DE538342C - Process for the production of master copies for printing plates - Google Patents

Description

GERMAN EMPIRE

ISSUED ON NOVEMBER 13, 1931

REICH PATENT OFFICE

PATENT LETTERING

538 CLASS 57d GROUP

Wolfsohn G.m.b.H. in Berlin

To get a picture like a Photographic ο. Like. To transfer to a printing plate, it was hitherto, necessary, in laborious work, the effects of light and shadow present on the picture by applying differently dense dot, line or pattern grids in the tangier process for production to make the printing cliché suitable. Because of this great amount of working time the price of such printing clichés is a disproportionately high one.

The present invention now aims at the production of master copies for production of printing clichés suitable images or the like under significantly reduced work, Allow time and money to be invested.

According to the invention, grid plates are used, whose in any pattern ge

ao held grid lines or the like from one on one transparent plate and easily removable mass. ' SoE from one Original image a master copy for the production of printing plates can be produced,

»5 when using the grid plate described above, a copy of each part of the picture to be reproduced to be held in a special grid is made in such a way that a grid plate of the desired pattern is placed on the picture and by means of a soft cloth, deer leather or the like., All those parts of the grid pattern can be removed by simply wiping, which should not be kept in the pattern located on the plate. Now this so prepared grid plate is lifted from the picture and a new plate provided with a different pattern is placed on the picture, whereupon the same procedure as described is carried out. Are now velvety 4 ° _t Liehe parts of the image to be reproduced in this way, copied, so the individual screen copies are combined by superimposition in the correct position and is made a light copy of this grid assembly, from which then the printing plate can be removed immediately.

Another possible combination of grid patterns results from the fact that · of each one and the same grid pattern positive 5 <> negative plates can be produced by which then especially when used by leaving overlapping partial areas Black and white effects can be achieved.

In the drawing, the execution of the method according to the invention is for example shown, namely shows:

Fig. Ι a series of differently patterned grid plates with copied <»o Image sharing,

Fig. 2 the grid plate before the compilation of the overall picture and

Fig. 3 the final image obtained from the composition of the grid plate, equipped with the desired *> 5 th grid patterns, which can be used directly to remove the printing cliché.

The grid plates can also be designed as photographic plates, whereof then the mass from which the patterns applied to the transparent plate are made are formed, is a photosensitive composition. In this case, using · each different rasterized photo plates the picture under respective cover of the not needed place a series of raster images created, which then superimposed and copied into a single image in the desired halftone pattern.

When using this grid plate manufactured as a photographic plate the procedure is such that the original image to be reproduced is covered in all of those parts \ velche will not be in the same grid plate as the one currently used worn pattern reproduced

should be like this. A copy is then made by one of the usual photographic methods of the parts of the image to be held in the same grid using a photographic Apparatus manufactured. To

The development of the exposed grid plate remains then only the desired grid positions on this. If all the necessary grid plates have been completed, then the previously described manner a copy of the collapsed grid plates created. In this case, of course, there is no grid that is used to create the overall picture would have to be removed. It is also possible to use a positive and negative plate from each sample as shown in Fig. 2 to manufacture. When they are placed on top of one another, they are then left on top of each other Partial areas an overall pattern according to Fig. 3 with a special black and white effect achieved.

Another embodiment of the method is that the grid plates are appropriately patterned through slits and matched with the original image copied on a photographic plate desired compilation copied and then compiled into the finished final image be, whereby the. the same effect arises as described above.

Claims (4)

Patent claims: i. Process for the production of master copies for printing plates, thereby characterized in that transparent plates are successively brought into contact with the original image, on which in A grid of an easily removable mass is applied to any pattern is, and that those parts of the grid pattern are removed on each plate that are in the relevant grid should not appear in the picture, whereupon by superimposing these "plates, contain the partial areas of the image as a grid, a master copy is created that contains the image in the form of various rasterized areas and directly for production a printing block is used. 2. The method according to claim i, characterized in that positive and negative plates one and the same grid pattern, in which the overlapping partial areas stand still, can be used. 3. Embodiment of the method according to claim r, characterized in that that the individual copies to be superimposed are partially covered by a photograph on such Photo plates are made on which the photosensitive layer is in the form of any Raster is applied. 4. grid plates for performing the method according to claim 1 to 3, characterized characterized in that the same consist of stencil-like plates provided with randomly shaped grid slots. 1 sheet of drawings