HG/T 2911-1997 Determination of ISO sensitivity and ISO average slope of original microfilm
Some standard content:
ICS37.040.20
Registration No. 415—1997
Chemical Industry Standard of the People's Republic of China
HG/T2911 1997
idtISo9848:1993
Photography-Source document microfilms-Determination ofISO speed and ISO average gradient1997-05-23 Issued by
Ministry of Chemical Industry of the People's Republic of China
1997-10-01Implementation
HG/T2911-1997
This standard is equivalent to ISO9848:1993 (E) "Photography-Original microfilm-Determination of ISO sensitivity and ISO average slope". The difference is: three international standard numbers that have been converted into Chinese standards have been changed in the referenced standards. From the date of publication of this standard, the content related to original microfilm in HG/T2173-1991 will be abolished. Appendices A, B and C of this standard are indicative appendices. This standard was proposed by the Technical Supervision Department of the Ministry of Chemical Industry. This standard is under the jurisdiction of China Lucky Film Company, the technical unit responsible for standardization of the Photosensitive Materials Department of the Ministry of Chemical Industry. The drafting units of this standard are China Lucky Film Company, Tianjin Photosensitive Materials Company and Shanghai Photosensitive Materials Company. The main drafters of this standard are Huang Zhizhong, Zhao Lixiang and Wang Benying. HG/T2911—1997
ISO Foreword
JSO (International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of formulating international standards is usually completed by ISO technical committees. Each member body interested in the subject of an established technical committee has the right to participate in the technical committee. Governments and Non-governmental international organizations may also participate in this work after contacting ISO. The draft international standards determined by the technical committee shall be circulated to the member groups for voting. At least 75% of the members who voted shall agree before they can be published as international standards.
International Standard ISO9848 was developed by ISO/TC42 Photography Committee. Appendices A and B of this international standard are only indicative appendices. HG/T2911-1997
ISO Introduction
This national standard describes the method for determining the ISO sensitivity and ISO average slope of microfilm negatives using incandescent tungsten filament film light with a color temperature in the range of 2650K±100K (simulating "undervoltage strong light"). The ISO sensitivity and ISO average slope determined by this international standard are The ISO average slope is for the film/processing system, not just for the film. The sensitometric characteristics of original microfilm depend on the processing conditions (developer, development time, development temperature and agitation, etc.). Some films can only produce satisfactory results when processed according to the specified process. Therefore, this international standard does not specify processing conditions. Manufacturers should specify processing conditions when marking sensitometric values in their technical data to ensure the correct transmission of information. Due to the "reciprocity failure" in the United States, the correct way to indicate ISO sensitivity and ISO average slope values is to indicate the warm light time used at the same time. Original microfilm cameras may not have a "standard exposure time". The warm light time used to measure the film's photosensitivity should be consistent with the film's actual future use. If only one exposure time is specified in this International Standard, errors may result when the film produces other results due to its "final exposure time". If the film is used in different applications, it will be useful to give the sensitivity and average slope for different exposure times within a certain range. Typical light sources for microfilm photography include tungsten, xenon and fluorescent. However, because xenon and fluorescent light sources have not been standardized, these two light sources are not included in this International Standard at present and will be included when they are standardized. Because of the difference in spectral output, the ISO value determined by using tungsten sensitometer cannot be used in applications where fluorescent or xenon lamps are used.
The effective density of the film image depends on the geometric conditions of the optical system used. Many original microfilms are used as "masters" for the production of prints by contact printing. Therefore, diffuse density measurement is required. When the film is to be viewed on a microfilm "reader", projection (unidirectional) density measurement is more appropriate. Since the most critical end use is the former, this International Standard specifies diffuse density. The spectral conditions for density measurement must also be specified. The print density characteristics depend on the spectral sensitivity of the film selected and on the spectral power distribution of the printing light source. These parameters are determined by the requirements of the "end use" system. Since this standard does not adopt or specify standard printing conditions, this standard does not use print density, but uses the visual density measurement disk as a wraparound solution. The sensitivity point density (minimum density plus 1.20) is used to represent the appropriate density of the image background. Because the original microfilm has a medium to high average slope, its instantaneous light tolerance is quite narrow. Therefore, the sensitivity value should be considered an "approximate number" and should only be used as a benchmark for starting experiments. For demanding work, the final exposure should be determined by a series of exposure tests and selection of films. The average slope is a measure of contrast. It reflects the relationship between line density and background density. It is directly related to the visual perception of the recorded image and will help users choose the best film for their use. This article International Standards deal primarily with the evaluation of a few properties that are particularly important when using original microfilms. Therefore, the test methods, sensitization specifications and sampling procedures described in this standard may not be suitable for quality control of film production operations. Since sensitivity and contrast are closely related to exposure time, substrate quality and processing conditions, it is important for users to inquire with film manufacturers about which films and sensitometric properties are suitable for their use. Chemical Industry Standard of the People's Republic of China
Original microfilms
Determination of ISO sensitivity and ISO average slope HG/ T 2911 -- 1997
idtIsO9848:1993
Photography-Source document microfilmns-Dctermination ofISO spccd and ISO average slope gradient1 Scope
This standard specifies a method for determining ISO sensitivity and ISO average gradient for first generation tungsten photographic negative films for microfilming of originals exposed primarily with tungsten filament light sources. These originals include all written documents or printed documents with text or lines, such as books, periodicals, business correspondence, and engineering drawings. The index rating system described in this standard is only useful for users who use incandescent tungsten filament light sources as specified in 5.3.3 for exposure illumination. The rating system is not applicable to reproduction of pictures or continuous tones, computer input microfilm (COM), reversal master or direct positive film, or other films exposed with non-filament light sources such as lasers or cathode ray tubes.
The ISO sensitivity and ISO average gradient values measured by this standard are intended for practical comparison of film/processing combination systems and for calculating exposure.
2 Referenced Standards
The following standard contains the conditions The text, through reference in this standard, constitutes the provisions of this standard. At the time of publication of the standard, the versions shown are valid. All standards will be revised. Parties using this standard should explore the possibility of using the latest versions of the following standards: GB11500-89 Geometric conditions for photographic transmission density measurement (neg ISO5.2: 1991) GB11501-89 Spectral conditions for photographic density measurement (ncq ISO5.3: 1984) GB/T12823-91 Terms, symbols, coordinate coefficients and function representation methods for photographic density measurement (neg ISO5.11984)
IS0554: 1976 Standard atmospheres for balance and/or testing - Specification ISO2720: 1974 Photography - General photographic exposure meter (photoelectric type) - Product specification guide ISO6728: 1983 Photography - Camera lens - Determination of ISO color contribution index (I5O/CCI) 3 Definitions
This standard adopts the following definitions.
3.1 Sensitivity
A quantitative measure of the response of a photographic material to radiant energy under specified conditions of exposure, processing, density measurement, and analysis.
3.2 Exposure disc, H\)
1) In the "International Dictionary of Service Terms". This term is defined as the amount of light exposure H. In this standard, H is simply referred to as exposure. Approved by the Ministry of Chemical Industry of the People's Republic of China on May 23, 1997 and implemented on October 1, 1997
HG/T 2911-1997
The exposure time integral value of the illuminance measured on the film surface plane, expressed in lux seconds. Optical discs are often used in logarithmic tables with a base of 10. 3.3 Average slope
The slope of the line connecting two specific points on the characteristic curve, 3.4 Minimum density, Dmm
The minimum density value measured on the unexposed sample of the same product processed at the same time as the exposed sample for measuring the photosensitive characteristic curve. 4 Sampling and storage
When determining the ISO sensitivity and ISO average slope of a product, it is important to be able to measure the average result obtained by the user from the measured sample. This will require the periodic measurement of several batches of different products under the conditions specified in this standard. Prior to the measurement, the samples should be stored for the time recommended by the manufacturer, in order to simulate the average shelf life of the product in normal use. The instrumentation and processing should be properly calibrated for each measurement. The fundamental purpose of the above sampling and sample storage requirements is to ensure that the film properties measured represent the properties of the film used by the user.
5 Test method
5.1 Principle
The illumination and processing of the sample are carried out in accordance with 5.3 and 5.4 respectively. The density is measured from the resulting image and a characteristic curve is plotted. The data obtained from the characteristic curve can be used to calculate the ISO sensitivity and ISO average slope (see Figure 1). ISO standard visual diffuse density
Average slope
Minimum density
Sensitivity measurement curve| |tt||5.2 Safelight
Noise light IgH
(H, lux+m)
In order to eliminate the influence of safelight on the sensitometric results, all films should be operated in total darkness during sensitometric exposure and processing.
5.3 Exposure
5.3.1 Sampling conditions
HG/T29[1—199]
During exposure, the samples should be kept in an environment with a temperature of 23°±2 and a relative humidity of (50±5)% (see TSO554). 5.3.2 Type of photosensitive instrument
The photosensitive instrument should be a non-intermittent dimming photosensitive instrument. 5.3.3 Quality of radiant energy
The ISO sensitivity should be determined using a tungsten filament light source with a distributed color temperature of 2650K±100K (simulating a strong light with insufficient voltage). The color temperature of this light source is the same as the distributed color temperature of the light source obtained after the spectral transmittance of the standard camera lens described in ISO6728 (see Appendix C) is corrected. The sensitivity and average slope measured with other illuminants will be different. ISO sensitivity is only applicable when there is no filter in front of the camera lens. If a color filter is added in front of the camera lens, the "equivalent sensitivity value" can be used to determine the light of the film with the filter. ISO sensitivity is not applicable to the condition with the filter. 5.3.4 Light modulator
In the entire wavelength range of 400nm to 700nm, the spectral diffuse transmission density in each area of the light modulator should not exceed 5% of the average density obtained in the same area, or the average density obtained. Compared with the density, it should not be greater than 0.03. In the range of 360nm ~ 400zm, it is allowed to be no more than 10% of the average density or no more than 0.06 of the density value. If a step-by-step reverse-increment light modulator is used, the logarithmic light gain disk with a base of 10 should not be greater than 0.15. The width and length of each level should ensure that the density in the reading light hole specified in the density measurement is uniform. If a continuously variable light modulator is used, the change in exposure along the direction of the test strip with respect to distance should be uniform, and the change should not be greater than 0.021gH per millimeter, 5. 3.5 Exposure time
The exposure time should be equivalent to the exposure time of the film being tested. Since sensitivity is related to exposure time due to reciprocity failure, the exposure time used to determine ISO sensitivity should be stated. 5.4 Processing
5.4.1 Sample conditioning
After exposure, the sample should be kept at a temperature of 23±2 and a relative humidity of (50±5)% before processing. Processing should be completed within no less than 3 hours and no more than 4 hours after exposure. 54.2 Processing specifications
This standard Processing specifications are not described in this document, and selection is not made from a wide range of available processing chemicals and equipment. The ISO sensitivity values quoted by film manufacturers will generally apply only to films processed according to the manufacturer's recommended process to produce the photographic properties stated. Processing information can be obtained from film manufacturers or other entities that quote ISO sensitivity. The processing information should specify the chemicals, time, temperature spots, stirring devices and stirring procedures used in each processing step, as well as other information to obtain the sensitometric results stated. The sensitivity values obtained from different processing procedures will vary considerably. Although changing the processing of a film can get different sensitivities, users should understand that other photosensitive properties and physical properties will also change with the change of sensitivity. 5.5 Density measurement
The ISO standard visual transmission density of the processed image should be measured by a densitometer that meets the geometric conditions specified in GB11500 and the spectral conditions specified in GB11501. The density value should be read at least 1mm away from the boundary in the exposure area.
5.6 Evaluation
5.6.1 Sensitometric curve
The ISO standard visual transmission density of the processed image should be measured by a densitometer that meets the geometric conditions specified in GB11500 and the spectral conditions specified in GB11501. The density value should be read at least 1mm away from the boundary in the exposure area.
5.6.1 Sensitometric curve
The standard diffuse radiation density value of SO is plotted against the logarithmic value of the corresponding maximum light intensity (H) (lux·second) with a base of 10, and a sensitivity characteristic curve similar to Figure 1 is obtained.
5.6.2 Minimum density
The minimum density should be measured from the unexposed sample. The unexposed sample should be processed at the same time as the exposed sample for measuring the sensitivity characteristic curve. 5.6.3 Determination of ISO sensitivity and ISO average slope The determination method of ISO sensitivity and ISO average slope is shown in Figure 1. ISO sensitivity is measured from point m, which is located at the minimum density of the curve plus 1.20 density points. The ISO average slope is the slope of the line connecting point m and point n, which is located at the minimum density of the curve plus 3
IIG/T 2911-1997
0.1 density points. The exposure required to produce point m and point density is recorded as H. and H. respectively. 6 Product classification
6.1Iso sensitivity
& 1.1IS0 sensitivity scale
The ISO sensitivity listed in Table 1 includes the exposure values of representative product samples. The original sensitivity of these sensitivity values is calculated by the following formula:
Wherein: S——original arithmetic sensitivity:
——exposure required to produce minimum density plus 1.20 density, Table 1 ISO sensitivity table
ISO sensitivity
(arithmetic)
M 1 6G0
M 1 000
HG/T2911—1997
Table 1 (End)
ISO sensitivitybzxz.net
6.1.2 The ISO sensitivity of the sample
can be directly found from Table 1 by igH to obtain the ISO sensitivity after normalization of the original sensitivity value. The capital letter "M" should be added before the ISO sensitivity value to indicate that the sensitivity is measured using this standard rather than other standards. When using a camera equipped with a camera that can change the shutter speed to achieve automatic shutter control, that is, an AE camera, the sensitivity calculated by the above formula should be divided by 5 and then the normalized sensitivity should be found in Table 1, see Appendix A Discussion
6.1.3 ISO sensitivity of products
The ISO sensitivity of products (different from specific samples) sampled, stored and tested in accordance with the provisions of this standard shall be calculated by taking the arithmetic mean of the logarithmic instantaneous light values 1gI. measured for different batches of the product. After obtaining the arithmetic mean of the logarithmic instantaneous light values IgH of products of different batches, the ISO sensitivity (after appropriate normalization) shall be determined from this average value in Table 1.
6.2 ISO average slope
6.2.1 ISO average slope scale
Table 2 gives the ISO average slope values of typical product samples. The original average slope values of these samples are calculated according to the following formula:
1. 20 -- 0. 10
IgH.- IgH.
Where: the original average slope of the sample;
Hm-the exposure required to produce the minimum density plus 1.20 density; H.-the exposure required to produce the minimum density plus 0.10 density, 5
6.2.2 ISO average slope of sample
HG / T 2911 -- 1997
Table 2 ISO average slope
ISO average slope
The ISO average slope of a sample [after appropriate adjustment] should be obtained directly from the (1gH, -igH,) value of the sample in Table 2. The ISO average slope number should be preceded by a capital letter *G" (e.g. G1.6). 6.2.3 Average slope of the product
The average slope of the product (as distinguished from the average slope of a specific sample) should be determined by the arithmetic mean of the values (IgH.-lgH.) obtained from different batches of products, which are selected, stored and tested in accordance with the provisions of this standard. This arithmetic mean is then used to obtain the ISO average slope of the product (after appropriate normalization) from Table 2. 6.3 Accuracy
The instruments and processing conditions used to determine the sensitivity should be calibrated to ensure that the absolute value of the error for 1gH is less than 0.05, and the absolute value of the error in the average slope should be less than 5% of the average slope value obtained. 7 Product marking and labeling
7.1 Sensitivity
The sensitivity of the products listed in Table 1 measured by the method described in this standard can be called ISO sensitivity and expressed in the M400\ format.
7.2 Average slope
The average slope of the products listed in Table 2 measured by the method described in this standard can be called ISO average slope and expressed in the M400\ format.
7.3 General
HG/T2911—1997
Since the sensitivity and average slope are determined not only by the film product but also by the exposure time and the processing conditions for image development, the exposure time and processing conditions should be explained when indicating the sensitivity and average slope. Appendix A (Suggestive Appendix)
See 6.1. 2
so Use of sensitivity numbers
The ISO sensitivity numbers of original microfilm can be used in conjunction with a light meter that complies with ISO2720 (see Appendix C). When the light meter is placed flat on an object to measure the illuminance (incident exposure meter), the film's sensitivity numbers are directly used in the exposure meter for light calculations. Try using a gray card with a reflectance of 18% to replace the object being copied, and the ISO sensitivity roller number can be used directly when the exposure meter takes readings from the gray card. In addition, the reflection roller number can also be measured from a matte white surface (reflectance = 90%) or the surface of the same material as the microfilm object. The reading measured in this way will be much higher than the reading measured from the 18% gray card. In this regard, the high reading on the white surface can be compensated by The ISO sensitivity is divided by 5 and rounded to the nearest value on the exposure meter before making exposure calculations. Because the exposure tolerance of original microfilm is quite narrow and the exposure light source is varied, the ISO sensitivity of original microfilm is only used to select the starting point of the test exposure and to compare different films and film processing combinations. To obtain the best image quality of original microfilm, correct exposure is the most critical, and the correct exposure is affected by the characteristics of the object, such as the darkness and width of the line, which cannot be measured with a light meter. Therefore, the exposure combination calculated from the light meter reading cannot be used as the basis for a product exposure before a flash test is conducted.
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