SU13803A1 - Method of making printing plates for three-color printing on ceramic products - Google Patents

Description

Modern three-color medical treatments are based on the principle of subtracting colors, i.e. overlaying one paint on another, thanks to which a large number of shades is obtained. The disadvantages of these methods are the dependence on the chemical composition of paints, which is particularly inconvenient when using ceramic paints with their subsequent roasting.

The present invention, a method for producing printing plates for three-color printing on ceramic products, is based on the principle of color matching (a row of underlying colored dots).

The method consists in the following. First, a dot pattern is made, each transparent point of which has the shape of a regular hexagon, of which about a thousand are placed in a square centimeter, with these hexagons arranged so that the distance between them is equal to their double width. A raster can be made by photographing a large-scale drawing on a slide plate.

Seven photographs are taken from a color original: 1st contrast (on the negative, the white spaces of the original will be black, the white ones will be transparent); 2nd contrast through a red light filter (on the negative, pure red and white spaces of the original

will be black, the rest is transparent); The 3rd normal through a red filter and a raster (on the negative, points are obtained whose densities are proportional to the red content in different places of the original); 4th contrast through green light filter; 5th normal through green light filter and raster offset by the width of the hexagon; The 6th contrast through the blue light filter and the 7th normal through the blue light filter and raster, once again offset by the width of the hexagon. Thus, each addend color is sealed by a series of dots (3, 5, and 7) and pure color surfaces (2, 4, and 6).

From the negative of the 1st, they make a transparency (on which the white spaces of the original will be transparent). Then the negatives of the 2nd and 3rd are copied to the negative plate simultaneously and the slides onto it, at which the contours of the images should be combined. They do the same with the following two pairs of negatives 4, 5 and 6, 7, obtained with green and blue light filters. As a result, three slides are obtained, the transparent places of which will correspond to each component of the color.

From the obtained three slides, by means of pigment transfer, flat or cylindrical cliches on metal are produced, corresponding to red, green, and blue inks and giving a multi-color reproduction of the original during sequential imprinting on one surface.

If it is necessary to obtain black parts also (which is not given by the addition of three colors), the fourth cliche for black paint is made by usual methods.

The subject of the patent.

1. A method of making printing plates for three-color printing on ceramic products, characterized in that first: a contrast image (1) is made from the original, a second contrast image with a red light filter (2) and a third normal image with a red light filter and a dot pattern, such

the same contrast pictures and normal with a light filter and a raster, each time moved to the width of a hexagon, but produced with green and blue light filters, after which the negatives 2 and 3 and the danopositive are made from the first negative and are copied onto the negative plate simultaneously the same with the pictures taken with the green and blue light filters, and then with three slides obtained with the usual lines, three cliches are made.

2. To carry out the method indicated in n. 1, the application of a raster, each transparent point of which has a hexagon shape, and the distance between these hexagons is equal to twice their width.