Over the holidays I had quite a bit of free time, so I spent some of it playing around in PS. I played with funky combinations of things like layer blending modes and oddball curve adjustments. Most of these things turned out to be nothing more than weird color/contrast effects, but I did find one interesting thing that might have some useful applications. I thought I'd run this by you folks here on this forum and see what you think of it.
Okay, so here is the basic starting point of my discovery. With a file open in PS, start by adding a Curves adjustment layer & put it in Overlay mode. Your image will have the classic high contrast look of this mode. Now, open the curve adjustment dialog box for this layer, move the black endpoint up to a value of 128 & move the white endpoint down to a value of 128. Voila, your image will now look exactly as it did when it was first opened!!! Isn't that exciting? By moving the curve to a horizontal position at middle gray, we have neutralized the effect of having this Curves adjustment layer in the Overlay mode. As a matter of fact, doing this also neutralizes the blending mode effect for Soft, Hard, Vivid, & Linear Light.
So, are there any practical uses for this? Well, I found that this curve can be used for overall brightness & contrast adjustments by moving the endpoints up & down to lighten or darken the shadows & highlights in general. Then, an adjustment point can be added somewhere in the middle of the curve to fine tune the midtones. I can't decide if there are any advantages or not over using a curve conventionally.
This approach can also be used for general dodging & burning. You have to create two curves adjustment layers, one for dodging & one for burning. For the Burn layer the curve's endpoints are both moved all the way to the bottom. For the Dodge layer the endpoints are moved all the way to the top. For both layers, the layer masks are inverted to Hide All and are then painted with a white brush at varying opacities to get the needed dodge or burn effect.
For both of these uses (overall contrast and D&B) the general effect can be somewhat adjusted by changing the layer blend modes. Soft Light will reduce the effect while Hard, Vivid, & Linear Light will increase the effect. I guess layer opacity could also be adjusted to fine tune the effect.
I've also played around with these horizontal curves at different values in Multiply, Linear Burn, Screen, & Linear Dodge modes to see what possibilites might exist. A lot of this is still undergoing research & development!
Have any of you tried this approach to using the Curves adjustment layer & what did you think of it? If you've never tried it before, how about playing around with it & let me know what you think? If you come up with any improvements or discover anything new, please let us know.