. "temperature between room temperature and 0C. or at 0C. or at a temperature below 0C., if necessary freeing the thus obtained solution from undissolved particles by filtration; centrifuging, settling and decanting or the like and precipitating the dissolved cellulose derivative by means of an acid substance or by means of a salt or a dehydrating agent such as alcohol or by means of any other suitab" . . .