I have noticed that in several pictures of the Olympic's launching, the ship appears white, But in Titanic's photos, the hull is fully painted. Am I just looking at bad pictures, or what?
Yes, I agree with Dan and Parks.
Often, important ships and the first of a class were white painted, especially for photographs. One example was the Oceanic of 1899, dubbed ‘the ship of the century’ & Mauretania of September 1906 (launching).
But black was used for hulls at the time when ships were in service, for practical necessity; among other things, corrosion caused by the sea air was much less noticeable on a black hull. Coal also made dirty marks on a white hull and didn’t show-up on a black one.
Photographs of the third sister painted white while serving as a hospital ship demonstrate this; the rust and coal dust show-up obviously. People sometimes refer to Britannic as a ‘rust bucket,’ but if you removed the black paint and camouflage from other liners of the time, they would look just as bad, if not worse.
Later, after oil-firing had been introduced to the liners, it was possible for white-painted hulls to be applied; Mauretania was given a white hull in the early 1930s when she was used for cruising, but there was still the problem of rust.