I open an image/ Background layer. I duplicate that layer, and apply a Levels adjustment that I'm happy with.
Next, I decide to do an "effect" layer such as sharpening, etc., but I want to be able to control the effect of the "Sharpening" Layer with the Opacity Slider, without effecting the Levels Layer below.
If I Duplicate the Levels Layer, or select Layer New-"Layer Via Copy" for the Sharpening Layer, moving the Opacity Slider, on the Sharpening Layer, will also effect the degree of Levels adjustment on the Levels Layer, as it's a Duplicate of that layer.
"New Layer", or "New Layer From Background" doesn't seem to work either???
Best regards,
Leigh
It sounds like you need to be using a Level Adjustment Layer rather than duplicating your background layer and applying Level to that. You can have your Levels Adjustment Layer sitting on top of all your other layers, affecting them all. You can then dupe your background layer and do whatever you want to it while the Levels Adj. Layer affects it independently.
If you're not familiar with Adjustment Layers, read about them in the help menu. I think they will solve your problem.