Color tables and mysteries thereof : tv, tvcsl,bytscl

for 'x' window, for colors to activate :

device,retain=2,decompose=0,true_color=24

to reverse color table :

IDL> TVLCT,R,G,B,/GET ;Put the table into IDL variables
IDL> RR=REVERSE(R)
IDL> GG=REVERSE(G)
IDL> BB=REVERSE(B)
IDL> TVLCT,RR,GG,BB ;Load the reversed colors

Make individual entries
http://etcdipanjan.blogspot.com.au/search?q=color