Michael, the USAAF experimented with black undersides, and concluded the paint should be semi or full gloss, which reputedly reflected, rather than absorbed the searchlight beams. Between the wars and early on, AAF used water soluble “temporary” paints, including black. One such experiment was during a raid on Wake, where they used lampblack mixed with soap on the undersides of B-24s. Poor results, it was either difficult to remove, or wore off immediately.
The RAF had special night, smooth night, and I can’t recall what else. The earliest was dead flat, and could remove exposed skin with contact, I hear tell. Dd wonders for the aircrafts speed.