Ok, so I've figured out that adding make-up and tattoos using just a color math node set to multiply  is easy so I do it all the time (I hate changing a texture that took me days and days to paint). I have a problem that I haven't been able to figure out though. Anything colored will look great, but:

How do you put opaque white onto something ?!

I've been struggling with this for quite some time, how to add white in Poser. The best I have been able to do thus far is to make skin lighter (like tan lines) but so far no opaque white. I know that in theory it sounds easy so I have never bothered to ask here. I am at my wits end. Any node gods out there wanna tell me how or at least point me in the right direction?

A map/mask similar to a trans map applied to the strength of the color map... ? maybe

have you tried an HSV node?

not a bad idea but I tried that.

try to imagine adding geisha make-up onto victoria 4 without changing your original texture. just by adding the clown make-up color map in the material room. changing the strength of the original texture doesn't add the make-up it just pales out the original skin.

HSV does really funky things with it. I don't know enough to set the thing up right.  My best attempts at doing this where using HSV, but wound up making the make-up almost glow and partly see-thru.

in a paint program I'd just add a layer and be done with it. opaque white is my nemesis.

how about a white colour node and a blender?

I guess I'll need to post WIP screenshots and such.
already tried a blender node. I'll do a couple quick renders and post them with a low-res version of my face paint.

In you paint program, make two layers above the base.  Import your V4 face map as the base, in the second layer above your base, paint white the area say over the eyes.  In the layer just above the base, fill it in black and save as a .tiff, bmp etc. name it eye shadow.

Then in the material room, connect a blender node between your image map node and Posersurface diffuse color channel, then connect the texture image you just created to the blending channel, then number in the blending channel to 1 and you should have an opaque white mark above the eyes.  Jan

original image plugged into a subtract node then a bias node which is plugged into the blendin value. original image plugged into input #2 of the blender node with skin plugged into input #1 of the blender node.

Numbers matter. The Blending value must reach 1 in order to fully switch to the second color.

The default multiply factor of the Blending node (what it says when you have just added one) is not 1. It is .5, which means that what you plug in, it's strength is CUT IN HALF. It's like your mask isn't fully on.

In Poser nodes, a numeric parameter is a number and a place to plug a node. When you don't plug a node, the value is the number. When you do plug a node, the value is the number TIMES the node's value. Colors work the same. Every color parameter has a color chip showing its value. If nothing is plugged in, then the chip is the value. If something is plugged in, the parameter value is the chip multiplied with what is plugged in. WHITE is the color equivalent of 1.

0 (BLACK) and 1 (WHITE) are incredibly important numbers. They have unique properties, but so do many other numbers. What is fascinating is how many times these numbers show up. In a shader, the number 1 (or the color WHITE) is extremely important. If you're using some other number or color in some math, you better be sure you know why.

As to how you should be using this.

Start with just the color map.

Add a Blender node.

Value_1 and Value_2 should be WHITE. The blending value should be 1.

Connect your color map to Value_1.

Connect your mask to the blending value.

All should be revealed.

Quote - original image plugged into a subtract node then a bias node which is plugged into the blendin value. original image plugged into input #2 of the blender node with skin plugged into input #1 of the blender node.

So you're trying to make brighter areas just go white? You don't have a separate mask?

You didn't say any numbers, so I have to say again - numbers matter.

If you're taking the color - x, then the value of that is far less than 1, but I can't tell you exactly what you did wrong or should do if I don't know x.

The bias node can increase or decrease a number, so again since you didn't show or describe the numbers, I don't know what goal you're attempting to achieve with the bias.

You're trying to plug that in as the blending factor, but it never is 100% because you made a number that is much less than 1.

Using 100 * (color - x) as the blending factor will produce a far different outcome.

Luckily I actually understand you this time BB, I know something about color math from using blending modes in photoshop and I know that you have said that anything that can be done with a blending mode can be done in poser with  node.

the render with a blender node I already posted has the blending value set at 1 with the bias node output plugged into it. I had to use a bias node to increase the strength of the mask after inverting it with a subtract node, it just comes out partly see-thru though, acting like a screening layer instead of being opaque.

I edited my previous post. Sorry - read it again.

When you use

color - .5

for example, you can't bias that all the way to 1. Bias never takes anything up to 1 or down to 0, except what is already at 1 or 0.

You need the number 1. You do not have the number 1. You have some number less than 1, no matter how you set the bias.

Bias can only alter middle values between 0 and 1 and they remain middle values at all times.

If the maximum value of the color - x is, for example, .2, then you have to multiply it by 5 just to get back to 1.

I'm trying to parse all the input. I was hoping to avoid using a mask since making a mask from a partialy transparent image that is white and grey is a huge pain.

ultimately I was hoping to add white make-up as easily as I add other colors. A simple color math node set to multiply works wonders, but you can't multiply white. Some tattoo design have white in them and so do some make-up designs.

Sorry to be a pain, I'm just frustrated with not being able to use white in make-up and tattoos. I am trying my best to follow you though.

Well show me a screen shot of what you're doing.

I've shown screen of this setup at least 100 times and you should be able to find some of them. Search post by me, blender blending as the text.

Or show me yours and I'll tell you what is wrong.

My wife won't let me ignore her anymore so I may be gone a while. Like 2 days.

did I mention I'm using a VSS made skin shader? kinda makes screenshots tricky.

Quote - ultimately I was hoping to add white make-up as easily as I add other colors. A simple color math node set to multiply works wonders, but you can't multiply white. Some tattoo design have white in them and so do some make-up designs.

If you're looking for the screen blending mode from PS, that can't be done with a basic blend node AFAIK. You'll have to redo the math that screen uses, which is something like Result = 1-[(1- color A) x (1 - color B)]

If you're looking for the overlay blend mode, that's a bit more complicated as it uses both multiply and screen, switching between them depending on whether the top layer's colors are below or above 0.5

Making the blender node the last link in the chain seriously overexposed the white ...so I plugged the original skin map to it and plugged the blender node into the first place where the original skin map went. Needless to say the problem was WHERE to plug it in, not how ....

I can only humbly beg for Bagginsbill's forgiveness, he really HAS told people many many times about the blender node. I know how to use the blender node and there was a bit of a misunderstanding about that. I had tried a mask in a blender node before and nearly beat my computer to death when I saw the results, as I showed in my previous render.

Lessons learned: 1) Read "nodes for dummies" again. and again. and again.
                                 2) Make sure to be more specific when asking for help.
                                 3) Where you plug a node in a chain is just as important as what you plug in.

Actually I just wanted to get the effect of a "normal mode" since the facepaint is just painted on a transparent background, but figuring out the overlay blending mode in Poser would ROCK!

In a perfect world, Poser would read transparency in images. looks like it still has trouble.