1、 Reference number ISO 2240:2003(E) ISO 2003INTERNATIONAL STANDARD ISO 2240 Fourth edition 2003-10-15 Photography Colour reversal camera films Determination of ISO speed Photographie Films de prise de vue inversibles en couleur Dtermination de la sensibilit ISO ISO 2240:2003(E) PDF disclaimer This PD
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6、 ISO copyright office Case postale 56 CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail copyrightiso.org Web www.iso.org Published in Switzerland ii ISO 2003 All rights reservedISO 2240:2003(E) ISO 2003 All rights reserved iiiForeword ISO (the International Organization for Stand
7、ardization) 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
8、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. International St
9、andards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an I
10、nternational Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 224
11、0 was prepared by Technical Committee ISO/TC 42, Photography. This fourth edition cancels and replaces the third edition (ISO 2240:1994), which has been technically revised. ISO 2240:2003(E) iv ISO 2003 All rights reservedIntroduction The ISO speeds are intended to provide correct exposures with exp
12、osure meters conforming to ISO 2720, and, where applicable, automatic exposure controls for cameras conforming to ISO 2721; the resultant camera exposure will normally lead to colour transparencies or motion pictures of the best quality. For an average scene and average camera, the indicated camera
13、exposure will be approximately midway between the least exposure and the greatest exposure required to produce transparencies and motion-picture films suitable for viewing at normal luminance levels. For the purpose of this International Standard, the normal luminance of transparency illuminators is
14、 assumed to be that described in ISO 3664 with a ratio of direct-to-ambient luminance of about 40:1. The normal luminance of transparency projection screens is assumed to be about 137 cd/m 2 . Screen luminance of 8 mm Type R and 8 mm Type S (Super-8) motion-picture film projection is assumed to rang
15、e from approximately 40 cd/m 2(see ISO 2910) to 62 cd/m 2 . Therefore, it may be desirable to increase exposure by 25 % above that obtained by using the speed derived by following the sensitometric procedure described in this International Standard. Many camera manufacturers design and calibrate the
16、ir 8 mm Type R and 8 mm Type S motion-picture cameras with an adjustment which permits more exposure to compensate for the lower screen luminance of the usual projection conditions (see ISO 2721). INTERNATIONAL STANDARD ISO 2240:2003(E) ISO 2003 All rights reserved 1Photography Colour reversal camer
17、a films Determination of ISO speed 1 Scope This International Standard specifies the method for determining the ISO speed of colour reversal camera films producing continuous-tone pictorial images that are intended to be viewed on transparency illuminators or by projection as slides. It also applies
18、 to 8 mm and 16 mm motion-picture films used in non-professional applications. This International Standard is not applicable to professional motion-picture films regardless of their applications. 2 Normative references The following referenced documents are indispensable for the application of this
19、document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 5-2, Photography Density measurements Part 2: Geometric conditions for transmission density ISO 5-3, Photography Density measu
20、rements Part 3: Spectral conditions ISO 7589, Photography Illuminants for sensitometry Specifications for daylight, incandescent tungsten and printer 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 exposure H time integral of illuminance on t
21、he film NOTE 1 In the International lighting vocabulary 8 , H is defined as the luminous exposure. In this International Standard, “luminous exposure“ is simply referred to as “exposure“. NOTE 2 Exposure is measured in lux seconds. NOTE 3 Exposure is often expressed in log 10 H units. 3.2 speed quan
22、titative measure of the response of the photographic material to radiant energy for the specified conditions of exposure, processing, density measurement and analysis ISO 2240:2003(E) 2 ISO 2003 All rights reserved3.3 minimum density minimum density value obtainable following the process used in the
23、 ISO speed determination 4 Sampling and storage In determining the ISO speed of a product, it is important that the samples evaluated yield the average results obtained by users. This requires evaluating several different batches periodically under the conditions specified in this International Stan
24、dard. 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. To assure that all components of variance are included in the sampling plan, it is recommended that procedures
25、 such as those outlined in ISO Standards Handbook 7be used. The objective in selecting and storing samples as described above is to ensure the film characteristics are representative of those obtained by a photographer at the time of use. 5 Test method 5.1 Principle Samples are exposed and processed
26、 in the manner specified below. Density measurements are obtained from the resultant images to produce a sensitometric curve from which values are taken and used to determine ISO speed. 5.2 Safelights To eliminate the possibility of safelight illumination affecting the sensitometric results, all fil
27、ms shall be handled in complete darkness during sample preparation, exposing and processing. 5.3 Exposure 5.3.1 Sample conditions During exposure, the samples shall be equilibrated with air at a temperature of (23 2) C and a relative humidity of (50 5) %. 5.3.2 Type of sensitometer The sensitometer
28、shall be a non-intermittent, illuminance-scale type. 5.3.3 Radiant energy quality The appropriate illuminant for the particular film type being exposed shall conform to the specification given in ISO 7589. ISO speed may be determined using ISO sensitometric daylight, studio tungsten, or photoflood i
29、lluminants. Since the speed of film process combinations depends on the type of illuminant used, the illuminant should be specified in the instructions. ISO speed shall be specified for use without a filter in front of the camera lens. If a film is used with a colour filter in front of the camera le
30、ns, an “equivalent“ speed number can be used to determine the exposure of the film with the filter. ISO speed is not applicable to the filtered condition. 5.3.4 Modulation The total range of spectral diffuse transmission density with respect to the film plane of each area of the light modulator thro
31、ughout the wavelength interval from 400 nm to 700 nm shall not exceed 5 % of the average ISO 2240:2003(E) ISO 2003 All rights reserved 3density obtained over the same interval or 0,03 density, which ever is greater. In the interval from 360 nm to 400 nm, 10 % of this same average density or 0,06 den
32、sity, whichever is greater, is acceptable. If stepped increment modulation is used, the exposure increment shall not be greater than 0,15 log 10 H. The width and length of a single step shall be adequate to obtain a uniform density within the reading aperture specified for densitometry. If a continu
33、ous variable modulator is used, the change in exposure with distance along the test strip shall be uniform and not greater than 0,04 log 10 H per millimetre. 5.3.5 Exposure time The exposure time shall be between 5 s and 1/1 000 s corresponding to the usage practice for the particular film tested. S
34、ince the speed of film is dependent on exposure time because of reciprocity law failure, the exposure time used for determining ISO speed should be specified in use instructions. 5.4 Processing 5.4.1 Conditioning of samples In the time interval between exposure and processing, the samples shall be e
35、quilibrated with air at (23 2) C and a relative humidity of (50 5) %. The processing shall be completed in no fewer than 5 days and no more than 10 days after exposure for general-purpose films, and no fewer than 4 h and no more than 7 days for professional films. 5.4.2 Processing specifications No
36、processing specifications are described in this International Standard in recognition of the wide range of chemicals and equipment used. ISO speed provided by film manufacturers generally applies to the film when it is processed in accordance with their recommendations to produce the photographic ch
37、aracteristics specified for the process. Processing information shall be available from film manufacturers or others who quote ISO speed. This shall specify the chemicals, time, temperatures, agitation and procedure used for each of the processing steps and any additional information required to obt
38、ain the sensitometric results described. The values for speed obtained using various processing procedures can differ significantly. Although different speeds for a particular film can be achieved by varying the process, the user should be aware that other sensitometric and physical changes can also
39、 accompany the speed changes. 5.5 Densitometry ISO standard visual diffuse transmission density of the processed images shall be measured using a densitometer complying with the geometric conditions specified in ISO 5-2 and the spectral conditions specified in ISO 5-3. These conditions are designate
40、d: D T(90opal; S H : u 10; V T ) or D T(u10; S H : 90opal; V T ) Readings shall be made in a uniform area of the image, typically at least 1 mm from the edges of the exposures. ISO 2240:2003(E) 4 ISO 2003 All rights reserved5.6 Evaluation 5.6.1 Sensitometric curve The ISO standard visual diffuse tra
41、nsmission density values are plotted against the logarithm to the base 10 of the corresponding exposures (H) expressed in lux seconds, to obtain a sensitometric curve similar to that illustrated in Figure 1. 5.6.2 Minimum density The minimum density shall be determined from a film sample adequately
42、exposed to produce the minimum density possible and processed simultaneously with the sample exposed for determining the sensitometric curve. 5.6.3 Determination of H mand log 10 H mThe method for determining ISO speed is illustrated in Figure 1. Point P is located on the sensitometric curve at the
43、density of 0,20 above the minimum density. Point S is then located on the curve 2,00 above the minimum density to bracket the normal range of density in a typical transparency. In order to represent a reasonable reproduction of the scene, the slope of the line between points P and S should fall betw
44、een 1,4 and 1,8. The exposures H Pand H Scorrespond to points P and S, and are used to compute the exposure H mby use of the following formulae: 10 S 10 P 10 log log log 2 m H H H + = (1) or SP m H HH = (2) The exposure, H m , represents the exposure in lux seconds, used to determine the ISO speed.
45、ISO 2240:2003(E) ISO 2003 All rights reserved 5Key X log 10 H (H expressed in lux seconds) Y ISO standard visual diffuse transmission density 1 minimum density Figure 1 Sensitometric curve 6 Product classification 6.1 ISO speed 6.1.1 ISO speed scale The speed scales given in Table 1 are derived from
46、 Equations (3) and (4): 10 m S H = (3) o 10 10 11 0l o g m S H =+ (4) ( ) 10 11 0 l o g S =+ ISO 2240:2003(E) 6 ISO 2003 All rights reservedwhere S is the arithmetic speed; S ois the logarithmic speed. “ISO“ speed shall be obtained directly from log 10 H mby use of Table 1 which shows the correspond
47、ing rounded values of S and S o . 6.1.2 ISO speed of a product The ISO speed of a product (as distinguished from that of a specific sample) shall be based on the arithmetic mean of the logarithms of exposures, log 10 H mdetermined from several batches of the product when selected, stored and tested
48、as specified above (see Clauses 4 and 5). The ISO speed of a product with proper rounding is then determined from the average value of log 10 H mby use of Table 1. Since ISO speed is dependent on exposure and processing conditions, these should be indicated when quoting ISO speed values. 6.2 Accurac
49、y The calibration of the equipment and processes involved in determining film speed shall be adequate to ensure the absolute value of the error in log 10 H mis less than 0,05. 7 Product marking and labelling The speed of a product determined by the method described in this International Standard and expressed on the scales of Table 1 may be designated ISO speed and denoted in the form of ISO 100, ISO 21 or ISO 100/21. ISO 2240:2003(E) ISO 2003 All rights reserved 7Table 1 ISO speed Log
