=====Color=====
Tim Robishaw has written a fantastic routine for making colors behave in idl.  Put this line in your start.idl file (or equivalent startup file):
<code>
setcolors, /silent,/SYSTEM_VARIABLES
</code>
and then use color names (!red, !magneta, !white) to make the colors you want, like this:
<code>
plot,indgen(10),/nodata
oplot,indgen(10), color=!blue
</code>
Call
<code>
setcolors, /test
</code>
to see if it's working (if it doesn't work right away, try it again --- you may need to have a plotting window going before it works).

{{:setcolors.pro.txt|setcolors.pro}}

If you just want to be able to get the color you want without subscribing to the whole system variable thing, try this routine:

{{:getcolor.pro.txt|getcolor.pro}}

More color magic (computes a 24-bit color values from separated-out R, G, and Bs):

{{:color24.pro.txt|color24.pro}}

===== A different approach =====

See [[http://astro.berkeley.edu/~mperrin/IDL_colors.html|Marshall's notes on color]] for a different approach to making colors work, following the advice of the illustrious David Fanning.