Originally Posted by Daviskw
With a gray background it is easy to put any background you like.
In my example I first darkened a duplicate to get the gray close to 128.
I then inserted a new background above it with the layer mode set to overlay.
I then added a mask to the duplicate and masked in the original color very loosely.
This technique will show every hair.
Wow, great result! I guess focusing on getting even lighting on the background around the hair is important if I want to use this technique.