US2168444A - Process of producing printing plates - Google Patents

Description

Aug. 8, 1939. E. D. LAKE 2,168,444

PROCESS OF PRQDUCING PRINTING PLATES 7 Filed May 25, 1936 Patented Aug. 8, 1939 OFFICE PROCESS OF PRODUCING PRINTING PLATES Elsinore D. Lake, Oakland, Calif. Application May 25, 1936, Serial No. 81,620

. 2 Claims.

This invention relates to the production of plates used in multi-color printing, and is an improvement over the invention disclosed in my prior application, Serial No. 45,074, filed October 15, 1935 now Patent No. 2,129,945, September 13, 1938. In the above identified prior application, a process is set forth by means of which plates, for producing prints made up of distinct component areas, each of a different color, may be made entirely photo-mechanically without the necessity of manual color separating on negative or plate of any nature, and which will produce prints in which the edges'of component color areas are in perfect registry.

The principal object of the present invention is to provide a process which, unlike the one described above, will produce printing plates for deliberately overlapping the edges of component areas of the print to whatever extent desired so as to provide for covering areas of the paper between color areas which might otherwise be left uncovered due to imperfect registry. I

The invention possesses other objects'and features of advantage; some of which, together with the foregoing, will be specifically. set forth in the detailed description of the invention hereunto annexed. It is to be understood that the process is not to be limited to the specific procedure herein described as other modes of securing the desired result may be employed within the scope of the appended claims.

In the drawing in which all of the views are top plan views:

Figure 1 is the master drawing.

Figure 2, is the modified master drawing from which the printing plates are photographically produced.

Figures 3, 4, and 5 are the plates, for printing the component areas of the desired print.

Figure 6 is a print made with the plates shown in Figures 3, 4 and 5.

In my prior application, to produce the printing plates necessary to reproduce a print having a number of component areas of difierent color, a master drawing 1 was made identical with the print to be reproduced except that that areas instead of being colored as they appear in the finished print, are coated with primary colors, for instance, the outer border 8 is colored red, the field 9 is colored yellow, and the lettering or third area Ill is colored blue. The master drawing is then set upbefore a camera and exposures are made therefrom on separate plates or film,

, through filters which will separate each color from the other thereby resulting in the production of a negative for each of the component areas of the drawing from which the printing plates are then made.

Suppose that, in addition to the three separate 5 areas shown in Figure 1, it is desired to place a border about the field 9 or outline'the letter ID. This would create a fourth area which would require an additional printing plate. w

In some processes, such as rotogravure printing 10 and certain box and label letter press printing, .itisdesirable to have component areas of color overlap. Such procedure will overcome the possibility of imprinted areas appearing between multi-colored prints due to faulty registry. This 15 procedure may also be used to combine colors to produce another color.

In my improved process areas of the print may be bordered and letters and figures may be outlined without the need of an additional printing :0 plate to produce them.

In practicing my improved method a master drawing I, produced in primary colors, is made ofthe. desired print. On this master drawingthe area ll occupied by the desired border is blackened, this area being shown, in Figure 2, as overlying a portion of the border 8 and contacting the edge of the field 9.

The master drawing thus modified is placed before a camera and an exposure is made through a color filter which will record on the film or plate only the image of the border 8 and the black area II. The printing plate l2 which is produced from this negative andcontains'the area l3 definingthe areas 8 and II of the master drawing, is shown in Figure 3.

Another exposure of the master drawing is now made through a color filter which will record only the areas 9 and II exclusive of the areas 8 and Ill. The printing plate l4 containing the 40 area l5 which defines the areas 9 and H is shown in Figure 4.

In photographing the master drawing to make a negative of the area l0 it may be desirable, in some instances; to include the area H which being black, will photograph equally as well as the desired area regardless of the color filter used.v In other instances it may be desirable to exclude the area I I which may be done by placing a mask of a color which will be excluded from the photographic image over the area II when the exposure is made. The printing plate l6 bearing the area ll which defines the area ID of the master drawing is shown in Figure 5.

The severalprinting plates may now be set up i in the press and inked to produce a print having any combination of colors. Such a print is shown in Figure 6 wherein the first area printed is the letter I! produced ,by the plate It and colored black, the second area. printed being the field ll, colored blue and produced by. the plate I4, and the final area printed being the border 20, colored yellow, and produced by the plate l2. It will be observed that the impression of the plate I: has inner, dimensions Ad, and the impression of the plate ll has outer dimensions Bb. These correspond respectively with the dimensions Cc and Dd oi the master drawing and on the finished print produce an overlap which provides a border 2| about the field I! which, due to the superposition of the blue and yellow colors of the field and border respectively, prevents the exposure of unprinted paper between the color areas, due to faulty registry.

As was stated above, if in producing the plate ii the area I I is allowed to photograph togetherwith the area I! the finished print will have an additional color, corresponding to the color of the letter "superposed on the border 2i which will change the border from a blend of the colors of the border and field ll to a distinctly diil'erthat decorative borders or outlines may be produced by use of the printing plates which apply the inks to the other component areas of the print and that no additional plate for the production 01' such borders or outlines is required.

I claim:

1. The method of multicolor printing to reproduce an original image comprising a plurality of distinct differently-colored component field areas and an area of another color bordering one of said field areas, which consists in preparing a single master drawing of said image and, in doing so, forming the field areas of the drawing in primary colors irrespective of the colors in the original and forming the border in black, photographing the master drawing through each of a set of color filters separately and in succession to produce a plurality of separation negatives, said set having the same number of filters as there are field areas in the drawing, and each of said filters being selected to record said border and only one of said field areas, photographically reproducing each negative upon a separate printing plate, etching the plates, and printing in superimposition each plate with an ink corresponding in color to that of the field area of the original image which such plate represents.

2. The method of multicolor printing to reproduce an original image comprising a plurality of distinct differently-colored component field areas and an area of another color bordering one of said field areas, which consists in preparing a single master drawing of said image and, in doing so, forming the field areas of the drawing in primary colors irrespective of the colors in the original and forming the border in black, photographing the master drawing through each, except one, of a set or color filters separately and in succession to produce a plurality of separation negatives, said set having the same number of filters, less the aforementioned one, as there are field areas in the drawing and each of said filters being selected to record said border and only one of said field areas, masking said border so as to render it unrecordable photographically, photographing said master drawing including said masked border area through the excepted one of said filters so as to produce a separation negative containing a photographic record only of one field area of the drawing, photographically reproducing each negative upon a separate printing plate, etching the plates, and printing in superimposition each plate with an ink corresponding to that of the field area of the original image which such plate represents.

ELSMORE D. LAKE.

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