How to Plot with Colors in IDL When Not at PPPL

If you are not using the PPPL helper routines, you can still build a simple named-color structure from the active palette. 

Device, Pseudo_Color=8, Decomposed=0
LoadCT, 39
c = { black : 0, $
      blue : .25*!d.n_colors, $
      ltblue : .40*!d.n_colors, $
      green : .65*!d.n_colors, $
      yellow : .75*!d.n_colors, $
      orange : .80*!d.n_colors, $
      red : .90*!d.n_colors, $
      white : !d.n_colors-1 }
IDL> plot, indgen(100), color=c.yellow
IDL> oplot, indgen(100)/2, color=c.blue

On PPPL systems, the older recommendation was to prefer mk_color when it is available.