Color printing process simulator

Claim 1

A method for reproducing a color image on a screen of a color monitor for simulating a color printing process comprising a step of processing primary color signals, which are obtained by scanning a set of color separation films formed from a color original to be simulated, on the basis of color reproduction equations of halftone representing three additive primary colors to derive secondary color signals and a tertiary color signal; and a step of adjusting amplitudes of a signal expressing paper color, the primary color signals, the secondary color signals, the tertiary color signal and the primary color signal of black in this order independently from each other.

Claim 2

A method for reproducing a color image on a screen of a color monitor for simulating a color printing process comprising a step of processing primary color signals, which are obtained by scanning a set of color separation films formed from a color original to be simulated, on the basis of color reproduction equations of halftone representing three additive primary colors to derive secondary color signals and a tertiary color signal; and a step of adjusting amplitudes of a signal expressing paper color, the primary color signals, the secondary color signals, the tertiary color signal and the primary color signal of black in this order independently from each other.

Claim 6

An apparatus for reproducing a color image on a screen of a color monitor for simulating a color printing process comprising means for effecting a gamma correction of ink with respect to primary color signals C, M and Y and a black signal BL which are derived by scanning four color separation films of cyan, magenta, yellow and black, respectively to produce corrected primary color signals c, m and y and a corrected black signal bl; means for receiving the corrected primary color signals c, m and y and generating secondary color signals cm, cy and my and a tertiary color signal cmy; means for adjusting amplitudes of the primary, secondary and tertiary color signals independently from each other; means for summing the adjusted primary color signals c, m and y, the secondary color signals cm, cy and my and the tertiary color signal cmy on a basis of color reproduction equations of halftone expressing three additive primary colors to produce output signals c", m" and y"; means for receiving said output signals c", m" and y" from the summing means and the gamma corrected black signal bl and for subtracting each of these signals c", m", y" and bl from a unity to produce output signals (1-c"), (1-m"), (1-y") and (1-bl); first black adding means for receiving said output signals (1-c"), (1-m"), (1-y") and (1-bl) from the subtracting means and for multiplying the signals (1-c"), (1-m") and (1-y") by (1-bl), respectively to produce output product signals (1-bl).(1-c"), (1-bl).(1-m") and (1-bl).(1-y"); second black adding means for receiving said output product signals (1-bl).(1-c"), (1-bl).(1-m") and (1-bl).(1-y") from the first black adding means and the corrected black signal bl and for adding the corrected black signal with adjusted amplitude to the output product signals (1-bl).(1-c"), (1-bl).(1-m") and (1-bl).(1-y"), respectively to produce output signals of red, green and blue colors R, G and B; means for receiving said signals of red, green and blue colors R, G and B and for correcting these signals with respect to paper color to produce paper color corrected color signals; means for receiving the paper color corrected color signals R', G' and B' and for correcting monitor gamma to produce monitor gamma corrected color signals; and means for supplying the monitor gamma corrected signals R", G" and B" to the color monitor.

Claim 7

An apparatus for reproducing a color image on a screen of a color monitor for simulating a color printing process comprising means for effecting a gamma correction of ink with respect to primary color signals C, M and Y and a black signal BL which are derived by scanning four color separation films of cyan, magenta, yellow and black, respectively to produce corrected primary color signals c, m and y and a corrected black signal bl; means for receiving the corrected primary color signals c, m and y and generating secondary color signals cm, cy and my and a tertiary color signal cmy; means for adjusting amplitudes of the primary, secondary and tertiary color signals independently from each other; means for summing the adjusted primary color signals c, m and y, the secondary color signals cm, cy and my and the tertiary color signal cmy on a basis of color reproduction equations of halftone expressing three additive primary colors to produce output signals c", m" and y"; means for receiving said output signals c", m" and y" from the summing means and the gamma corrected black signal bl and for subtracting each of these signals c", m", y" and bl from a unity to produce output signals (1-c"), (1-m"), (1-y") and (1-bl); first black adding means for receiving said output signals (1-c"), (1-m"), (1-y") and (1-bl) from the subtracting means and for multiplying the signals (1-c"), (1-m") and (1-y") by (1-bl), respectively to produce output product signals (1-bl).(1-c"), (1-bl).(1-m") and (1-bl).(1-y"); second black adding means for receiving said output product signals (1-bl).(1-c"), (1-bl).(1-m") and (1-bl).(1-y") from the first black adding means and the corrected black signal bl and for adding the corrected black signal with adjusted amplitude to the output product signals (1-bl).(1-c"), (1-bl).(1-m") and (1-bl).(1-y"), respectively to produce output signals of red, green and blue colors R, G and B; means for receiving said signals of red, green and blue colors R, G and B and for correcting these signals with respect to paper color to produce paper color corrected color signals; means for receiving the paper color corrected color signals R', G' and B' and for correcting monitor gamma to produce monitor gamma corrected color signals; and means for supplying the monitor gamma corrected signals R", G" and B" to the color monitor.