You can open a *.col file just using Notepad.
There are about 60 fields that you can change so you might want to search for an explanation of what each of them changes. (I don't know them all).
They are in this format:
RRR GGG BBB TTT - Red, Green Blue and Transparency
e.g. 135 180 050 100
That makes a snotty green, BTW.
Bena.