503 Gray Pigment is an epoxy-based liquid colorant used to tint the epoxy mixture gray, providing an even, gray color base for the final finish system. Colored surfaces also tend to highlight flaws and imperfections. The colored surfaces also tend to highlight flaws and imperfections. Cured, pigmented epoxy surfaces are not a final finish surface, but require an additional paint or UV filter coating for ultraviolet protection. Add to the mixed resin/hardener at a rate of approximately one teaspoon of pigment to 8 fl oz of epoxy. More pigments will increase opaqueness and mixture viscosity. One 4 fl oz bottle will tint approximately 1.5 gal of epoxy.