US2343685A - Method of preparing printing surfaces - Google Patents

Description

March 7, 1944. 4 R MacKAY n 2,343,685

METHOD OF PREPARING PRINTING SURFACES Filed Apg. 9, 1941 Flaz.

23 INVEN TOR A706537 MAC KAV BY www,

ATTORNEY -by means of which the preparation Patented Mor. 7, 1944 UNITED STATES' Pai-Terriottici:

' ananas Ma'rnon orsrijtgtgo rmri'rmo Robert MacKay, Cook County, lll., assigner i Alca-Gravure Division of Publication Corporation, New York, N'. Y., a corporation o! New York .The 'present invention relates to ymetl'iods of preparing printing surfaces and embodies, more1 surfaces may be facilitated.

More specifically, this vinvention embodies anl improved method by means of which the size and location of art work may be readily and accurately' established in the preparatory work prior to the etching operation. It is of particular utility in connection with the `preparation of printing surfaces which include aplurality of separate elements which must be located in a certain spaced relation on the print. 'For example, where it is' necessary to include several pieces ci art work in a certain desired spaced relationship, the invention provides a method by means of which the several component parts of the print formed by the several pieces of art work may be accurately positioned and formed of the proper size.

The present method is of particular utility in connection with multi-color printing wherein separate printing elements must be made for each ofthe colors forming component parts of theI print and is also of special importance in connection with operations wherein inserts are to be made Within the outline of a picture or other piece of art work.

Heretoiore the edges of pictures or other art work have been located and trimmed by hand in ,the following manner. Assuming that a color page has live separate pieces of color art to` be assembleciinto a given position and that all ve pieces require cropping or trimming to t the various". positions designated for them on the print, separation negatives are set up in register from a master and positives are made. The edges of the pictures on one of these color positives are scraped by hand to fit the iinlshed layout and,.from'this positive. a photographic image is made on film. This film is positioned over each remaining positive and is used asa guide in trimmingthe plates by hand. y l 4 l l There 'gare 4several objections to the foregoing operation, chief of which is that the hand operation is accomplished with a knife and ruler and is laborious and constantly susceptible to the introduction 'of faults into the product. l A further objection residesin the fact that the iilm used as a guide in scraping' frequently changes size before the work is iinished on all of the plates.

In accordance with the present invention, an improved method is provided by means ofv which the trimming and positioning is accomplished of 'printing photographically and with a high degree of ac- 5 curacy. speciiicaIIy, an improved 'photographic operationl f An object of the present invention, accordingly, is to provide an improved photographic method of preparing printing surfaces by means of which the location and size of individual pieces of art work or component parts of the nal print may be accurately maintained.

A further object of the invention is to provide a method of the above 'character wherein the use of inserts within other -picture or similar areas may be greatly facilitated.

Further objects will be readily apparent as the invention is described in greater detail and to illustrate the invention more fully, reference will be made to the'accompanying drawing, wherein: Fig. l is an illustration of what will be called an originai to be reproduced, together with other' art work, in a print wherein all of the pieces of art work are properly assembled.

Fig. 2 is a diagrammatic illustration of a layout composed offour pieces of art work, assembled in a desired relation, but in which the various pieces are not of correct size.

Fig. 3 is a diagrammatic illustration of a burning or trimming plate utilized in connection with the method of the present invention.

Fig. 4 is an illustration of the art work of Fig. l, in the form of a nal print which will be one of the elements of the composite print.

Referring to the drawing, it is assumed, in the illustration therein given, that the finished print is to consist of four pictures ill, ii, i2 and i3. These pictures are to be arranged in a desired spaced relationship and to be of a predetermined exact size or sizes. Moreover, each of the pictures is assumed to be formed of a plurality l of component colors. Asillustrated in Fig.' l, the picture il includes a design or ligure i4 and to illustrate the various uses to which thefpresent invention can be put, it is to be assumed that cerfv` tain desiredlettersi 5 are to appear on the picture il above the figure i4. These letters may be white, that is-the color of the paper upon which the print is made, -or they may be formed-olfany.A

desired color. It is also assumed that the letter W is to appear in the lower portion of the iiguref` the picture I I.

edges to come as they will, so that the edges of all pictures on all plates extend beyond the size desired in the final print. The assembled positive is then used tb make the carbon print which is to serve as the resist in the operation of etching the printing surface. Such a positive is illustrated at Il in Fig. 2 and, to illustrate what has just been described, the nal or desired edges of the various pictures are illustrated by dotted lines at I9.

In order that the final print may show the various pictures in the proper size and relationship, a wet plate negative is made from the customers layout which is usually drawn in ink and to accurate size. This negative is illustrated at 2l in Fig. 3 and is formed with the exact picture areas in black while all other areas are transparent so that light may pass through The resulting negative is termed a burning or trimming plate because through it, the proper sizes of the pictures are obtained. After the exposure of the positive Il upon thecarbon tissue, the trimming plate 20 is placed in register over the carbon tissue and a second exposure made. This results in light, passing through the transparent areas of the burning plate and hardening the carbon tissue under such areas so that no etching will take place on the copper surface beneath such hardened areas. It will thus be apparent that the edges of the pictures are trimmed photographically to the exact size desired. The result is that all of the various color impressions will occur in perfect register and sharply trimmed to the exact size desired.

To illustrate further'uses of the invention, it will be observed that the burning plate 20 is formed with letters I5 as transparent areas in the desired position so that they will appear over the figure illustrated at I4, in Figs. 1 and 4. These transparent areas on the burning plate will cause the carbon tissue to be hardened and, as a result, will prevent any etching beneath such areas. If no other color is applied in these areas, the result will be that the picture II will -be fcrmed with the white letters I5 appearing sharply therein in the desired position. If a dierent color is to be used for the letters I5, the desired color cylinder or plate will be etched in the areas corresponding to the letters I5 so that the final print will appear with the letters i5 in the desired color.

It is further assumed that the letter W is to not be hardened under this area. The burning plate, within the area of the picture Il, isformed with a transparent area 25 within which the design I1 is received, the design being opaque. As a result, the area 25 on the carbon tissue will be hardened so that no etching will occur beneath it, whereas the areas corresponding to the design I1 will not be hardened and, accordingly, the design will be printed because of the desired etching accomplished beneath such area upon the exposure of the positive upon the carbon tissue.

From the foregoing, it will be apparent that the invention depends essentially upon the use of the `cus'tcimers layout as a means for providlike which are to be superimposed upon or inbe inserted within the figure Il, appearing in This is accomplished .by blacking out the corresponding area at 2| in the positive shown inv Fig. 2. As a result, the gelatin in the carbon tissue beneath the area. 21 will not be hardened. The burning plate 20 is formed with a transparent area 22 within which the letter W appears as opaque. Ihis is illustrated at Il in Fig. 3. When the exposure is made through the burning plate, the transparent area 22 causes the hardening of the unexposed area 2l so that there will be no color applied in that area as illustrated at 2l in Fig. 4. However, the opaque letter W in Fig. 3 prevents the hardening of the carbon tissue leluded within the picture areas and, while it has been described with reference to Y the specific disclosure herein and illustrated in the drawing, it is not to be limited save as defined in the appended claims.

I claim:

1 The method of preparing printing surfaces formed to reproduce desired subject matter in a desired size, comprising preparing a set of transparent photographic color separation prints of the subject matter, preparing a layout of the print, forming a transparent photographic print of the layout in which the area corresponding to the desired subject matter is opaque and of the correct size, exposing each color separation print on a separate carbon tissue and exposing said photographic print of the layout in succession on said carbon tissues whereby the photographic print of the layout will trim the area of the subject matter to the desired size, and preparing a printing surface therefrom in a known fashion.

2. The method of preparing printing surfaces formed to reproduce a plurality of desired subjects in desired sizes and space relationships comprising preparing a set of transparent composite photographic color separation positives containing the subjects infapproximately correct sizes and space relationship, preparing a layout of the finished print, preparing a photographic print of the layout in which the areas corresponding to the desired subjects are opaque and of correct size and the remaining area is transparent, exposing each positive on a separate carbon tissue and exposing said photographic print on said carbon tissues whereby the photographic print will trim the areas of the subjects to 'the desired sizes, and preparing a printing surface therefrom in a known fashion. j

3. The method of preparing printing surfaces formed to reproduce desired subject matter in a desired size and with other subject matter inserted therein, comprising preparing a set of photographic color separation transparencies of the desired subject matter, preparing a layout of the print with the inserted subject matter thereon in the desired position, forming a photographic print of the layout in which the area corresponding to said desiredsubject matter is in the form of a transparency of said inserted subject matter, exposing the color separation transparencies on separate carbon tissues and exposing said photographic print on at least one of said assesses area corresponding to said desired subject matter is opaque except in the areas corresponding to i5 the location of said inserted subject matter and of the correct size and said inserted subject matter is in the form of a positive print, opaquing out areas in said color separation positives that are 'to receive said inserted subject matter, exposing the positives on separate carbon tissues, and reexposing said carbon tissues through said photographie print whereby the photographic print will trim the area of the subject matter to Ithe desired size, and said inserted subject matter will be exposed in the desired areas of said desired subject matter and preparing a printing surface therefrom in a known fashion.

ROBERT MACKAY.

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