Abstract: Method for generating harmonic color corrections in a color image. The color image is deposited in an image store and is displayed on a monitor. Color samples of the colors that are to be subjected to a selective color correction are taken from the image with a coordinate input means. Color correction values that act on the colors defined by the color samples are input. In order to obtain harmonic transitions at the locations in the image where the selected colors meet non-selected, neighboring colors, the color correction decreases toward the edges of the color correction area. This is achieved by a filtering of the color samples or color correction values. A color computer calculates the corresponding color correction values.

Abstract: A method for selective color correction of a color image that is deposited in a store and is displayed on a monitor. Color samples of the colors that are to be corrected are taken from the image with a coordinate input means. The color samples are deposited in a color sample memory and form a cloud in a CIELAB color space. This cloud usually has gaps and singular dots. In order to avoid discontinuities, the cloud is filtered and the gaps and singular dots are thus removed. The arrangement of the color samples in the color space can be displayed in a dialogue window in that color correction values are also input. A color computer uses the color samples and the color correction values for the selective color correction of the image. The image corrected in this way can be stored in the store and can be used for the production of color separations.

Abstract: A method for freely selectable substitution of the achromatic part in multi-color printing with the black ink on the basis of a spectrally photometrically scanned original, whereby supporting points in the color space are acquired in the spectrally photometric scanning of the original. Corresponding to a preselected degree, the achromatic part or the complementary color part of the colors of a printing color space constructed multi-color are replaced by the black ink. Supporting point data are photometrically acquired from a color scale specifically associated to a printing process. The printing color space is classified into a color model that is independent of a printing color (HSL Model, FIG. 1) and is displayed in this model. A two-dimensional, non-linear deepening field is formed with luminance values (FIG. 2) and a two-dimensional, non-linear desaturation field is formed with saturation values (FIG.

Abstract: The subject of the invention is a method and a device for generating a digital lookup table for printing inks in image reproduction equipment. Color scan values obtained by photoelectric scanning of an original are used for this purpose. The full colors of the three printing inks and white are measured. Model colors are determined which are in as linear as possible a relationship to the printing inks. This is achieved by a position of the chromaticity range of the print scale such that the primary stimuli of the model colors in the chromaticity diagram are each on one beam of the trajectories of the scale colors through the white point while the triangle set up between the primary stimuli encloses the chromaticity range of the print scale. The scale division of the primary stimuli is adjusted with a cube root to the printing inks. The number of fields to be scanned is determined on the basis of the measured values of the space diagonals. A cubic spline interpolation follows to generate the lookup table.