In October I'm teaching four classes at ReaperCon. One of these classes is on painting black, white, and red. I'm starting to prepare for my classes, which means writing up outlines and handouts and painting demo figures. This is my demo figure for painting whites.
For me, the secret to painting whites is to not actually use white - use an off white of some tint appropriate to the rest of your color scheme. Then you can still highlight to white, but it'll usually still read as white, or at least white enough.
So I've got four areas I've base coated here, three in various not-quite-whites and one in actual white. I'll probably need to cover the other areas in some brown or something just so they don't interfere with the white samples.
This is going to be a pretty quick project, then it'll be back to other things...or possibly more samples.