Vintage prints

Each process has a material signature. The daguerreotype is a mirror of silvered metal, unique and irreplaceable. The albumen print, golden brown, spread in the second half of the 19th century. The carbon print, very stable, appeals to collectors for the depth of its blacks.

Identifying the process is the first step of authentication: a process that did not exist at the stated date signals a fake or a later print.

An engraving plate can be reworked, which produces different "states". The first states, pulled when the plate is fresh, are the most sought after. The last states, often pulled after the artist's death, are worth much less.

Identifying the state means comparing with reference copies held in the major print rooms. OIMAP has a network of experts linked to these print rooms.

Archives of studios, agencies and photographers are an essential source of authentication. They often contain contact sheets, printing registers, studio notebooks and correspondence that make it possible to date a print.

OIMAP digitises photographers' archives in cooperation with museums and foundations. This base speeds up expert examination and protects against false attributions.