I'm a doctor, not a mechanic
From Unreal Wiki, The Unreal Engine Documentation Site
UT2003 :: Object >> Material >> RenderedMaterial >> ConstantMaterial >> ConstantColor (Package: Engine)
A material that generates a constant color. Useful for creating tints and other effects.
- Color Color
- The desired RGB color. The A (alpha) value of the color won't have any effect if you just apply this directly to a surface: run it through a FinalBlend with FrameBufferBlending set to FB_AlphaBlend.