Can you use casting pigments to color the cactus juice?
It depends on what you are talking about. If you mean things like mica powder, then no, it will not color the resin. Liquid dyes will to varying degrees of success. Some liquid dyes will work but in some instances, you will need so much liquid dye that it will affect the cure of the resin. I have tried Transtint dye with limited success (mostly disappointing) and have found that the dyes made by Alumilite (available in the Cactus Juice section) work the best since they are very concentrated and they are reactive dyes meaning they react and cross link with the resin, thus not causing any cure problems. Other dyes will work I am sure but have not tried everything out there.