I think there are four basic colors of displayed strings. Not talking about dialogues here. Outside, there are these:
1) Off-white text, the basic spoken color, displayed with the Display String effect in spells, and also "this lock may not have a conventional" etc.
2) Blue text displayed with the DisplayString action, attributed and not. E.g. on entering Ulgoth's Beard.
3) Nice greenish text for "The journey took...", "The party rested...", "The Party Has Gained Experience" and other messages about mechanics.
4) The dark gold of the journal.
I realize that it's possible to change the default colors for the text and the journal, but I'm interested in using Soylent Green 3 to type out messages I want. Is that possible?