Thanks The diffuse is dark because working with PBS means you treat the materials your recreating physically accurately. Metals typically don't have much, if any 'Diffuse' or albiedo information. I can't say for certain, but i would assume metal naturally doesn't have much pigment. In comparison to something like dirt, or…
So since you were only working with metals in this case the entire thing is dark, but if you were to have materials like wood, would that appear brighter on the diffuse?