Pigments are the only truly lightfast colorants as they are chemically inactive and very stable.
Pigments color simply by being there. Our pigments are aqueous dispersed, which means they are finely ground and dispersed in water. Pigments can be combined to create any color either before or after being added to the pulp. The white pulp itself acts as white color, for pastel shades you can simply add a tiny amount of pigment to the pulp. Intense colors require more pigment.