"most viewed this week on the years"
The Sick Rose is a visual tour through the golden age of medical illustration. The nineteen...
Daguerreotypes, ambrotypes and early tintypes were usually sold in small folding cases. The cases were designed to keep the fragile surfa...
the Tapada phenomenon symbolised women's freedom and indipendence for three centuries 1560-1850 the cyclope eye allowed women t...
An early daguerreotype studio, as depicted in a woodcut by George Cruikshank in 1842. This illustration shows the interior of Richard Bear...
Abrasion due to storage with other items causes pieces of the emulsion (image) to flake off. Humidity in the air the...
View of the moon, multiple exposures Samuel Dwight Humphrey, photographer September 1, 1849 sixth plate On September 1, 1849 Humphrey...
about me "work and lifestyle"
Monday, 3 October 2011
Silver is a common component of most historical photographic processes. Silver mirroring is a natural deterioration, inherent within silver-containing photographic material. Silver is affected by oxidizing agents and silver ions are produced. Once these ions are produced, they can migrate downward through the gelatin layer, towards the support . Hendriks (1991) found that silver ions can also migrate to the surface, and through reduction process at the surface, transform to silver sulfide.
Silver Mirroring is a result of a physical alteration of the colloidial surface of a photograph caused by aging. Over time, the image bearing colloid layer shrinks and conforms to the underlying structure of the substrate or image particles. These physical alterations cause a change in the optical properties and, therefore, in the appearance of the photograph.
Silver mirroring appears as a bluish-metallic deposit or sheen. It can appear iridescent, which may change in reflective light. If not severe, silver mirroring may not be evident in certain lighting conditions. When very severe, silver mirroring can appear bronze in color. On negatives seen in transmitted light, affected areas appear more dense or yellowed depending on the degree of damage