The top quality pigments we sell are the same ones we use to make our own paints and inks. Pigments naturally vary in weight. We package the Dry Pigments by volume in 2 oz. jars. The weight of pigment in the jars varies anywhere from 3 oz. (Cadmium Red Medium) to .3 oz (Lamp Black) depending on how heavy the pigment is. The 1 lb. packages are packed and sold by weight.