Box pleats are named for their shape. This wide pleat is formed by tucking fabric on either side of the pleat behind it. The result is a series of rectangular shapes, with a "valley" on either side. Typically, a box-pleated skirt is less formal, as the pleat has a heftier appearance. A box-pleated skirt is used for daytime or weekend wear.
Knife pleats are layered one over the other, with all of the pleats pressed and facing in the same direction. Knife pleats can be wide or thin, creating a broad range of looks for skirts. Typically, the schoolgirl uniform skirt has knife pleats. The thinner and more delicate the pleat, the dressier the skirt. Depending on the length and fabric, a knife-pleated skirt could go from day to evening wear.
Accordion pleats are of equal width, pressed in alternating directions. If you were to push accordion pleats in the same direction, they would become knife pleats. This type of pleat can be very dressy if used in a fine fabric such as chiffon. Accordion-pleated skirts could also transition from day to evening wear.
Cartridge pleats require the most amount of fabric. They are used to gather a very large amount of fabric into a waistline. The release point is the seam or waistline, so this is the most dramatic look of all the pleats. Made up in silk or chiffon, the skirt could be of ballgown quality. Cartridge-pleated skirts are more appropriate for evening events.
Fortuny pleats are fine, crisp pleats originally applied to silk. They are named after the early twentieth-century designer Mariano Fortuny. These pleats do not rely on a seam to keep their shape, as they are set into the fabric. Fortuny's original process remains unknown; however, silk and even synthetic fabrics can be treated to achieve a similar effect. This type of pleating would be used for dressy evening skirts.