Well, another overwhelming response. The correct answer is the Western Approaches scheme.
A ship in this scheme was painted completely white on all vertical surfaces. A splinter pattern of very light blue and green (British version only) was applied over the white.
In overcast or hazy weather (which was the rule in the Atlantic) a ship in this scheme virtually disappeared into the background. The blue and green panels were to help hide it in clear weather when it would otherwise stand out like a sore thumb.
A variant was done by Lord Mountbatten's DD squadron which substituted "Mountbatten Pink" (a very light red) for the blue. This made the splinter pattern darker at night than the blue panels did.
Well, enough on that. I'll have to come up with another question....maybe something on tanks this time....