Quote - It's the diffuse component Kd for Phong shading. Is that what you meant?

I'm sorry, but I don't know enough about different lighting models to know if that's correct or not! Someone else is sure to know which lighting model the Poser Diffuse node implements.

In Poser at least, the Phong node implements a specular lighting model, not diffuse. I don't know if Phong means something different outside of Poser, but it wouldn't surprise me in the least.

"If I were a shadow, I know I wouldn't like to be half of what I should be."
Mr Otsuka, the old black tomcat in Kafka on the Shore (Haruki Murakami)