The techniques of montage and collage are closely linked with both requiring the use of different media working across different artistic techniques, including literature, film, sound recording and photography.
A collage is a composition of materials and objects pasted over a surface; a montage is a single composition created by juxtaposing a series of pieces of paper, photos or other media to create an artistic image.
The term collage can refer to both the technique and the resulting piece of art that is produced by combining different media. A montage is created using a variety of techniques across different media and can include three-dimensional objects.
According to Britain's Tate Gallery, the montage is more formal than a collage and is used to create either a complete piece of art or part of a larger work of art.
The photomontage was first used by Dadaists to express political dissent in 1915; it's essentially a collage of photographs used to express an idea.
During the 1920s, the montage was adopted by Soviet filmmakers who used the idea to express different perspectives of a movie scene by cutting between different shots. The montage is often seen as a more politically motivated artwork than the collage.