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.
Purple straight line connecting the extreme spectral colors (red and violet) is known as the line of purples (or 'purple boundary'); it represents one limit of human color perception. The color magenta used in the CMYK printing process is near the center of the line of purples, but most people associate the term "purple" with a somewhat bluer tone, such as is displayed by the color "electric purple" (a color also directly on the line of purples), shown below. Some common confusion exists concerning the color names "purple" and "violet". Purple is a mixture of red and blue light, whereas violet