It is important to think about the emotional affect of colour when considering a composition, this is particularly relevant with abstract or semi-abstract painting as the composition loses the object normally presented to the viewer and will therefore rely on colour, texture and line to provide a subject, if indeed there is one. These are generally accepted emotional values associated with colours.
As I have been thinking about colour a lot since reviewing the colours used by Matisse, Van Gogh, Picasso, Derain and others, I felt this was relevant.
Mars (Warring Planet)
Warning (when with Black)