You can add color to almost any material by using a color tint or pigment. Not all color tints or pigments are compatible with all materials.
For example, you want to use urethane colors (such as SO Strong) with urethanes only. Hint: anything that tints urethane paint will tint a urethane rubber or plastic system.
Color silicones with silicone colors only (use only Silc Pig). Using incompatible coloring systems may result in the rubber or plastic not curing. Avoid powder pigments, as they may be hard to disperse and may cause a moisture reaction in urethanes. Start with small percentages of tint or pigment; you can always add more.
Thoroughly pre-mix tint or pigment with Part A or B before adding.