Silk: Filament, Finish and Care

Silk is an animal protein fibre formed as a continuous filament by the silkworm. The filament’s fibroin core is coated with sericin; during processing, strands from several cocoons can be unwound together to form one yarn.^[1,2]

“Silk” names a fibre, not a weave. The yarn and fabric structure matter, as do dye, finish and condition. The fibre name alone cannot tell you how a particular cloth was made or how it will behave.^[1,2]

Degumming removes sericin, giving silk more lustre and making it more receptive to dye. Some historical silks were then treated with metallic salts to restore lost weight and improve drape. “Weighted silk” names that treatment, not a grade; the Canadian Conservation Institute warns that it can leave old textiles brittle and especially vulnerable to light.^[1]

Silk fibres lose strength when wet and are sensitive to light. A finished garment also has its own construction, dyes and care instructions, so follow its label. For a historic or fragile textile, ask a qualified conservator before cleaning it; domestic washing and drying appliances can be too rough for delicate fabrics.^[1,3,4]

A cocoon, a filament, a yarn and a woven cloth are related, but they are not synonyms. Holding those stages apart makes an old textile easier to read: the fibre can be silk while the weight, sheen and pattern depend on later construction and finishing. Historical weighting is a separate treatment question, not something a glossy photograph can diagnose.^[1,2]