I don't think you need any array.
You can simply change the color of the form by using the color property of the form object; in a method on the form:
self.color=blue
and that's all.
Remember that colors are, as always in windows, longints, and that you can use the predefined constants:
Black, Blue, Brown, DarkBlue, DarkCyan, DarkGray, DarkGreen, DarkMagenta, DarkRed, Gray, Green, LightBlue, Magenta, Red, White, Yellow, Transparent
and also clBtnFace and similar constants to read system configured colors (those the user set in the screen control panel).
Remember also that you may need to change the PAGE color, if it's not transparent.
Bye!