Abstract: An improved process is provided for the formation of cellulose acetate filamentary material and film. Secondary cellulose acetate is dissolved in a solvent at an elevated temperature and elevated pressure to form a homogeneous solution, with the solvent being incapable of dissolving the secondary cellulose acetate at ambient conditions. The cellulose acetate solution is extruded through an appropriate shaped orifice into a gaseous atmosphere provided at substantially atmospheric pressure. A rapid precipitation or phase separation reaction occurs in the gaseous atmosphere wherein the solvent separates from the cellulose acetate to form a solid filamentary material or film which is subsequently collected. The solid product may be dried to remove remaining traces of solvent. The process is capable of implementation at rapid spinning speeds while utilizing relatively short zones wherein the phase separation is accomplished.