Since we're all asking questions, I'll throw one in of my own. Does anyone know of a exhaustive, comprehensive reference resource for material-room nodes? All nicely, concisely laid out in one place? Bill went through a lot of trouble (in his Matmatic docs) to put together what I would consider the start of a reference resource: it describes the parameters and arguments of all the nodes, but I need something a bit more for dummies. Kinda like what Castle Poser is trying to do, but a bit more complete.

All reference material I've come across has been extremely rudimentary... they'll tell you you can set up a texture map for your material and how to do it. What they don't explain is: let's say it's a bump map... looking at someone else's (er, Bill's) Basic Skin Shader, and there's a Color_Math Subtract between the imageMap (bump map) and the bump channel on PoserSurface. I'm looking at this and going:
"Okay, and Value_1 is white (that's what we're going to be subtracting from) and Value_2 is about middle-of-the-road grey (127,127,127)... that's what we're subracting. So, from my image bumpMap (which is GreyScale), we're going to remove this particular shade of grey, leaving the rest of the shades of grey."

Is that right? Is that correctly interpreted? Took me ages to sort that out...and that's sorted only if I've deduced that correctly. The burning question remains - sorry, I'm a real Dummie, so please bear with me - WHY are we doing this? Does this sharpen the bump aspect? And was by happenstance that it was inserted?

In order to understand the WHY, I feel I need a comprehensive understanding of color maths. I'm terrible at maths... always have been. However, at this stage, I feel I need to learn it enough to understand WHY one would employ a color_math Subtract node. Saying "just experiment" leaves me cold: I have been doing so, writing down results, making minor changes... rendering... changing... rendering... and becoming increasingly befuddled and frustrated, because I walking blindly though this weird nebulum of colour behaviour that is not displaying any sort of predictable pattern. The more I "experiment", the less clear it gets. This is counter-productive. Case in point... here's my scary model with that color_math Subract in place:

and without:

Perhaps my textures are too strong and render the math contributions of little value.
Bill took the time - bless his heart - to exhaustively explain the interaction of bias and gain on an image (starts on page 39 of this thread). There is a graph (which I'm afraid meant little to me... remember, I'm a Dummie, so interpreting graphs is a bit beyond me) and the image, which meant a lot more. I could even see my way clear to converting those formulas - like Clamp(7 * (Bias(x, .7) - Bias(x, .6))) - into nodes. So, that entire exercise was very helpful, Bill... but thick as I am, it doesn't explain how you came up with the idea of using Clamp to modify Bias and Gain in the first place. I need to study Clamp and Bias and Math_function Pov and all of those so that:
1> I know why one would use them and
2> how one would use them and, most importantly
3> I would stop being such a pest on here that everyone has to ignore

When I first started to learn to program in VB, I spent a lot of time getting the main functions clear in my head. As time went on and I wrote more and more code, I had to refer less and less to the manual: I knew what arguments were expected to be satisfied and how that function would serve my needs. And then, of course, I'd start writing UDFs... sometimes, before realizing that VB already had an in-built function. Never-the-less, that functions and procedures manual was my constant companion in those first years (I'm slow-as, but I do get it eventually). Now, I can just sit down and start writing code and the darn thing generally just works... compile almost never picks up errors because there aren't any.

This is what I want to do with material-room nodes. I want to study them, try them out: not blindly, but with a decent grasp of what they do and where one would apply them. I'm obsessed with skin shaders. I will learn this. Just need a decent comprehensive manual or something of that sort that I can refer to.

Monterey/Mint21.x/Win10 - Blender3.x - PP11.3(cm) - Musescore3.6.2

Wir sind gewohnt, daß die Menschen verhöhnen was sie nicht verstehen
[it is clear that humans have contempt for that which they do not understand] 

Metaphor of Chooks