Dr. Ing. Rudolf Hell Gmbh

Linotype-hell Ag

Eggert Jung

Ingo Hoffrichter

Heinrich Wadle

Christian Roes

Klaus Wellendorf

Hans-Georg Knop

Rudiger Sommer

Uwe Gast

Siegfried Klopsch

Hans Keller

Wilhelm Dichter

Ulrich Sendtko

Friedrich Redecker

Klaus Mollgaard

Franz Kuhn

Andreas Wigger

Ernst-August Ziemen

Helma Meintz

Ernst Giesche

Werner Gaulke

A method for defining a new value of K (black) corresponding with a change in CMY components. Original CMYK printing colors are provided. The original CMY printing colors are corrected to create new CMY printing colors. A value of a smallest one of the original CMY colors is sensed. A value of a smallest one of the new CMY colors is sensed. By use of each of these smallest values, the original K printing color value is modified to create a recalculated K printing color value. The recalculated black value corrects for distortion of original gray balance.

Black recalculation for arbitrary HSL corrections in CMY color space

A method and circuit arrangement for selective correction of hues and colors in the production of color separations for polychromatic mixed printing. A hue signal identifying the hues of the scanned colors as well as a color saturation signal and a luminance signal are derived from the measured color value signals acquired when scanning the original. Hue signals, color saturation signals and luminance signals are limited such that they are respectively not equal to zero only for selectable regions. The region of the hue signal defines a hue to be selectively corrected, and all three regions of the signals define a color to be selectively corrected. At least one of the limited signals is combined with at least one of the unlimited signals to form the selective correction signals which are superimposed on the color signals to be corrected.

Method and circuit arrangement for selective correction of hues and

A method and apparatus for isochromatic simulation of a multi-colored reproduction on a color monitor. Before simulation, colors are generated on the color monitor and are matched to corner colors of a printed color chart or the like by measuring or visual comparison. The color values required for the chromatically coinciding generation of the corner colors on the color monitor are measured and allocated to color separation values of the corner colors. The color values required for generating intermediate colors are calculated upon consideration of the printing process of the multi-colored reproduction and are allocated to the corresponding color separation values of the intermediate colors. During the simulation, the color separation values of the multi-colored reproduction are output, modified according to a gradation curve, and transformed into the color values for driving the color monitor in accordance with the previously identified allocations.

Method and circuit arrangement for simulating a multi-colored

In electronic reproduction technology, a method and an apparatus for the production of hue and color separations for single color printing. A color original is optoelectronically scanned to obtain measured color value signals. A recognition region for a selected separation hue is defined in a recognition circuit. A hue recognition signal, which is a measure for the hue deviations of the hues scanned in the color original from the selected separation hue, is generated from the measured color value signals. Corrected color signals are derived from the measured color value signals and at least one corrected color signal is selected for further processing. A recording signal is acquired in a mixer stage by mixing the selected color signal and the hue recognition signal. The recording signal controls a recording element for recording of the hue separation. When color separations are to be produced, a recognition region for a selected separation color is defined and a color recognition signal is generated and mixed with the selected color signal to obtain the recording signal which controls the recording of the color separation.

Method and apparatus for the production of color separations for single

Apparatus and method for producing qualitatively high-grade color images of originals such as copy masters for multi-color or process printing by exposing chromatic material wherein the originals are scanned point-by-point and line-by-line and the color signals thus obtained are converted into color density values for the chromatic material by means of a correction of color and of gradation. The drive values for a color exposure unit which exposes the chromatic material point-wise and line-wise are generated from the color density values using a linearization process. As a result of signal inversion color positive originals can be recorded as color negatives and vice versa. The exposure process can be matched to every chromatic material independently of the nature of the original to be reproduced and the state of the developing process by means of changing the color density values according to an arbitrarily selectable correction function and by means of signal inversion.

Method for point-by-point and line-by-line exposing of color images

In electronic reproduction technology, a recognition circuit for hues and colors in colored surfaces is provided. Before the actual hue recognition, the hue to be recognized is selected and its prescribed or measured color values of the RGB color space are transformed by a first color transformation into chrominance values of the chrominance/luminance color space, whereby the transformation coefficients are defined such that the transformed color locus of the hue to be recognized lies on a rotated X'Y' color coordinate system in the chrominance plane. During the actual hue recognition, the colored surface is opto-electronically scanned and the measured color values acquired are transformed into chrominance values by a second color transformation with the transformation coefficients defined in the first color transformation. By selection of chrominance values and by quotient formation of the selected chrominance values, a hue signal which is a measure for hue deviation of the scanned hues from the hue to be recognized is generated. After combination of the hue signal with an auxiliary control signal, a hue recognition signal is formed, this being unequal to zero when the scanned hues lie within a sector-shaped hue recognition region. For color recognition, a color saturation signal and a luminance signal are additionally generated. The color saturation signal and luminance signal are adjustably limited in terms of amplitude and are combined with the hue recognition signal to form a color recognition signal.

Method and apparatus for the recognition of hues and colors

In engraving of printing forms particularly of gravure cylinders, it has previously been possible to produce run-free color raster configurations for only two colors. The present invention discloses rastering methods for run-free color production of four color impressions and polychromatic impressions.

Run-free color raster for multi-color printing

Method and apparatus for recording color pictures wherein color proofs are made before the actual printing for quality control in multicolor printing processes. The color pictures are exposed on a chromatic material wherein the exposed colors must coincide with the colors which are later to be printed on paper. So as to achieve the color equivalent color picture exposure, the required color density values for the chromatic material of the selected printed and exposed colors are identified with a visual or mensurational comparison of the CIE coordinates. The identified color density values for the exposed colors are allocated to the corresponding color separation values of the colors to be printed and during recording the allocated color density values are utilized instead of the color separation values and are converted into signals for driving a color exposure unit for example a proof recorder.

Method and apparatus for recording color pictures for multicolor printing

Given color reduction depending on tone in four-color printing, wherein the color components of the chromatic printing inks yellow, magenta and cyan are reduced and the amount of black printing ink is increased to compensate for such reduction, a achromatic synthesis is employed up to a gray tone value which corresponds to the full tone of the black printing ink employed and the color components of the chromatic printing inks are again increased proceeding from that gray tone value up to the maximum shadow in order to get desired densities in the overprint.

Color reduction dependent on tone

A scanning method for already rastered masters in reproduction technology uses a special diaphragm for avoiding Moire effects in the re-recording.

Scanning method and scanning diaphragm for suppressing Moire in the

A method for reproducing colored masters in four-color printing where a color reduction or removal (UCR) which differs between the gray area and the chromatic area of the master is utilized in the production of the color separations. In the gray area, a color reduction is done in which a gray balance is produced between the three chromatic printing ink signals Y, M and C. In the chromatic area of the master, a color reduction matched to the respective maximum mean and minimum value of the three chromatic printing ink signals Y, M and C is accomplished.

Method for a reproduction of colored masters in four-color printing

An apparatus and a method for the recognition of colors on a colored image illuminated with a light source of a known spectrum composition, wherein the intensities of three primary colors are measured opto-electronically as color components, which represent the spatial co-ordinates of the color locations in a color space. Prior to color recognition the color components of at least one characteristic test point in each color or color region, which is to be recognized, are measured and noted. The test color components represent the corresponding test color locations in the color space. An identification symbol is assigned to each color component triplet of the test points and noted too. The plurality of color locations in the color space are associated automatically with identification symbols in dependence their respective positions with respect to a spatially close-by test color location, whereby all color locations associated with the same identification symbol appertains to one color recognition region within the color space. Then the colored image is scanned opto-electronically for actual color recognition and the color components thereby obtained are compared with the color components noted, and in case of correspondence, the corrresponding assigned identification symbol is read out, whereby the color components of the colors are verified regarding their correspondence to one of the defined color recognition regions of the color space.

Method and circuit for recognition of colors

A method for the color evaluation of pattern models of fabric, decoration or packaging printing which, in particular, exhibit bleeding color areas, i.e. color areas of differing color saturation and/or brightness, and a color evaluation device with a color monitor is provided for carrying out the method. Color recognition signals characteristic for the individual pattern colors and a run signal, dependent on the respective color saturation, are derived from the color measured value signals obtained through opto-electric scanning of the pattern models. A freely-selectable color signal triad corresponding to the color to be displayed on the color monitor is assigned in a coloration unit to each pattern color and a further color signal triad is prescribed for the background color of the later printing medium. For displaying the pattern models on the color monitor, the color recognition signals in the coloration unit call in the color signal triads. The control signals for the color monitor are determined from the color signal triads called in, from the color signal triad of the background color and from the run signal.

Method for the color evaluation of pattern models of fabric, _decoration

The invention relates to a method of determining the standard color data of colors represented on a color monitor. Within a color represented on the color monitor there is fixed a measurement area in which the color measurement data are determined. From the color measurement data there are calculated the corresponding standard color data of the color selected by the measurement area, taking into account the tube characteristics and the standard color data of the individual phosphors of the color monitor. The accuracy of the determination of standard color data can be increased by multiple measurement within the measurement area. The calculated standard color data are, for example, the starting quantities for a color mixture calculation by means of a color formula computer.

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Schoenberg, Germany

Eggert Jung