WWDC has begun and more information is trickling out about Mac OS X 10.6 "Snow Leopard". I like what I see, but one thing really stood out as intriguing: default gamma will be 2.2 rather than the traditional Mac setting of 1.8. It's one of the many items mentioned on this page: http://www.apple.com/macosx/refinements/enhancements-refinements.html. This is going to be important for photographers and graphic artists in particular.

What does it mean? Gamma refers to the way numerical colour representations are mapped to real colours on the screen – specifically how the luminance is mapped, i.e. how light they appear. Wikipedia explains gamma in full, complete with some neat sample images to show how different gamma settings affect the way an image looks. Windows PCs traditionally use system gamma setting of 2.2 whereas Macs go for 1.8, which means that the same image tends to look darker on the PC than on the Mac, assuming that the image doesn't contain colour profile information, which is the case for most images and videos on the web. Mac users create pictures to look just right on their monitor and are disappointed when the image looks dark and dingy on their PC using friends' machines. Conversely, the PC artist is surprised that the image they create looks bright and washed out on their friends' Macs. And neither of them generally have a clue that this is because of the different gamma settings of the systems!

It seems that Apple have decided to bite the bullet and get in line with the popular 2.2 standard to end this perennial confusion. This is a major step for Apple to take and I imagine they had to think long and hard over it, but it's probably for the best in the long term.