Was there a specific paint color for submarines?

There were specific colors and patterns for most Navy ships. For surface ships, this can have been fairly complex. Patterns can act as camouflage and can even confuse the eye about which direction the ship is going.

Paint colors also mattered to submarines. They wanted to be less visible on the surface. Initially, submarines were all black. This was thought to be the best color when on the surface at night as well as when submerged. That turned out not to be the case.

Black was the best color for horizontal surfaces. Seen from above, the deck and other surfaces can blend in with the depths of the ocean. Those surfaces remained black in the new paint schemes.

The vertical surfaces of the submarine were a different matter. Someone pointed out that black is actually too dark at night. Submarine captains were skeptical, but experiments were done to determine which shade of dark grey would be less visible. Captains were convinced when they saw that a dark grey submarine was actually harder to spot than a black one.

Submarines were painted all black again once snorkels were added and boats could be submerged most of the time.

NOTE: There is an old Navy adage: If something moves, salute it; if it doesn’t move, move it; if you can’t move it, paint it gray.