[Gnuplot-bugs] Unexpected behavior when using more than one palette

[Lutz M. <ma...@uc...>]

I encountered the following (to me) surprising behavior with gnuplot 4.0. Take 
the following snippet:

set multiplot
set size 0.5,1
set pm3d map
set palette gray
set origin 0,0
set palette defined ( 0 "black", 1 "white" )
splot x**2+y**2
set origin 0.5,0
set palette defined ( 0 "white", 1 "black" )
splot x**2+y**2
unset multiplot

and put it into a file, say, test.gp. Running this script in a gnuplot session 
under X I get two graphs where "white" corresponds to zero on the z-axis, 
i.e., the second "set palette" command affected not only the second, but also 
the first plot. Similarly, using the postscript terminal, both plots range 
from black for z=0 to white for z=200. This is unexpected, because...

a) I think that my X (running at 16 bit depth), and certainly postscript, do 
not run out of available colors, and

b) the second plot doesn't need more colors than the first one anyways, since 
they both require only shades of gray.

Is there any other way to reverse the color range between to graphs in the 
same plot? I tried various combinations of
	set cbrange [0:200]
	set cbrange [0:200] reverse
	set cbrange [200:0]
for the second plot, but none of them gave the desired result.

As in interesting side node, if first execute in a fresh gnuplot session
	load 'test.gp'
and then, after closing the appearing X window,
	set term post; set outp 'test.ps'; load 'test.gp'; set outp
the resulting postscript file "test.ps" contains only one graph. I don't 
understand why that might be.

  Lutz