1、BRITISH STANDARD BS 3649:1963 Recommendations for Original printing platesBS3649:1963 This British Standard, having been approved by the Printing,Stationery and AlliedTrades Standards Committee, was published underthe authority of the GeneralCouncil on 9August1963 BSI 02-2000 The following BSI refer
2、ences 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 Standards Committee, under whose supervision this British Standard was prepared, consists of representatives from th
3、e following government department and scientific and industrial organizations: Association of British Manufacturers of Printers Machinery* British Federation of Master Printers* British Paper & Board Makers Association (Incorporated) Business Equipment Trade Association Electrotyping & Stereotyping
4、Employers Federation* Envelope Makers & Manufacturing Stationers Association Federation of Master Process Engravers* H.M. Stationery Office* National Association of Paper Merchants Newspaper Society* Periodical Proprietors Association Ltd.* Printing, Packaging & Allied Trades Research Association* S
5、ociety 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, were directly represented on the Committee entrusted with the preparation of this British Standard: Advertisement P
6、roduction Employers Federation Association of Manufacturers and Suppliers for the Graphic Arts Incorporated Society of British Advertisers Institute of Practitioners in Advertising London College of Printing London Typographical Society National Society of Electrotypers & Stereotypers Newspaper Prop
7、rietors Association Society of Lithographic Artists, Designers, Engravers & Process Workers Typographical Association Amendments issued since publication Amd. No. Date CommentsBS3649:1963 BSI 02-2000 i Contents Page Co-operating organizations Inside front cover Foreword ii 1 Scope 1 2 Materials 1 3
8、Depth of etch (line) 1 4 Depth of etch (half-tone) 1 5 Method of depth measurement 1 6 Quality of etch 1 7 Finishing 1 Appendix A Notes on the use of half-tone and line printing plates 2 Figure 1 Correctly formed profile 2 Figure 2 Pin point highlights 2 Figure 3 Insufficient depth 2 Figure 4 Over e
9、tched 2 Figure 5 False depth 2 Figure 6 Underbiting 2 Figure 7 Pitted dots 2 Figure 8 Bridges connecting dots 2 Table 1 Recommended minimum depths of etch 1BS3649:1963 ii BSI 02-2000 Foreword This standard makes reference to the following British Standard: BS 1705, Sizes of metal sheets for letterpr
10、ess 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-tone
11、s, 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 for
12、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 of p
13、lates. 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 BS350, “Conversion factors and tables”. A British Standard does not purport to include al
14、l 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 i and
15、 ii, pages1 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.BS3649:1963 BSI 02-2000 1 1 Scope These recommendations deal with the depth of etch for haft-tone
16、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 with the dimensional requirements of BS1705, “Sizes of metal sheets for letterpress photo-engravings”. The type of
17、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 of0.028 in (0.711mm). Line plates for direct letterpress should be etched to a depth of0.022 in (0.559mm). Line plat
18、es 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 plate is to be used. The above-mentioned depths may reasonably be expected to vary by plus or minus0.001 in (0.025mm). All
19、 readings should be taken in the open etched areas, not less than 1 / 4in (6.3mm) from the printing area. 4 Depth of etch (half-tone) Half-tone plates should be etched to a depth not less than that given for the appropriate number of screen lines per linear inch given inTable 1. Recommendations for
20、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 reliable instrument for the accurate measurement of the depth of etch. A depth measuring microscope with a maximum dial readin
21、g of0.015 in (0.381mm) is recommended for half-tones. For the measuring of line plates, a needle type depth gauge is considered adequate. NOTEIn general, an8mm objective will give a suitable depth of focus and the field of view and working distance will be adequate for depth measurements on all half
22、-tone plates. For coarse screen plates the larger field of a16mm objective may be preferable and for measurements on the finest screens a4mm objective would permit greater accuracy. 6 Quality of etch The profile of the relief, whether line or dot, should be clearly etched and be similar to that show
23、n inFigure 1. All other profiles, as illustrated inFigure 2 Figure 8 shall be avoided. 7 Finishing Physical corrections of tone values by burnishing should be avoided. The routing of plates to obtain greater depth to ensure clean printing is an accepted practice. The degree of “skeletonizing” (exces
24、sive 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 distortion during, transport and use. Table 1 Recommended minimum depths of etch Screen lines per liner inch Highlight 10 per cent M
25、idtone 50 per cent Shadow 90 per cent 0.001 in mm 0.001 in mm 0.001 in mm 50 55 60 65 75 85 100 120 133 150 6 5 1 / 2 5 1 / 4 4 3 / 4 4 1 / 4 3 1 / 2 3 2 1 / 2 2 1 / 4 2 0.152 0.140 0.133 0.121 0.108 0.089 0.076 0.063 0.057 0.051 4 3 / 4 4 1 / 4 4 3 1 / 2 3 2 1 / 2 2 1 1 / 2 1 1 / 2 1 0.121 0.108 0.
26、102 0.089 0.076 0.063 0.051 0.038 0.038 0.025 3 3 / 4 3 2 1 / 2 2 1 / 4 1 3 / 4 1 1 / 2 1 1 / 2 1 1 / 4 1 3 / 4 0.095 0.076 0.063 0.057 0.044 0.038 0.038 0.032 0.025 0.019BS3649:1963 2 BSI 02-2000 Appendix A Notes on the use of half-tone and line printing plates Whatever the quality of plate it will
27、 not print satisfactorily unless the paper used for printing has been taken into account when the screen ruling is selected. In 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
28、shallow is incorrect. The fault may result from the screen selected being too fine for the paper being used, or the ink being too 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
29、the moulding process, especially in newspaper printing. In certain circumstances this may be critical and allowance may have to 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 Insuffici
30、ent depth Possible “filling-in” especially after moulding Figure 4 Over etched Tops of dots below printing surface Figure 5 False 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 printi
31、ng area. Loss in density Figure 8 Bridges connecting dots Could print up during printing runblankBS 3649:1963 BSI 389 Chiswick High Road London W4 4AL BSIBritishStandardsInstitution BSI is the independent national body responsible for preparing BritishStandards. It presents the UK view on standards
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