This standard specifies the quantitative test method for the smallest details of line images such as digital, text, symbols, graphics, etc. that can be recognized on microfilm. This standard specifies the characteristics of the test pattern and the No. 2 test pattern. This standard is applicable to the determination of the combined resolution (photographic resolution) of the camera, film and processing in the microfilm system, that is, the determination of the resolution of microforms produced by the system. GB/T 6161-1994 Characteristics of the No. 2 test pattern for microfilm technology and its application in microfilm technology GB/T6161-1994 Standard download decompression password: www.bzxz.net
This standard specifies the quantitative test method for the smallest details of line images such as digital, text, symbols, graphics, etc. that can be recognized on microfilm. This standard specifies the characteristics of the test pattern and the No. 2 test pattern. This standard is applicable to the determination of the combined resolution (photographic resolution) of the camera, film and processing in the microfilm system, that is, the determination of the resolution of microforms produced by the system.

National Standard of the People's Republic of China
Micrographics-Test chart No, 2-Deseriplion aneuse in microfilming
GB/T 616↑—94
Replace(i1 6161:85
This standard is equivalent to ISO3334--1989 Microfilm Technology IS02 Resolution Test Chart Instructions and Use 1 Subject Content and Scope of Application
This standard specifies the method for testing the smallest details of recognizable digital, text, symbols, graphics and other line images on microfilm. This standard specifies the characteristics of the test pattern and the No. 2 test chart. During the test, the No. 2 test chart is used as a part of the test target. The composition of the test target should be specified according to the different purposes and requirements of microfilm. This standard is applicable to the determination of the comprehensive resolution of the camera, film and processing in the microfilm system (photographic resolution), that is, the determination of the resolution of microfilms produced by the system. Not applicable to the determination of the resolution of readers, reading copiers or computer output microfilm (CM) imaging systems.
2 Reference standards
GB6159.1 Microfilm Vocabulary Part 1 General terms GB6159.2 Microfilm Vocabulary Part 4 Materials and packaging GB6160 Microfilm technology Silver-gelatin microfilm cavity sheet density GB6987 Microfilm technology Test target for checking negative image optical density during microfilming GB/T12356 Microfilm technology Characteristics and use of test targets for 16mm platform microfilm cameras GB321 Priority numbers and priority number systems
.3 Characteristics of test charts
The test chart consists of a base and a test pattern. 3.1 Base
Base materials are divided into transparent and opaque types. 3.1.1 Transparent substrate
The transparent substrate shall be colorless, and its minimum transmission density value shall not exceed 0.08. The test image can be a positive image or a negative image. 3.1.2 Opaque substrate
The opaque substrate is concave, and its reflection density value shall not be greater than 0.08, or its reflectivity value shall not be less than 85%. The test image is a positive image. 3.2 Test patternbZxz.net
The test pattern consists of two sets of mutually perpendicular parallel lines and marking numbers, see Figure 1. The reflection density value of the test pattern lines of the No. 2 test pattern on the opaque substrate should be above 1.60, and the difference in reflective density between the line interval and the substrate should not be greater than 0.02. The density difference between the test pattern lines and the base of the test pattern on the transparent base should not be less than 3. The test pattern lines and intervals should comply with the provisions of Appendix A. The width of the lines and intervals should be measured using a calibrated precision microscope with a micrometer, a sheet-powered tool microscope, an optical comparator or a computer-controlled coordinate measuring device. The measured values ​​should be consistent with the values ​​listed in Table 1, and the measurement accuracy should be less than 1μn. Table 1 Test pattern size and tolerance
Test pattern spatial frequency
(line pair/meter)
Interval frequency tolerance
Range of line length
Value range of spacing
3.3 Spatial frequency of the test pattern
Within ±3 of its nominal value
22. 8~25. 2
1-~10 line pair/meter 0.95~1.05
11~18 line pair/mm 0.901. 10
If the spatial frequency of the test pattern is F and the line pair width is $, then F: 1
The spatial frequency of the test pattern No. 2 starts from 1.0 and is arranged in the R20 series numerical hierarchy specified in GB321. Except for the 1.25 and 12.5 two-level patterns, the average increment of the adjacent two-level spatial frequency of other patterns is 12.2%, as shown in Figure 1. Line pair width S
Line width number
Line interval width number
Digital quantity width 10.S
Test sample
GB/T 6161—94
Before checking the size tolerance of the test pattern, the test pattern should be placed in an environment with a temperature of 23±2℃ and a relative humidity of 50%±5% for at least 3. 4 Digital marking of test patterns, method
The digital number marked on the test pattern represents the spatial frequency of the group of patterns, that is, the number of line pairs, lines and intervals contained per millimeter. For example: the number marked on the test pattern is 2.0, which means the line width is 0.25mm, and the line pair width consisting of a line and a line space is 0.50mm. The spatial frequency of the pattern is 2 line pairs per millimeter, that is, 2 line pairs/mm. 3.5 Test pattern number
The number marked on the test pattern should be placed in the upper right corner of the rectangular pattern, see Figure 1, and the font of the number should be Gothic or other fonts suitable for microfilming.
3.6 Arrangement of test patterns
Test patterns are arranged in the order of increasing spatial frequency: see Figure 2. 1.0
Figure 22 Resolution Test Pattern
3.7 Test Pattern Name and Source
Below the test pattern should be marked "Resolution Test Pattern No. 2\ and its supervisory or issuing agency. 4 Application of test patterns
4.1 According to the relevant national standards, the test pattern is photographed on film by a camera to make a microfilm. 4.2 Reading of test pattern images
4.2.1 Microscope
The microscope should have a commercial quality achromatic objective. The total magnification of the microscope should be the minimum test pattern to be observed. The imaging power is 1/3 to 1 times of the number of line pairs per millimeter. For example, if you want to observe that the minimum test pattern has a comprehensive resolution of 150 line pairs/mm, the magnification of the microscope should be between 50 times and 150 times.
4.2.2 Detection of test patterns
When checking the test pattern with a microscope, if the lines in two directions on a test pattern can be clearly distinguished, the pattern is considered to be resolvable, and the spatial frequency of the minimum resolvable pattern is read accordingly. For example: The spatial frequency of the minimum resolvable pattern in Figure 3 is 5.6. 4.2.3 Pseudo-resolution phenomenon
Sometimes, although the base-image cannot be distinguished, four-fifths of the lines of the smaller pattern can be distinguished, that is, pseudo-resolution phenomenon occurs. At this time, the real resolution The imaging value should be calculated using the spatial frequency of a pattern that is one level larger than the indistinguishable pattern. 4.2.4 Lines in four directions are indistinguishable
If a group of lines in the same direction in the test pattern can be distinguished, but another group of lines perpendicular to it cannot be distinguished, it may be caused by the astigmatism of the inspector. To verify this phenomenon, the pattern needs to be rotated 90 degrees and observed again. If the group of lines is still indistinguishable, it must be caused by defects in the microfilm or microfilm. 4.2.5 Comprehensive
GR/T6161-94
In order to express the comprehensive resolution value of the camera, film and development processing conditions in terms of the number of line pairs per linear metre, the spatial frequency of the smallest resolvable pattern should be multiplied by the reduction ratio when shooting. It is expressed as the reciprocal of. For example: the spatial frequency of the smallest resolvable pattern is 5.0, the reduction ratio is 1/24, and the comprehensive resolution value is 120 line pairs/mm. 2.8
Figure 3 Test pattern shot on film (enlarged copy) Figure 3 is a test pattern shot on film (enlarged copy). The 5.6 pattern is considered to be the smallest resolvable pattern. GE/6161—94
Appendix A
(Supplement)
When making test chart No. 2, defects may appear in its lines or spaces. The size of the defect relative to the size of the line or space determines the degree of its influence on the comprehensive resolution test result. Recommendation: Test chart No. 2 with one of the following defects cannot be used.
The edge of the line is not vertical at the angle, and the edge of the line is defective or uneven. b.
There are empty areas or spots on the lines or intervals, and their size exceeds half of the width of the lines or intervals. c.
The damage, breakage or spots on the lines or intervals completely pass through or exceed half of the width of the lines or intervals. d. The breakage or spots along the long side of the lines or intervals are longer than one-quarter of the length of the lines or intervals. Figure A1 shows the main defects in test chart No. 2 that make it unusable.
Additional notes:
Test chart defect chart
This standard was proposed by the National Microfilm Photography Technical Standardization Technical Committee. This standard was drafted by the Fourth Subcommittee of the Jinguo Microfilm Technology Standardization Technical Committee (Quality Standard Subcommittee). The main drafter of this standard is Qin Zhaoying,Zhang Zhanhui, He Guangti, Liu Fengzhi
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