Modification Additive mods

I've added pigment powders to two part epoxy, kneaded in well, & the material worked fine.
Maybe make up a small bit to see how the color cures when the two part is blended together. And prepare enough of the color blend epoxy so you aren't trying to mix up more part way through your project.

 

If you’re confident enough in your color matching and brush skills, acrylic paint thinned to the consistency of milk and applied with a brush can also work. It’s what I did to match Franz’s head to his body - I’d post pictures but I don’t have my laptop. It does look shiny at first but after like 3-4 layers of sealant it’s not a big deal.

 

I have been doing additive mods on some of my dolls, I used to use watercolor pencils to tint the clay part of the Aves Apoxy Sculpt two-part epoxy product. Then I went for acrylics, which I found to be a lot better for tinting the clay. I have personally, never experienced any issues with the clay curing correctly or texture issues of any sort. However, I have read people having issues with some epoxy clays and how they cure or the texture of the clay, when they add pigments to the clay before curing.

I add the pigment to the clay as I mentioned, before mixing the two parts, because I want to have as much time to smooth out the clay before it starts to harden as possible. It does take 24-hours to fully cure. However, for me, it starts to get a bit too hard to create a smooth blended surface after a few minutes of mixing the two parts together (maybe around 25-30-minutes). So, I start with adding the pigment to the unmixed two-part clay, so that I don't shorten the time I have while the clay is still super soft and sticky, to smooth out the surface area. That is what works for me, probably not what will work for everyone.

Here are some progress photos I took, the last time I modified my doll's lips. He has additive mods on his lower eyelids, one of his nostrils, his lips and ears. Hope that helps you some and good luck! (:

 

No problem, glad I can help if I can! (:

You do need to smooth things out a bit before curing and then afterward if you don't have the proper sculpting tools. After a thousand years attempting to customize dolls, I still don't own sculpting tools myself. So, be prepared to do some sanding as well, unless you do have proper sculpting tools, and even then, you'll probably still need to sand some areas to have an even blended looking surface. Good luck!

 

I found that damping my fingers with alcohol helped with smoothing out the surface. But if I damped my fingers too many times the color would end up faded out a bit.
There are lots of useful epoxy sculpting tutorials to check on UTube.

 

Aves Apoxy Sculpt comes in a variety of colors that you can mix 'n match to create custom colors. They have a custom color chart on their site to create specific color mixes, but if you have an understanding of color theory you can also play around with color combos to get the desired result. This is the route I tend to go when it comes it additive mods, as I've had issues with acrylic paint messing with the chemical makeup of the epoxy when I tried using that, and dealt with texture/mixing issues when I tried doing the same with powder pastels (besides the fact that it often dried out the epoxy).