As I’ve previously posted, the default gamma setting in Snow Leopard is 2.2. Previous versions of Mac OS X used a default gamma setting of 1.8.
This gamma change makes all images that aren’t color managed look darker. For most users, this change will be subtle and probably overlooked, however it can be very apparent when using a projector as a display. Some of Techcare’s clients have discovered that when Macs running Snow Leopard are connected to projectors, especially older orange Promethean projectors, colors are washed out and everything is too dark.
The fix is to first turn the contrast on the project up to maximum, then open Snow Leopard’s Display system preference pane. Go to the Color tab, click the Calibrate button, check the Expert Mode option, then going through all the steps and make adjustments to the sliders on each. When asked to select the target gamma, choose 1.8.
Background information: Gamma is a numerical value representing the range of luminance a monitor can display or a digital camera can capture. A gamma value of 1.8 is closer to how text and images appear on paper, and a gamma value of 2.2 (the same value used by all flavors of Windows) is closer to how text and images appear on a home television.