Something like this?
I added a colorramp assuming it is a B&W image-map. If you add a third middle point you have something very close to the PShop levels. Alternatively, you could use a curve RGB node.
this sort of helps thank u,just one question,where do u find the first box named “AOmap” I only can find the ambient occlusion one in shaders and it’s a way different type.
Add/Color/Mix RGB.
I’m not a fan of multiplying diffuse, as we don’t use “ambient” light in Cycles - and it’s purpose, as given by the name is to “occlude ambient light”, not all light. This image explains it.
I would be ok to use it to lower spec (possibly also diffuse) in crevices on a model where the crevice is simplified, as realistically more bounces would be required to reach the eye and thus more energy would be lost. But not for general contact between objects, regular GI handles this well enough.