Cirius Resin Dyes may be used to color opaque resins, too. In that case you must use an additional quantity of colorant to overcome the lighter inherent color of the opaque resin.
PolyColor dyes are oil-based for coloring liquid urethane rubbers and plastics. Up to 0.5% dye can be added to the total mixed weight of the plastic
PolyColor Polyurethane Dyes
For Polyurethane Resin - The Compleat Sculptor
Polyurethane Casting Resins: Expert Cold Casting Solutions
Let's Resin 23oz Epoxy Resin Kit - Let's Resin x Daniel Cooper, Crystal Clear Epoxy Resin for Jewelry, Art Resin, Tumblers, Casting
Colorants
Urethane Casting Resin
Epoxy Colors, Dyes, and Tints
Epoxy Resin Pigment - 16 Color Liquid Translucent Epoxy Resin Colorant, Highly Concentrated Epoxy Resin Dye for ewelry DIY Jewelry Making, AB Resin
Epoxy Resin Pigment - 16 Color Liquid Translucent Epoxy Resin Colorant, Highly Concentrated Epoxy Resin Dye for DIY Jewelry Making, AB Resin Coloring
ArtLube-100 Rapid Mold Release
Urethane Resin Dye 1-Oz., 5-Oz & 16-Oz.,Polyurethane Dyes - ArtMolds
Epoxy Resin Pigment - 16 Color Liquid Translucent Epoxy Resin Colorant, Highly Concentrated Epoxy Resin Dye for DIY Jewelry Making, AB Resin Coloring for Paint, Craft - 10ml Each Multicolor
SO-Strong™ Urethane Pigment - The Compleat Sculptor
YRYM HT Epoxy Resin Pigment - 16 Colors Non-Toxic Epoxy Resin Color Pigment for Resin Coloring, Concentrated Resin Dye for Jewelry Making, Art, Paint, Crafts - 0.35oz/10ml Each
Urethane Resin Dye 1-Oz., 5-Oz & 16-Oz.,Polyurethane Dyes - ArtMolds
Let's Resin Epoxy Resin Dye,15 Color Translucent Epoxy Resin Pigment,Non-Toxic Concentrated Epoxy Resin Paint Each 0.35oz,Liquid Resin Colorant for