Photographs are mixed materials and therefore complex. They combine organic support (paper, cloth, …) or inorganic (metal, glass, …), extremely diverse printing and fixing processes or stabilizing and retouching techniques.
Our role at CARAA is to determine the most appropriate physico-chemical tools that will help identifying and differentiating scientifically these different manufacturing processes.
• The photographic support
Determining the composition, the stability in air and or under light of a photographic metal support (e.g. daguerreotype) or paper support (albumen, salt, aristotype ..) is essential for the restoration and long-term conservation of the photograph.
• The printing processes
The non-invasive analyses performed at CARAA can help to determine precisely the technique and salts used to print and fixe the image. In addition to distinguishing between the chemical elements used (palladium, platinum, gold, silver, uranium, mercury ..), the determination of the relative contents of these elements is crucial to understand the technology and the intention of the artist during the printing process.
Works analyzed : E. Weston , M. Mather, anonymous models of uranotypes, etc.