Pigment
From BME Encyclopedia
A pigment is a coloring agent. Pigments can be natural or synthetic, but in the case of Tattoo Ink they are generally metal salts or even plastics. In tattoo ink, pigment is suspended in a carrier solution which keeps the pigments evenly mixed, applicable, and clean. Pigments - and therefore tattoos - may break down when exposed to the sun, so you should wear sunscreen over your tattoos if you're spending a day at the beach or going to a tanning salon.
