There is a really strange behavior I cannot explain. After further testing, it looks like it's the 1/IOR part that not working here. On the render result at least as the material preview and the rendered material do not follow the same behavior.
Weird stuff.
This is how it is supposed to look like when you use my setup
And this is how a normal Corona material looks like without the IOR combo. A reflection pass that only a mother can love.
Looks like the exposure inconsistency is related to the gamma 2.2 part in the IOR mask generation.
From the screenshots it looks like you didn't plug the highpassed linear roughness map into the mask slot ? Hard to tell since the screenshot is clipped off.
This material is a perfect example on why we should use cross specular maps as IOR maps
https://quixel.com/assets/tbxkajlkedit:
I overlooked the first response, sorry!
How do you have such knowledge of the technical aspects of lighting and shading?
It all began with Half Life 1 and Sims 1. The first thing I noticed when making textures for these games, was that I could have a static camera and move a light around (at the same distance). Then I could blend multiple photos together with "Lighten", this blending mode will only lighten dark pixels (shadows) and make an "albedo". Back then I didn't know what an albedo was, but it was good enough to import into Wally and make a .wad. I used to hang my cloths up, take a picture and then use the transform tool to turn them into the Sims 1 skin format, good times.
Half Life 2, Doom 3 and Oblivion opened my eyes when it comes to normal map and parallaxing effect. fStrorm still does volume displacement, and it's
fuc***g awesome.
https://fstormrender.ru/manual/displacement. Ever wondered why fStorm users can use displacement on every single plant in their interior, and why the displacement only take like 400mb instead of 200 gazillion terabytes ? This is why.
When Quixel began posting beta versions of roughness, I understood that the next step was to get my hands on some polarizing filter. You can get good quality sheets from
https://www.polarization.com/polarshop. I still use sheets from these guys, even though I have to pay almost double the prize in tax, only to import it.
Since then I've been doing SSS, IOR and albedo tests on my own.
When it comes to SSS. Shorter wavelengths (blue) gets scattered more easily than red light. This is why skin looks red when you shine a light thought it, not because of the red blood. Scatter color in render engines should only be monochrome or blue to be physical correct.
You already know my view on glossiness/ior integration. Again, download
https://quixel.com/assets/tbxkajlk and have a look at the glossiness map. This is not possible with normal maps.