I was just explaining the whole Snow Leopard gamma shift this morning to Ali when she asked why some of her recent work was looking so dark. Conveniently, Adobe’s John Nack published an article that includes an interesting history of the issue:

Macintosh, in 1984, introduced us to desktop publishing and to displays with shades of grays. Publishing at that time meant printing presses, and the dot gain of a typical press (then and now) corresponds to a gamma of 1.8. As color management was non-existent at the time (the first color management solutions did not appear until early 1990s, when color displays became more available), Apple’s pick of a 1.8 display gamma enabled the Macintosh displays to match the press.

But now both Macs and Windows are at 2.2, while the HDTVs are all moving to 2.6. Something tells me we’ll have to deal with this again in a couple years.