Dupion silk fabric is not “as smooth as silk”. The texture is uneven with intermittent stretches of nubbly thread in the weave. It may be used for elegant clothing and furnishings now, but it had to overcome its original reputation for being an inferior, rough silk.
Making silk begins with gathering heaps of silkworm cocoons. Unwinding them produces a heap of raw silk fibres: fluffy and a bit like freshly-harvested cotton or untreated fleece. Some of the cocoons are really two cocoons nested together with “twin” worms inside. Their fibres get tangled together and cannot be spun into a long, smooth, continuous thread.
This uneven silk was traditionally considered poor quality and not really suitable for spinning. In China it was, and still is, used to pad quilted fabric. If you choose a comforter or duvet stuffed with silk as an alternative to the other “luxury” filling, down, it may well contain fluffed-up dupion fibre.
In 18th century Europe dupion was imported at half the price of good quality silk: most definitely an inferior product. In France the use of dupion for stockings or bonnet-making was prohibited by regulations published in 1743.
Western designers started to appreciate the quirky texture of nubbly silk dupion in the 1920s and 1930s. Around the same time “slub” fabrics were in fashion. Slub had once been a critical name for lumpy yarn or cloth with an “irregular effect given by a warp of uneven thickness”, as the dictionary (OED) says.
Nowadays, dupion may not be silk at all, but polyester with that particular surface. If it is truly silk, it may be good quality silk specially woven to have a dupion look. It works best in plain colours or “shot” woven from two colours. Stripes, plaids or gingham-style checks can also look good in this fabric since the weave echoes the straight lines. It is rare to see dupion used for non-geometric patterns like paisleys or florals.
Dupion is sometimes spelled doupion, and the name is related to the word double.
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