1、 Reference number ISO 446:2004(E) ISO 2004INTERNATIONAL STANDARD ISO 446 Third edition 2004-03-15 Micrographics ISO character and ISO test chart No. 1 Description and use Micrographie Caractre ISO et mire ISO N 1 Description et utliisation ISO 446:2004(E) PDF disclaimer This PDF file may contain emb
2、edded typefaces. In accordance with Adobes licensing policy, this file may be printed or viewed but shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In downloading this file, parties accept therein the responsibility of
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4、 were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below. ISO 2004 All rights reserved. Unless otherwise spe
5、cified, 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 in the country of the requester. ISO copyright office
6、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 2004 All rights reservedISO 446:2004(E) ISO 2004 All rights reserved iiiContents Page Foreword iv Introduction v 1 Scope 1 2 Normative references. 1
7、3 Terms and definitions. 1 4 Description and use of the ISO character 2 4.1 Description 2 4.2 Use 2 5 Production of ISO test chart No. 1 2 5.1 Base 2 5.2 Test chart lay-out 4 5.3 Density-measuring areas. 6 5.4 Identification 6 5.5 Certification of ISO No. 1 test charts 7 6 Procedure for using ISO te
8、st chart No. 1 7 6.1 Method 7 6.2 Density of the film . 7 6.3 Legibility control. 7 ISO 446:2004(E) iv ISO 2004 All rights reservedForeword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing Inter
9、national 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 committee. International organizations, governmental and non-governmental, in liaison wit
10、h 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 accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technica
11、l 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 requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to
12、 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 446 was prepared by Technical Committee ISO/TC 171, Document management applications, Subcommittee SC 1, Quality. This
13、 third edition cancels and replaces the second edition (ISO 446:1991), which has been technically revised. ISO 446:2004(E) ISO 2004 All rights reserved vIntroduction Most processes produce images of lower quality; among others diffusion transfer, if it still exists, is capable of enhancing quality.
14、This degradation may go so far as to make the information illegible. Poor legibility may also cause visual fatigue after prolonged viewing. The legibility of an image can be assessed by measuring the limit of resolution, i.e. the ability to distinguish lines in different directions. However, the lim
15、it of resolution corresponds to a quality level insufficient to permit easy reading, and to prolong it without visual fatigue. A criterion which better simulates actual working conditions was sought. The ISO character, which is a conventional character similar to typefaces used in the printing indus
16、try, the outline and details of which should be distinguished without difficulty, meets these requirements. The main practical applications of the ISO character are based on the following experimental properties. a) If a particular reproduction process gives an identifiable image from a group of ISO
17、 characters of a certain height, it can be assumed that the same process will produce, from a printed text of comparable typeface size, a satisfactory image and, in particular, one that is sharp enough to be read, without undue visual fatigue for the viewer. b) In general, the identification of the
18、same limiting group of ISO characters by different observers gives substantially identical results. Care should be taken when referencing this International Standard in other standards. Some countries do not use this standard or use alternative standards (such as ISO 3334:1989, Micrographics ISO res
19、olution test chart No. 2 Description and use). INTERNATIONAL STANDARD ISO 446:2004(E) ISO 2004 All rights reserved 1Micrographics ISO character and ISO test chart No. 1 Description and use 1 Scope This International Standard specifies the characteristics of the black and white ISO character and of t
20、he ISO test chart No. 1, as well as their use. It applies to the quality control of the microimages produced with a given micrographic system and the assessment of the potential legibility of the documents recorded using that system. 2 Normative references The following referenced documents are indi
21、spensable 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 3:1973, Preferred numbers Series of preferred numbers ISO 5-2:2001, Photography Density
22、measurements Part 2: Geometric conditions for transmission density ISO 5-3:1995, Photography Density measurements Part 3: Spectral conditions ISO 5-4:1995, Photography Density measurements Part 4: Geometric conditions for reflection density ISO 2471:1998, Paper and board Determination of opacity (pa
23、per backing) Diffuse reflectance method ISO 6196-1:1993, Micrographics Vocabulary Part 1: General terms 180 6196-2:1993, Micrographics Vocabulary Part 2: Image positions and methods of recording ISO 6196-3:1997, Micrographics Vocabulary Part 3: Film processing ISO 6196-4:1998, Micrographics Vocabula
24、ry Part 4: Materials and packaging ISO 6196-5:1987, Micrographics Vocabulary Part 5: Quality of images, legibility, inspection ISO 6196-6:1992, Micrographics Vocabulary Part 6: Equipment ISO 6200:1999, Micrographics First generation silver-gelatin microforms of source documents Density specification
25、s and method of measurement 3 Terms and definitions For the purposes of this document, the terms and definitions given in ISO 6196 apply. ISO 446:2004(E) 2 ISO 2004 All rights reserved4 Description and use of the ISO character 4.1 Description The ISO character is a conventional character, similar to
26、 printing typefaces, the shape and size of which is specified below. It consists of a regular octagon, of a given height c, with two internal parallel lines, the width of lines and spaces being c/7 (see Figure 1). The tolerances of c are specified in 5.2.2. Figure 1 Enlarged drawing of the ISO conve
27、ntional character for legibility test The internal lines may be oriented in four different ways: vertically, horizontally, 45 to the right, and 45 to the left. This orientation is defined by one of the following terms: Vertical Horizontal Right-inclined Left-inclined 4.2 Use The ISO character may be
28、 used in micrographics for making black and white or colour test charts for the quality control of microform production equipment, or microtest charts for use with viewing and printing equipment. It may also be used for controlling the quality of images produced with other techniques (photography, r
29、eprography, etc.). 5 Production of ISO test chart No. 1 5.1 Base The test chart shall be made on either an opaque or a transparent base. ISO 446:2004(E) ISO 2004 All rights reserved 35.1.1 Opaque base The test chart shall be made on a white opaque base (preferably glossy). Its visual diffuse reflect
30、ion density, measured in accordance with ISO 5-3 and ISO 5-4, shall be not more than 0,08. Its opacity, measured as specified in ISO 2471, shall be greater than 85 %. This test chart shall be positive-appearing. 5.1.2 Transparent base The test chart shall be made on a non-coloured transparent base h
31、aving a maximum visual diffuse transmission density, base + fog, of 0,08 measured in accordance with ISO 5-2 and ISO 5-3. This test chart may be positive-appearing or negative-appearing. ISO 446:2004(E) 4 ISO 2004 All rights reserved5.2 Test chart lay-out ISO test chart No. 1 consists of groups of I
32、SO characters arranged as shown in Figure 2. NOTE The numbers shown in this figure are the values given in 5.2.2 divided by 10 m. This illustration is not to be used for testing. Figure 2 Sample layout of ISO test chart No. 1 ISO 446:2004(E) ISO 2004 All rights reserved 55.2.1 Group of characters Ea
33、ch group comprises four ISO characters of the same size, each of different orientation (see 4.1). The characters shall be arranged in a square pattern as shown in Figure 3 and shall be oriented randomly. The minimum space between two characters, horizontally and vertically, shall be 2c/7. The minimu
34、m space between two groups of characters shall be 2c/7 of the smallest character of the two groups. Figure 3 Examples of groups of ISO characters 5.2.2 Sizes of characters Dimension c, in micrometres, of the four characters of each group shall be established by reference to the R 20 series of prefer
35、red numbers specified in ISO 3: 450 500 560 630 710 800 900 1000 1120 1250 1400 1600 1800 2000 2250 2500 2800 The white and black lines within each group of four characters shall have the same widths, with a tolerance of 7 m, measured on each character segment (see Figure 4). However, the maximum to
36、lerance on these dimensions (c/7) shall be 2 %. 5.2.3 Contrast The minimum visual diffuse density difference between the base and the characters shall be 3,0 for test charts on a film base and 1,6 for test charts on paper. ISO 446:2004(E) 6 ISO 2004 All rights reservedFigure 4 Measurement of line wi
37、dth The visual diffuse density of the white lines in the ISO character should be not more than 0,02 greater than the visual diffuse density of the paper. 5.2.4 Identification of the groups of characters Each group is identified by a number, placed at the bottom of the group, corresponding to the siz
38、e of the characters it contains. For example, number 45 corresponds to a group composed of characters with dimension c of 0,45 mm in size. The numbers shall be legible to the naked eye. The size of the numbers corresponding to characters smaller than 125 shall be greater than those of the correspond
39、ing characters. 5.3 Density-measuring areas To check that the test chart meets the requirements of 5.2.3, it shall include two areas, a clear one for measuring the background density of the test chart, and a dark one, the density of which shall be considered to be equal to that of the characters. Ea
40、ch area shall be at least 10 mm 10 mm. These areas are identified as A and B in Figure 2. NOTE These areas are not used for measuring the densities of the microimages (see 6.2). 5.4 Identification The words “ISO test chart No. 1“, a reference to this International Standard or to any equivalent natio
41、nal standards and the certifying agent 1), or source of issue shall appear on the test chart. 1) Test charts certified to conform to this International Standard can be obtained from AFNOR, 11, avenue Francis-de- Pressens, F-93571 Saint-Denis La Plaine Cedex, France. Tel: +33 (0)1 41 62 80 00. Fax: +
42、33 (0)1 49 17 90 00. Web site: http:/www.afnor.fr ISO 446:2004(E) ISO 2004 All rights reserved 75.5 Certification of ISO No. 1 test charts Only test charts complying in every respect with this International Standard and verified by a qualified laboratory can be designated as ISO No. 1 test charts. 6
43、 Procedure for using ISO test chart No. 1 6.1 Method Position ISO test charts within the microfilming area so as to test the whole field of view. As a minimum, this shall be in the centre and the four corners. Make test exposures using the same film and processing conditions as will be used in produ
44、ction. 6.2 Density of the film Measure the background visual diffuse transmission density of the microimages of the test chart in accordance with ISO 6200. When positive-appearing test charts are used, this density shall be 1,60 0,10. 6.3 Legibility control Examine the microimages of the ISO test ch
45、art No. 1 with a microscope of magnification 30 to 50, fitted with a lens having a numerical aperture of at least 0,1. A group of ISO characters of a given size considered in any area of the microimage shall be regarded as “read” if, within each character, all black and white lines are discernible a
46、nd without discontinuity. Figure 5 gives examples of characters “read” and “nonread”. The minimum sizes of the characters which are “read” vary in relation to the reduction ratios used. READ NONREAD Figure 5 Examples of characters “read” and “nonread” ISO 446:2004(E) ICS 37.080 Price based on 7 pages ISO 2004 All rights reserved
