A percale sheet is a type of cotton sheet, and the name percale refers to how the cotton threads are woven. Percale is a type of plain weave and is used mostly for bed sheets.
Plain weave, which is also called flat weave, means that the threads that run vertically and the threads that run horizontally cross each other one at a time. This makes for a very strong fabric. With percale, there are no fewer than 180 threads per square inch, so the fabric is not only strong but has a fine "hand" and finish. The feel of the sheets is even more luxurious if the thread count is higher, but a thread count over 400 may cause a pure cotton sheet to wrinkle. Because of this, some manufacturers weave in synthetic fabrics such as rayon or a wrinkle-resistant fiber such as silk. Pale colors also contribute to the soft feel of the sheets, as heavy dyes make the fabric stiff.
The cost of percale sheets depends on the thread count and the type of cotton that is used. Egyptian and Pima cotton have long staples, or fiber threads, and tend to be more expensive. Percale sheets can be washed in warm, but not hot water, which can shrink the threads. Chlorine bleach is not recommended. After washing, sheets can be tumble dried.