Removing Gamma from Alpha LWF
From VFXPedia
In my experience, when you remove Gamma-compensation from sRGB images with Alpha for correct Linear Workflow, you should apply the same Gamma operation to the Alpha channel. Thus, you get read of dark edges around your foreground objects and the result of compositing looks better. But a more physically correct method is to perform the Gamma operation with predivide/postmultiply operations (Thanks to Chad for clearing this up).
