The silk filament is produced by the silkworm's two pairs of glands and it consists of two very fine single filaments of fibroin which are cemented together by a sticky substance called sericin. The unwinding and reeling into hank form are complex and very delicate processes which require an extensive use of labor. During the various phases water soaking at various temperatures and even steam is employed. In this way a rather sturdy yarn is obtained for the next working phases. At this point the silk yarn is still very coarse because it contains sericin , a sticky and rough substance, whose purpose is to hold together the two original filaments.
Natural silk is ivory colored.
It is whitened or colored by soaking it for several hours in stainless steel bins containing warm liquid in the desired color. At this point the silk yarn is ready for weaving which is an extremely complex process. This is the most complex and sophisticated weaving of all times. Certain types of silk fabrics undergo the characteristic process of printing. The threads which have been moved reflect light in a different way from the others with surprising optic effects.