The material worked in P12 Superfly;  something has changed.  In any case, I've modified the shader and re-started the render.  It's cleaning up the granularity much better than I could ever get from P12, even after running a P12 render for days.

Poser 12, Poser 13, Poser 14, in feet.  

OSes:  Win7Prox64, Win7Ultx64, Win11

Silo Pro 2.5.6 64bit, Silo 2025.1, Vue Infinite 2014.7, Genetica 4.0 Studio, UV Mapper Pro, UV Layout Pro, PhotoImpact X3, GIF Animator 5