You can't simple subtract the images, diffuse is 2*X and Specular is X-Y. Also they are stored on the camera in sRGB so you must first make the conversion to Linear space. Its best to do these in shader code. For Gloss just solve for G using the BRDF shader code.
Hello, Being curious and inspired by the work of the Quixel team, I decided to see if I can mimic some of their results and try my hand at constructing my own prototype "megascanner." It's a 1 square meter wooden box with an open bottom and a hinged top. Each interior side has a set of white LEDs each wired to a dimmer…