Check the star wars wikia and the newest Guide to Ships. Despite appearances on screen, or even in photos, the SD's were, according to the EU novels, originally painted a bone white- they look a LOT greyer in pictures, tho, don't they? The TIE's were a combination of grey(s) and black. If these are box models,, like from Revell, the base color of the plastic is never even close, but does make a decent base coat color, saving you some primer work. Years ago, when I was making models, I got to the point that I didn't even pop the pieces from the sprue tree before painting parts in the correct colors, after seperating by color needs, of course. Then all I had to do was touch up spots where the flash and sprue were removed, and I could then do framing on clear parts with the touch up paint, since it was out.