Help System (web edition)

For each integer value n in the SHADING list, the color may be given
by a COLOR(n) specification of the form
COLOR(n)=c,m,y,k where c,m,y,k are numbers on the interval (0,1) and
give the color components according to the CMYK (Cyan, Magenta, Yellow,
blacK) system. These values are used as such in PostScript but in GPLOT
they are converted into the RGB (Red,Green,Blue) system.

When COLOR(n) specifications are used, also texts produced by VALUES and
LABELS specifications can be set individually by SHADING of the form
SHADING=c1/t1,c2/t2,...
where c1,c2,... are color numbers as in SHADING=c1,c2,... and
t1,t2,... are color numbers for VALUES and LABELS texts.
For each c1,c2,...,t1,t2,... a corresponding COLOR() specification must appear.

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This example shows how the default colors 2,3,4 in GPLOT
are close to selected COLOR codes 5,6,7 given below:
GPLOT RGB / Activate this command!
DATA RGB
N R1 R2 G1 G2 B1 B2
A 1  1  1  1  1  1

SHADING=2,5,3,6,4,7  GAP=0
COLOR(5)=0,1,1,0.3
COLOR(6)=1,0,1,0.3
COLOR(7)=1,1,0,0.3
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COLOR(n) specifications should be preferred especially in cases where
the final plotting is to be done by PLOT (PostScript).
The CMYK colors in PostScript may slightly differ from those used in
GPLOT depending on the device used for PostScript plotting.
Usually a small adjustment in the last CMYK component (Black) will
improve the correspondence.

  S = More information on SHADING