I am an amateur photographer. Nikon cameras and lenses, Aperture is my primary photo editing software. I also use the Google NIK tools for adjusting and image effects. How do I calibrate my monitor? And especially, how do I get pure, pure whites? The calibration tool in Sys Preferences confuses me. By that I mean, which of the color profiles (such as Adobe RGB) does a guy use? By the way, I don't commonly print my photos.