Toppan Printing Co., Ltd.

Hitachi Electronics, Ltd.

Ikuo Seki

Masahiko Kato

Hisao Katogi

A color separation condition determining apparatus which is useful for determining the operation conditions of the color separation step in a color printing process, comprises a scanning section, a masking circuit, an under-color removal circuit, clip circuits, gradation a correction circuit, color correction circuit, a matrix circuit and a color monitor using a color CRT. The invention further includes a method for correcting color signals in the above apparatus and a masking circuit therefor.

Color facsimile previewer

A density measuring device for easily and quickly measuring the optical densities of original pictures which is characterized in that an original picture is scanned by a scanning device to obtain electrical signals of the original picture, the signals are then converted into secondary electrical signals corresponding to the optical density of the original picture by means of a logarithmic converting circuit, calibration signals generated by a calibration signal generator are added to the secondary electrical signals, and thus obtained combined signals are displayed on a wave-form monitor.

Density measuring device

A method for image regulation of a color monitor in proof-viewing and an apparatus therefor which is characterized in that the image on the color monitor is caused to closely resemble the printed picture, and said method comprises the steps of: scanning separation films of primary colors to obtain primary color picture signals; obtaining secondary color picture signals from the NAM (Non-Additively Mixing) portions which are derived by detecting the maximum value of two of said primary color picture signals respectively; while obtaining a tertiary color picture signal from the NAM portion of said primary color picture signals; regulating said secondary and tertiary color picture signals by multiplying regulation factors; correcting the gradation of said primary color picture signals by said regulated secondary and tertiary color picture signals; and producing an image on a color monitor screen with said corrected primary color picture signals.

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Tokyo, Japan

Ikuo Seki