This issue isn't specifically about image processing, but this is the closest topic board I could find.
Recently I partitioned my Mac into separate partitions for Snow Leopard and Mavericks. I now typically use the Snow Leopard partition only for scanning. But I just noticed a very strange phenomenon when using Snow Leopard: images or other graphics will have a "sparkle" effect (small flickering dots, smaller than a pixel) in a certain range of colors, e.g., purple HEX #663399 and red #cc3333, or in certain regions in the gray scale. The effect is visible in any application (Photoshop, Preview, etc.), or even in application graphics themselves (e.g., the blue splash screen that appears when Photoshop first launches). I've attached a simulation of the phenomenon that I re-created as an animated gif.
When I restart the Mac into Mavericks, the phenomenon disappears. The images appear normal (no "sparkle").
Any ideas what is causing this phenomenon? And why only in Snow Leopard?
