Color gradients in silicone and latex
After doing some research I have a bit more understanding of how to cast solid colored latex and silicone, but how would I achieve a gradient of two or more colors? I'm going to be casting a silicone tongue for my garter snake character, and I want it to have a nice, smooth gradient from red to black:
Also for the tongue, does anyone know how would I go about creating a two-part mold out of Ultracal? I know the stuff is hard as concrete after it's cured, so I don't think I could cut it into separate pieces.