To provide a lithographic ink printing method which makes it possible to reproduce, with four colors of yellow, red, indigo and black, the color reproduction domains of RGB which have been expressed so far by printing with six or seven colors including orange, green, purple, etc. in addition to four process colors of yellow, red, indigo and black.
In lithographic printing which uses yellow ink, red ink and indigo ink and also black ink, each color ink is printed solely or by overprint with others within the limits that the density values of yellow, red and indigo are 1.40-1.44, 1.52-1.56 and 1.63-1.67 respectively. On the occasion, printing is so made that the chromaticity of the overprint based on an L*a*b* color model ranges within the limits of L*: 51-56, a*: 65-70 and b*: 56-61 in the case of the overprint of red ink yellow ink, L*: 47-53, a*: -77--83 and b*: 25-32 in the case of the overprint of indigo ink yellow ink and L*: 23-29, a*: 28-33 and b*: -63--68 in the case of the overprint of indigo ink red ink.
SASAKI TAKESHI
YOSHIDA SATORU
ONO TAKAMOTO
KURITA EIJI
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