Does the material of the plane that is to become the shadow catcher influence the “quality/look” of the shadow in anyway ?
If no, GOOD.
If not…what should it be then ? Principled Shader ?
I think the answer is ‘no’, it doesn’t effect the look of the shadow.
but…
it does effect the objects sitting on it. If it’s a shiny object sitting on the shadow catcher it will reflect the shadow catcher object, and even for defuse objects, it’s worth setting the material to match the surface to an extent. Or you could do tricks with the ‘light path’ node to mean the object won’t be reflected, etc.
Do elaborate ! Exciting !