There are some stock images I'd like to use that have low-contrast effects applied to them and I need to make them look more like there haven't been arty filters applied. (I'm not even sure if that's the best description for the effect I'm trying to undo, I've also seen it described as a milky black.) I've tried using curves, or duplicating the layer and setting it to overlay, but none of these things really seems to look quite right. I think what I want to do is create shadows that don't blend with the dark midtones. Any suggestions would be appreciated.
You can use an Exposure Adjustment layer. Change the Offset to around -.01. You can also set the exposure layer blending mode to luminosity.
Moving the offset slider to the left darkens shadows. If you moved the slider to the right then the shadows become lighter and if done too much can give a washed out look.