Mac OS X v10.6: About gamma 2.2. Jan 11, 2010 6:27 AM Reply Helpful. Thread reply - more options. Link to this Post; User profile for user: Kurt Lang. Set your gamma to 2.2 if you need to ask. The images on your Mac will then match 99% of the world's monitors. A gamma of 1.8 is a throwback to matching tones between LaserWriters and B&W Mac displays.