The use of gouache is not restricted to the basic opaque painting techniques using a brush and watercolor paper. It is often applied with an airbrush. As with all types of paint, gouache has been used on unusual surfaces from Braille paper to cardboard. A variation of traditional application is the method used in the "gouaches découpées" (cut collages) created by Henri Matisse. His "Blue Nudes" series is a good example of the technique. A new variation in the formula of the paint is "acrylic gouache". The term, derived from the Italian "guazzo", also refers to paintings using this opaque method. "Guazzo", Italian for "mud", was originally a term applied to the early 16th-century practice of applying oil paint over a tempera base, which could give a matted effect. In the 18th century in France, the term "gouache" was applied to opaque watermedia, although the technique is considerably older; it was employed as early as the 9th century in Persian miniature and had by the 14th century spread to Europe. Although they are often described as "watercolor", Persian miniatures and Mughal miniatures are predominantly examples of gouache. During the eighteenth century gouache was often used in a mixed technique, for adding fine details in pastel paintings. Gouache was typically made by mixing watercolours based on gum arabic with an opaque white pigment. In the nineteenth century, watercolours began to be industrially produced in tubes and a "Chinese white" tube was added to boxes for this purpose. Gouache tends to be used in conjunction with watercolor, and often ink or pencil, in 19th-century paintings. Later that century, for decorative uses "poster paint" (as it is known in the U.S.), was mass-produced, based on the much cheaper dextrin binder. It was sold in cans or as a powder to be mixed with water. The dextrin replaced older paint types based on hide glue or size. During the twentieth century, gouache began to be specially manufactured in tubes for more refined artistic purposes. Initially, gum arabic was used as a binder but soon cheaper brands were based on dextrin, as is most paint for children. A relatively new variation in the formula of the paint is "acrylic gouache". Its highly concentrated pigment is similar to traditional gouache, but it is mixed with an acrylic-based binder, unlike traditional gouache, which is mixed with gum arabic.