In case anyone's trying to remember what macos/iOS does with what they call 'vibrancy' - can't find the video directly anymore but they sorta touch on it here (WWDC 2014 , session 220): https://github.com/ASCIIwwdc/wwdc-session-transcripts/blob/b... "The actual implementation and blending that we do could be a Linear Burn, a Color Dodge, PlusD, PlusL."