Collage (literally "gluing") is the assemblage of different forms creating a new whole.

For example, an artistic collage work may include newspaper clippings, ribbons, bits of colored or hand-made papers, photographs, etc., glued to a solid support or canvas.

Decoupage is a type of collage usually defined as a craft. It is the process of placing a picture onto an object for decoration. Often decoupage causes the picture to appear to have depth and looks as though it had been painted on the object. The basic process is of glueing (or otherwise affixing) a picture to something to be decorated, then adding further copies of the picture on top, progressively cutting out more and more of the background, giving the illusion of depth in the picture. The picture is often coated with varnish or some other sealant for protection.

(Collage is sometimes distinguished from photomontage, a collage made from photographs or parts of photographs.)

Surrealism has made extensive use of the collage. Cubomania is a collage made by cutting an image into regular squares which are then reassembled automatically or at random. Inimage is a name given by René Passerson to what is usually considered a style of surrealist collage (though it perhaps qualifies instead as a decollage) in which parts are cut away from an existing image to "reveal" another. Collages produced using a similar or perhaps identical method are called etrécissements by Richard Genovese from a method first explored by Marcel Mariën. Genovese also introduced the "excavation" collage (this also includes elements of decollage) which is the layering of printed images, loosely affixed at the corners and then tearing away bits of the upper layer to reveal images from underneath, thereby introducing a new 'collage' of images. Penelope Rosemont invented some methods of surrealist collage, the prehensilhouette and the landscapade .

Collage was often Called the Art form of the 20th century, but this was never fully realised.

Surrealist games such as parallel collage have used collective techniques of collage-making.

The bible of discordianism, the Principia Discordia, is described by its author as a literary collage.

Reference: Etrécissements by Richard Genovese

Collage and the law

When collage uses existing works, the end result is what copyright scholars call a derivative work. Both the derivative work and the originals have copyrights associated with them.

Due to redefined and reinterpreted copyright laws and hugely increased financial interests, some forms of collage art have been all but outlawed in some areas, for instance in the area of sound collage (hip hop).

Examples of collage art that have run afoul of modern copyright are The Grey Album and Negativland's U2.

See also:

• Collage novel
• List of pieces which use collage
• Decollage
• Digital collage
• Montage and musical montage