Also see this 
and this tutorial for more information. -adlabs6
Sometimes the camopattern is completely on one layer. Often it is still possible to change the colors with a good result. It only takes more time.
Because we cannot do a replace color on grey colors, we start with giving the grey some real color. No matter what.
We open the channel mixer to do that.
No matter which channel and which slider. We just change one so we get some color in the image.
Ouch, does this look ugly. And when one of the colors was good for you, then that one is also messed up. You'll need to correct it again yourself.
Now the above steps are ONLY needed when you need to change a grey color into a more colorfull color. If that is not the case you can skip the step above and start from here.
Linear Mode
