*Post by mattxmal**Post by mattxmal*Does anyone have handy a palette (for use with pm3d) that

approximates

*Post by mattxmal*the visible light spectrum? Doing it by trial and error doesn't

produce the results I would like.

See

http://lists.runrev.com/pipermail/use-revolution/2003-August/021026.html

for an approximation formula. It'll have to be converted into gnuplot,

but it's a start.

THeo

Here is a sample gnuplot's script using pm3d palette functions.

****************************************************************

set pm3d map

set palette color

unset ztics; unset ytics

set samples 200

set isosamples 2

lmax = 780; lmin = 380

k=lmax-lmin

set xrange [lmin:lmax]

set cbrange [lmin:lmax]

set xtics 100

r(x)=x<440?-(x-440)/(440-380):x<510?0:x<580?(x-510)/(580-510):x<=780?1:

0

g(x)=x<440?0:x<490?(x-440)/(490-440):x<580?1:x<645?-(x-645)/(645-580):0

b(x)=x<490?1:x<510?-(x-510)/(510-490):0

f(x)=x<420?0.3+0.7*(x-380)/(420-380):x<700?1:0.3+0.7*(780-x)/(780-700)

set palette functions

f(k*gray+lmin)*r(k*gray+lmin),g(k*gray+lmin),f(k*gray+lmin)*b(k*gray+lmin)

splot x

pause -1

set autoscale y

set ytics

set yrange [-0.1:1.1]

unset pm3d

k=1;lmin=0

plot f(x)*r(x) lt 1 lw 2, g(x) lt 2 lw 2, f(x)*b(x) lt 3 lw 2

pause -1

********************************************************************

I must wrote down without single space character in the long commend

lines, because unexpected line folding occures.

Have a fun!

Namio.