"Crepe" is the name given to fabric having a crinkled or pebbled texture, often used for blouses and dresses with a graceful drape. Almost any fibre may be used, and the fabric can be thin and sheer, fine and opaque, or even heavy. Crepe (alt. crape) fabric may be stretchy, requiring care to cut and sew accurately. Its distinctive surface may be achieved by taking advantage of yarn twist, by arranging a suitable weave structure, by employing uneven warp tension, or by applying a chemical treatment.
The first type utilizes the kinetic energy of two kinds of tightly-spun weft yarns (yarn that runs crosswise)-one S-twisted and the other Z-twisted-(spun so that the twists angle upward to the left or to the right, respectively), which are alternated singly or in pairs in a plain-weave cloth. Upon release from the loom's tension, the springy yarns attempt to unwind within the confines of the web, thus imparting the characteristic rippled surface of "flat crape" or crêpe lisse, as it was known in the nineteenth century. Occasionally this technique is used in both warp (yarn that runs lengthwise) and weft, as in early nineteenth-century Chinese export silk shawls. Georgette is a sheer, crisp, flat crepe; chiffon, a relatively modern fabric, is also sheer and crisp but has a smooth surface. Since the terms "flat crepe" and crêpe lisse seem to have passed from common use, this fine crepe seems to have acquired the default name of "chiffon" as well.
The second type of crepe is made of yarns with an ordinary twist in a weave having small, irregular floats that look fairly bumpy. This method is most effective in heavy fabrics whose larger threads produce an appreciable texture.
The third type of crepe, seersucker, has warpwise puckered stripes resulting from slack tension in the weaving. When the cloth is released from the loom's tension, it relaxes to a shorter length with closer-spaced wefts than the puckered stripes, which are forced to bulge from the fabric plane. It is usually an ideal choice for summer suiting, underwear, pajamas, and children's wear because it sheds wrinkles and needs no ironing.
The fourth crepe requires the application of a special finish that causes the fabric to shrink wherever it is applied. The method was first patented in England in 1822, when a plain, thin silk gauze stiffened with shellac was passed under a heated, engraved copper cylinder to receive embossed patterns. At this time, heavily textured crepes, particularly the printed varieties, were called "crepe." The term for flat crepes-crêpe-eventually came into use for all, no doubt because of the irresistible fashion cachet of anything French.
Plissé-Heated, engraved rollers are still used to impress chemicals on cloth to make puckered "plissé" designs that may not be permanent. However, cottons printed with alkali are permanently altered by shrinkage. Synthetics, being heat sensitive, can be creped handily and permanently not only at the factory, but inadvertently at home by a mismanaged iron.
Mourning Crepes-Well into the twentieth century, crisp, dull black, silk mourning "crepes" were woven in the gum and heat-treated with chemicals to produce the characteristic deeply grooved texture.