Carrageenan each plant weighs approximately 1 kg. The "E. cottonii" variety has been reclassified as "Kappaphycus cottonii" by Maxwell Doty (1988), thereby introducing the genus "Kappaphycus", on the basis of the phycocolloids produced (namely kappa carrageenan). After harvest, the seaweed is dried, baled, and sent to the carrageenan manufacturer. There the seaweed is ground, sifted to remove impurities such as sand, and washed thoroughly. After treatment with hot alkali solution (e.g., 5–8% potassium hydroxide), the cellulose is removed from the carrageenan by centrifugation and filtration. The resulting carrageenan solution is then concentrated by evaporation. It is dried and ground to specification.
Shades of purple halfway between violet and magenta and thus fits the artistic definition of purple. Using additive colors such as those on computer screens, it is possible to create a much brighter purple than with pigments where the mixing subtracts frequencies from the component primary colors. The equivalent color on a computer to the pigment color red-violet shown above would be this electric purple, i.e. the much brighter purple you can see reproduced on the screen of a computer. This color is pure purple conceived as computer artists conceive it, as the color on the color wheel halfway between color wheel violet