I'm not sure if unity imposes some limit, but normally from code it should be easy accessing the clipboard.

It's a question in what space it blends.
Aka is the value your working with in linear space, or gamma space when doing the multiply.
(This does assume the output space is the same ofc!)
Zoltan, if you havn't set unity to use "linear space" then the srgb flags on textures have no effect. (Linear space should only work with unity pro as far as I know).