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1、BRITISH STANDARD BS 3649:1963 Recommendations for Original printing plates Licensed Copy: sheffieldun sheffieldun, na, Wed Nov 29 05:40:39 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 3649:1963 This British Standard, having been approved by the Printing, Stationery and Allied Trades Standards Commi
2、ttee, was published under the authority of the General Council on 9 August 1963 BSI 02-2000 The following BSI references relate to the work on this standard: Committee reference S/25 Draft for comment D62/9984 ISBN 0 580 34405 3 Co-operating organizations The Printing, Stationery and Allied Trades S
3、tandards Committee, under whose supervision this British Standard was prepared, consists of representatives from the following government department and scientific and industrial organizations: Association of British Manufacturers of Printers Machinery* British Federation of Master Printers* British
4、 Paper & Board Makers Association (Incorporated) Business Equipment Trade Association Electrotyping & Stereotyping Employers Federation* Envelope Makers & Manufacturing Stationers Association Federation of Master Process Engravers* H.M. Stationery Office* National Association of Paper Merchants News
5、paper Society* Periodical Proprietors Association Ltd.* Printing, Packaging & Allied Trades Research Association* Society of British Printing Ink Manufacturers Stationers Association of Great Britain & Ireland The organizations marked with an asterisk in the above list, together with the following,
6、were directly represented on the Committee entrusted with the preparation of this British Standard: Advertisement Production Employers Federation Association of Manufacturers and Suppliers for the Graphic Arts Incorporated Society of British Advertisers Institute of Practitioners in Advertising Lond
7、on College of Printing London Typographical Society National Society of Electrotypers & Stereotypers Newspaper Proprietors Association Society of Lithographic Artists, Designers, Engravers & Process Workers Typographical Association Amendments issued since publication Amd. No.DateComments Licensed C
8、opy: sheffieldun sheffieldun, na, Wed Nov 29 05:40:39 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 3649:1963 BSI 02-2000i Contents Page Co-operating organizationsInside front cover Forewordii 1Scope1 2Materials1 3Depth of etch (line)1 4Depth of etch (half-tone)1 5Method of depth measurement1 6Quali
9、ty of etch1 7Finishing1 Appendix A Notes on the use of half-tone and line printing plates2 Figure 1 Correctly formed profile2 Figure 2 Pin point highlights2 Figure 3 Insufficient depth2 Figure 4 Over etched2 Figure 5 False depth2 Figure 6 Underbiting2 Figure 7 Pitted dots2 Figure 8 Bridges connectin
10、g dots2 Table 1 Recommended minimum depths of etch1 Licensed Copy: sheffieldun sheffieldun, na, Wed Nov 29 05:40:39 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 3649:1963 ii BSI 02-2000 Foreword This standard makes reference to the following British Standard: BS 1705, Sizes of metal sheets for lett
11、erpress photo-engravings. At a conference on newspaper and rotary letterpress work called by the Printing, Packaging and Allied Trades Research Association, there was a strong feeling that the issue and adoption of a British Standard Recommendation could help to overcome such faults as shallow half-
12、tones, thickness variations across plate and insufficient routing. Accordingly the Printing, Stationery and Allied Trades Standards Committee authorized the preparation of this recommendation at the request of the Printing, Packaging and Allied Trades Research Association. The Committee responsible
13、for preparing the recommendation have recognized that results which seem to arise from such faults may in fact be caused by other factors in the printing process. However, it is hoped that general use of this recommendation will be of considerable value to platemakers, printers and other purchasers
14、of plates. NOTEWhere metric equivalents are stated the figures in British units are to be regarded as the standard. The metric conversions are approximate. More accurate conversions should be based on the tables in BS 350, “Conversion factors and tables”. A British Standard does not purport to inclu
15、de all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages
16、i and ii, pages 1 and 2 and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover. Licensed Copy: sheffieldun sheffieldun, na, Wed Nov 29 05:40:39 GMT+00:00 2006, Uncontrolle
17、d Copy, (c) BSI BS 3649:1963 BSI 02-20001 1 Scope These recommendations deal with the depth of etch for haft-tone and line printing plates used for direct flat-bed printing or duplication. Appendix A gives guidance on the use of these plates. 2 Materials Plates should be made from sheets complying w
18、ith the dimensional requirements of BS 1705, “Sizes of metal sheets for letterpress photo-engravings”. The type of material should be agreed between customer and engraver. 3 Depth of etch (line) Line plates for subsequent duplication and use in newspaper rotary printing should be etched to a depth o
19、f 0.028 in (0.711 mm). Line plates for direct letterpress should be etched to a depth of 0.022 in (0.559 mm). Line plates for rubber stereos should be etched to a depth as agreed between engraver and the customer, and may well vary considerably in accordance with the purpose for which the rubber pla
20、te is to be used. The above-mentioned depths may reasonably be expected to vary by plus or minus 0.001 in (0.025 mm). All readings should be taken in the open etched areas, not less than 1/4 in (6.3 mm) from the printing area. 4 Depth of etch (half-tone) Half-tone plates should be etched to a depth
21、not less than that given for the appropriate number of screen lines per linear inch given in Table 1. Recommendations for future developments in plate-making should be considered on their individual merits and as they arise. 5 Method of depth measurement A depth measuring microscope is the only reli
22、able instrument for the accurate measurement of the depth of etch. A depth measuring microscope with a maximum dial reading of 0.015 in (0.381 mm) is recommended for half-tones. For the measuring of line plates, a needle type depth gauge is considered adequate. NOTEIn general, an 8 mm objective will
23、 give a suitable depth of focus and the field of view and working distance will be adequate for depth measurements on all half-tone plates. For coarse screen plates the larger field of a 16 mm objective may be preferable and for measurements on the finest screens a 4 mm objective would permit greate
24、r accuracy. 6 Quality of etch The profile of the relief, whether line or dot, should be clearly etched and be similar to that shown in Figure 1. All other profiles, as illustrated in Figure 2 Figure 8 shall be avoided. 7 Finishing Physical corrections of tone values by burnishing should be avoided.
25、The routing of plates to obtain greater depth to ensure clean printing is an accepted practice. The degree of “skeletonizing” (excessive removal of non-printing metal) is a matter for agreement between the purchaser and the photo-engraver, and should take account of the need to minimize the risk of
26、distortion during, transport and use. Table 1 Recommended minimum depths of etch Screen lines per liner inch Highlight 10 per centMidtone 50 per centShadow 90 per cent 0.001 inmm0.001 inmm0.001 inmm 50 55 60 65 75 85 100 120 133 150 6 51/2 51/4 43/4 41/4 31/2 3 21/2 21/4 2 0.152 0.140 0.133 0.121 0.
27、108 0.089 0.076 0.063 0.057 0.051 43/4 41/4 4 31/2 3 21/2 2 11/2 11/2 1 0.121 0.108 0.102 0.089 0.076 0.063 0.051 0.038 0.038 0.025 33/4 3 21/2 21/4 13/4 11/2 11/2 11/4 1 3/4 0.095 0.076 0.063 0.057 0.044 0.038 0.038 0.032 0.025 0.019 Licensed Copy: sheffieldun sheffieldun, na, Wed Nov 29 05:40:39 G
28、MT+00:00 2006, Uncontrolled Copy, (c) BSI BS 3649:1963 2 BSI 02-2000 Appendix A Notes on the use of half-tone and line printing plates Whatever the quality of plate it will not print satisfactorily unless the paper used for printing has been taken into account when the screen ruling is selected. In
29、general, coated papers are less likely to result in the filling-up of etched areas on half-tone plates than are uncoated papers. Frequently the complaint that the block is shallow is incorrect. The fault may result from the screen selected being too fine for the paper being used, or the ink being to
30、o thin. Either or both of these conditions would produce a similar result to that caused by lack of printing depth. Experiments have shown that there is a loss of depth in the moulding process, especially in newspaper printing. In certain circumstances this may be critical and allowance may have to
31、be made for the quality and treatment of the flong. Figure 1 Correctly formed profile Figure 2 Pin point highlights Will probably collapse under pressure Figure 3 Insufficient depth Possible “filling-in” especially after moulding Figure 4 Over etched Tops of dots below printing surface Figure 5 Fals
32、e depth Effective printing depth less than measured depth Figure 6 Underbiting Will prevent removal of matrix. Dots will be damaged Figure 7 Pitted dots Reduction in printing area. Loss in density Figure 8 Bridges connecting dots Could print up during printing run Licensed Copy: sheffieldun sheffiel
33、dun, na, Wed Nov 29 05:40:39 GMT+00:00 2006, Uncontrolled Copy, (c) BSI blank Licensed Copy: sheffieldun sheffieldun, na, Wed Nov 29 05:40:39 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 3649:1963 BSI 389 Chiswick High Road London W4 4AL BSI British Standards Institution BSI is the independent nati
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