This might sound like boring old news to those familiar with PP stuff, but it might help others that are new to PP
Was just playing in PSCS2 and was struggling with an image that was taken in strong midday sun and was having trouble with strong shadows (shadows under the eyes on primates)... I didn't want to affect the entire image, so I thought... oh der!!! Why don't I just use a curve layer with a mask on the shadows, doh! There's probably a gazzilion ways to do this, this just seems an easy way for me...
This may seem convoluted when first reading this, but like a lot of PP stuff, once you've done it a couple of times it only takes a few seconds...
1) Make a mask just using one of the (alpha) channels (windows/channels to bring up the pallette), just choose the one (R,G or B etc.) with the most contrast (ie: the strongest shadows) and made a copy of it.
2) Adjust the levels (Image/Adjust/levels) so there's virtually just black and white left, no middle greys, drag in the sliders closer together. You should just have an image that's either black or white, no grey. For example I used 50,1,95 on my image
3) Invert the channel so the black and white is inverted/swapped (Image/Adjustments/Invert)
4) Now rename the new channel to Mask (or something) so you know what it's for later
5) Go back to RGB (click on the RGB channel)
6) Now select the shadows using select/load selection/mask (see that's why you renamed it before
) This should give you the marching ants (^H to toggle them on and off) on the shadow areas
7) Now go to layers and apply a curves adjustment layer and just accept the default, the curves layer will now have a mask with only your shadows selected
8 ) It might help to slightly gaussian blur the mask itself so the transition between affected and non-affected is subtle and gradual, so make the mask itself current (alt-click on the mask and you can see it by itself) and filter/gaussian blur/say 3-5 pixels? Season to taste
9) Then curve away to you hearts content and you'll only affect the shadow areas...
Tah Dah!!! Fill Flash in PP, and it won't hurt your highlights etc...
As mentioned this might seem old hat to those familiar with PP but just thought it might help the newer guys/gals...
Cheers.
