We used white partly because it is a historically-accurate interior treatment for an 1870s Cape. Back in those days, white paint was (and still is) the least expensive yet classy treatment for plaster-and-lath walls. We also used it because white will not alter the look of a painting's color. But more importantly, white is the most popular interior paint color for today's homes. And because we use a blend of natural lighting and lamps that are found in the average home rather than "proper" gallery lighting, a visitor can easily see how a painting might look in her own home.
Before writing this post, I made an informal visual survey online of a number of well-known galleries and museums to see what colors they use. Not surprisingly, nearly all of them use white or something close to it. Certainly, they may have a wall or two painted a darker value with a more assertive color to alleviate the monotony of a large, white space, or, as in the case of museums, to create certain effects for special exhibitions, but white is in the lead.
Here is a great museum, the Guggenheim, with a room painted in what must be approaching pure white:
Rineke Dijkstra: A Retrospective
Installation view: Rineke Dijkstra: A Retrospective, Solomon R. Guggenheim Museum, June 29–October 8, 2012
Photo: David Heald © Solomon R. Guggenheim Foundation.