The paper remembers that although the iconic sign takes on the forms of real, the photograph is theoretically an insecure image. This problem is resolved by following Roland Barthes from his first articles published in the 50s to his last work La Chambre claire.
This focus covers the succesive transformations of Barthes's semiology of image: from his imposant theoretical certitudes to his doubts and his reformation of previous methods. Barthes's final gesture of leaving his research of the code on the benefit of the pure analogy, is studied in terms of recalling the eventual "double language" of the photograph.