated the ISO Speed and denoted in the form “ISO 100”. ISO Since the ISO Speed is dependent on the exposure and processing conditions, these should be indicated when quoting ISO Speed values. Table 1 - ISO Speed scale “b41 ISOspeed 4 ISO 7187:1995(E) Annex A (informative) Bibliography 1 ISO 554: 1976, Standard atmospheres for conditioning and/or testing - Specifications. 2 ISO 2720: 1974, Photography - General purpose photographic exposure meters (photoelectric type) - Guide to pro
