Authenticity is a term used by philosopher and critic Walter Benjamin to describe the qualities of an original work of art as opposed to a reproduction.
Benjamin first used the word in his essay The Work of Art in the Age of Mechanical Reproduction, where he describes an original work of art as having ‘authenticity’. By this he means it has a presence in time and space, and a unique existence in the place it happens to be.
A reproduction of a work of art lacks ‘authenticity’ as it is not possible, when reproducing the work of art, to establish the exact conditions in which the original artwork was created. But it is possible, by reproducing a work of art, to call into question the original artwork’s authenticity, as reproducing it has undermined the artwork.
For this reason an original work of art is considered by the art market to have a higher value over a reproduction because it contains this authenticity.
Authenticity can also relate to forgery, in order to establish whether or not a work of art was actually created by the artist it pertains to be by.