Dai Nippon Printing Co., Ltd.

Ikegami Tsushinki Co., Ltd.

Koichi Shimane

Satoru Horiguchi

Takeshi Sasaoka

Tsuguo Yaguchi

Kazuhiko Sano

Shigeru Mogi

An apparatus for simulating a color printing process comprises a scanning unit including a table on which four color separation films formed from a color original are placed side by side, a pair of flying spot scanner tubes, four lens systems for projecting raster images of the scanner tubes onto the four color separation films and four photomultipliers for converting light rays passing through the respective films into subtractive primary color signals of cyan, magenta, yellow and black; a control unit for effecting various adjustments and correction upon the color signals and including a zero adjuster, an after image corrector, a continuous tone gamma corrector, a screen gamma corrector, a soft/hard corrector, a negative/positive corrector, a flat etching device, a contrast adjuster, a light adjuster, a shadow adjuster and a partial adjuster; a color reproduction process unit for converting the adjusted and corrected subtractive primary color signals into additive primary color image signals of red, green and blue; and a color monitor unit for receiving the additive primary color image signals and including a color cathode ray tube for displaying a color image. The color cathode ray tube has a chrominance characteristic which can completely display the actual printing colors and has about 700 to 800 scanning lines per frame.

Apparatus for simulating color printing process

In a color reproduction method for reproducing a color image on a color monitor screen by processing primary color signals of cyan, magenta, yellow and black which are derived by scanning color separation films of cyan, magenta, yellow and black, respectively, on the basis of the Neugebauer equations, at first the primary color signals of cyan, magenta and yellow are processed in accordance with specially derived color reproduction equations representing halftone of three additive primary colors of red, green and blue to produce three secondary color signals and a tertiary color signal, and then amplitudes of a paper color signal, the primary color signals, the secondary color signals, the tertiary color signal and the primary color signal of black are adjusted in this order independently from each other. An apparatus for carrying out the above color reproduction method comprises seven multipliers, four inverters and twenty seven variable resistors and by suitably adjusting the variable resistors the colors of the image displayed on the color monitor can be controlled.

Color printing process simulator

Growing community of inventors

Kawasaki, Japan

Koichi Shimane