1、 Reference number ISO 9848:2003(E) ISO 2003INTERNATIONAL STANDARD ISO 9848 Second edition 2003-12-01 Photography Source document microfilms Determination of ISO speed and ISO average gradient Photographie Microfilms de prises de vue Dtermination de la sensibilit ISO et du contraste moyen ISO ISO 984
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5、ow. ISO 2003 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 either ISO at the address below or ISOs member body
6、in the country of the requester. 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 9848:2003(E) ISO 2003 All rights reserved iiiContents Page Foreword
7、 iv Introduction v 1 Scope 1 2 Normative references . 1 3 Terms and definitions. 1 4 Sampling and storage. 2 5 Test method. 2 5.1 Principle . 2 5.2 Safelights . 2 5.3 Exposure 2 5.4 Processing. 4 5.5 Densitometry . 4 5.6 Evaluation 4 6 Product classification. 5 6.1 ISO speed. 5 6.2 ISO average gradi
8、ent 5 6.3 Accuracy 7 7 Product marking and labelling. 7 7.1 Speed 7 7.2 Average gradient. 7 7.3 General. 7 Annex A (informative) Use of ISO speed values 8 Bibliography . 9 ISO 9848:2003(E) iv ISO 2003 All rights reservedForeword ISO (the International Organization for Standardization) is a worldwide
9、 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
10、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 Standards are drafted in acc
11、ordance 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 International Standard requ
12、ires 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 9848 was prepared by Technica
13、l Committee ISO/TC 42, Photography. This second edition cancels and replaces the first edition (ISO 9848:1993), which has been technically revised. ISO 9848:2003(E) ISO 2003 All rights reserved vIntroduction This International Standard describes the method for determining the ISO speed and ISO avera
14、ge gradient of camera negative microfilms exposed with an incandescent tungsten source at a distribution temperature of 2 650 K 100 K (to simulate “undervolted” photoflood). The ISO speed and ISO average gradient determined by applying this International Standard are for film/process systems, not ju
15、st the film alone. The sensitometric characteristics of microfilm are dependent on the process conditions (developer, time, temperature, agitation, etc.) and some films will provide satisfactory results only in specific processes. Therefore, process conditions are not specified in this International
16、 Standard. They should be specified when the sensitometric values are quoted in manufacturers literature to enable proper interpretation. Because of “reciprocity law failure”, it is desirable to specify the exposure time used when quoting ISO speed and ISO average gradient values to ensure proper in
17、terpretation. Source document microfilming cameras do not have a “standard” exposure time. The exposure time used in evaluating the sensitometric characteristics of the film should be the same as that for which the film is intended to be used. The alternative of using only one exposure time in this
18、International Standard could be misleading if the film produces other results at its “end use” exposure time. If the film is used in a variety of applications, speed and contrast values at a range of exposure times may be helpful to the user. Typical light sources for microfilms include tungsten, xe
19、non and fluorescent. Since xenon and fluorescent sources are not yet standardized they are not included in this International Standard, but will be incorporated in the document when standardized. Due to spectral output differences, ISO values determined by using tungsten sensitometric exposure canno
20、t be used for applications where fluorescent or xenon illumination are used. The effective density of film images depends on the geometry of the optical system in which they are used. Many source document microfilms are used as “masters” for producing copies by contact printing, thereby requiring di
21、ffuse density measurements. When film is viewed on a microfilm “reader”, projection densitometry is more appropriate. Since the more critical end use is the former, this International Standard specifies diffuse density. Spectral conditions of the density measurement must also be specified. Printing
22、density characteristics are dependent upon the spectral sensitivity of the print film chosen for use as well as the spectral energy distribution of the printing light source. These parameters are determined by “end use” system requirements. Since no standard printing conditions have been agreed to o
23、r defined in this document, the use of printing density is precluded and visual density measurements will, therefore, be used as a compromise. The speed point density (1,20 above minimum density) was selected as a compromise of the proper image background densities. Since microfilms have medium to h
24、igh average gradients, exposure latitude is rather narrow. Thus, the speed value should be considered “approximate” and used only as a guide for initial testing. For critical work, the final exposure should be determined by testing the film over a range of exposures and the optimum chosen. A measure
25、ment of contrast is provided by the average gradient which relates the line density to the background density. This measurement correlates with the visual appearance of the recorded image and should aid users in selecting the best film for their application. This International Standard is concerned
26、primarily with the evaluation of a few characteristics of source document microfilms that are especially important in using the product. Therefore, the test method, sensitometric criteria and sampling procedures can prove inadequate for controlling quality in a film manufacturing operation. Since sp
27、eed and contrast vary greatly depending on exposure time, illuminant quality and process conditions, it is important for the user to consult the film manufacturer regarding the film and sensitometric characteristics that fit their application. INTERNATIONAL STANDARD ISO 9848:2003(E) ISO 2003 All rig
28、hts reserved 1Photography Source document microfilms Determination of ISO speed and ISO average gradient 1 Scope This International Standard specifies a method for determining the ISO speed and ISO average gradient of black-and-white camera negative photographic films used for first generation micro
29、filming of source documents at exposure times typically found with tungsten sources. These source documents include any handwritten or printed alphanumeric and line documents such as books, periodicals, business correspondence, and engineering drawings. The value-rating system described in this Inte
30、rnational Standard is only useful to the consumer if his exposure illumination is from an incandescent tungsten source as described in 5.3.3. It is not intended to include pictorial or continuous tone reproduction, computer output microfilm (COM), reversal processed or direct positive films or other
31、 films exposed by non-tungsten sources such as laser or cathode ray tube. The ISO speed and ISO average gradient values obtained by applying this International Standard are intended for practical use in comparing film/process combinations and for computing exposures. 2 Normative references The follo
32、wing referenced documents are indispensable for the application of this 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: Geometri
33、c conditions for transmission density ISO 5-3, Photography Density measurements Part 3: Spectral conditions ISO 554, Standard atmospheres for conditioning and/or testing Specifications ISO 6728, Photography Camera lenses Determination of ISO colour contribution index (ISO/CCI) 3 Terms and definition
34、s For the purposes of this document, the following terms and definitions apply. 3.1 speed quantitative measure of the response of the photographic material to radiant energy for the specified conditions of exposure, processing, density measurement and analysis 3.2 exposure H time integral of illumin
35、ance measured on the plane of the film surface NOTE 1 In the International lighting vocabulary 3 , H is defined as the luminous exposure. In this International Standard, “luminous exposure” is simply referred to as “exposure”. ISO 9848:2003(E) 2 ISO 2003 All rights reservedNOTE 2 Exposure is measure
36、d in lux seconds. NOTE 3 Exposure is often expressed in log 10 H units. 3.3 average gradient G slope of a line drawn between two specified points on the sensitometric curve 3.4 minimum density D minminimum density value obtainable from an unexposed sample of the same product processed simultaneously
37、 with the sample exposed for determining the sensitometric curve 4 Sampling and storage In determining the ISO speed and ISO average gradient of a product, it is important that the samples evaluated yield the average results obtained by users. This requires evaluating several different batches perio
38、dically under the conditions 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
39、 to ensure the proper calibration of equipment and processes. The basic objective in selecting and storing samples as described above is to ensure the film characteristics are representative of those obtained by a user at the time of use. 5 Test method 5.1 Principle Samples are exposed and processed
40、 as specified in 5.3 and 5.4, respectively. Density measurements are obtained from the resultant images to produce a sensitometric curve from which values are taken and used to determine ISO speed and ISO average gradient. See Figure 1. 5.2 Safelights To eliminate the possibility of safelight illumi
41、nation affecting the sensitometric results, all films shall be handled in complete darkness during sensitometric exposing and processing. 5.3 Exposure 5.3.1 Sampling conditions During exposure, the samples shall be at a temperature of 23 C 2 C and a relative humidity of (50 5) %. See ISO 554. 5.3.2
42、Type of sensitometer The sensitometer shall be a non-intermittent, illuminance-scale type. ISO 9848:2003(E) ISO 2003 All rights reserved 3Key X log 10 H, lux seconds Y ISO standard visual diffuse transmission density 1 average gradient 2 minimum density Figure 1 Sensitometric curve 5.3.3 Radiant ene
43、rgy quality ISO speed shall be determined using an incandescent tungsten source at a distribution temperature of 2 650 K 100 K (to simulate “undervolted” photoflood) as modified by the spectral transmittance of the standard camera lens as described in ISO 6728. Speed and average gradient determined
44、for other illuminants will be different. ISO speed shall be specified for use without a filter in front of the camera lens. If film is used with colour filtration in front of the camera lens, an “equivalent” speed number can be used to determine the exposure of the film with that filtration. ISO spe
45、ed does not apply to the filtered condition. ISO 9848:2003(E) 4 ISO 2003 All rights reserved5.3.4 Modulation The total range of spectral diffuse transmission density of each area of the light modulator throughout the wavelength interval from 400 nm to 700 nm shall not exceed 5 % of the average densi
46、ty obtained over the same interval or 0,03 density, whichever is greater. In the interval from 360 nm to 400 nm, 10 % of this same average density, or 0,06 density, whichever is greater, is acceptable. If a stepped increment modulator is used, the base 10 logarithm of the exposure increment shall no
47、t be greater than 0,15. 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 continuous variable modulator is used, the change of exposure with distance along the test strip shall be uniform and shall not be
48、greater than 0,02 log 10 H per millimetre. 5.3.5 Exposure time The exposure time shall correspond with the usage practice for the particular film tested. Since the speed of the film can be dependent on exposure time because of reciprocity law failure, the exposure time used for determining the ISO s
49、peed shall be specified. 5.4 Processing 5.4.1 Conditioning of samples In the time interval between exposure and processing, the samples shall be kept at 23 C 2 C and a relative humidity of (50 5) %. The processing shall be completed in not less than 3 h and not more than 4 h after exposure. 5.4.2 Processing specifications No processing specifications are described in this International Standard in recognition of the wide range of chemicals and equipment used. The ISO speed values provided by film manufac
