Petersham ribbon, also called Petersham facing or simply Petersham, is a thick, stiff, flexible corded ribbon usually made out of either cotton, rayon, viscose, or a cotton/ rayon or viscose blend of fibres and used as facing by milliners and tailors. Petersham is frequently watered on both sides and comes with a scalloped edge. It is woven so that once steamed, it will take on and support a particular curve of fabric. This makes it useful for obtaining a smooth edge on the brim of a hat, for example, without forming puckers or wrinkles which would result from the use of traditional flat ribbon or other flat fabric.[1] It is also useful as an alternative to bias tape for making fabric conform closely to the shape of the body wearing it— in a corset, for example, or along the waistline of a pair of trousers or a skirt. Petersham is utilized in couture sewing as a form of interfacing as way to stabilize waistbands.[2]
Petersham is very similar to grosgrain ribbon in appearance: both have closely spaced horizontal ridges, but Petersham has a flexible picot edge allowing it to be shaped with an iron, whereas grosgrain cannot be shaped this way.[3]
Petersham is named after the eighteenth century English lord Viscount Petersham who invented an overcoat and breeches made of a special heavy woollen cloth with a round nap surface.[4] For this reason, "Petersham" is often (but not always) capitalized.