Rayon is a manufactured and regenerated cellulose artificial fiber. In Europe it was called viscose. Cellulose from wood or cotton fibers is treated with sodium hydroxide, and then mixed with carbon disulfide to form cellulose xanthate, which is then dissolved in more sodium hydroxide. The resulting viscose is extruded in an acid bath either through a cellophane slot, or through a small hole to make rayon. The acid converts the viscose back into cellulose.