User:Ctanguay/Sandbox

Mordançage is an alternative photographic process that alters silver gelatin prints to give them a degraded effect. The mordançage solution works in two ways: it chemically bleaches the print so that it can be redeveloped, and it lifts the black areas of the emulsion away from the paper giving the appearance of veils. Once the emulsion is lifted, it can then be removed or manipulated depending on the desired outcome. Areas where the emulsion was removed appear to be in relief. These prints can become oxidized during their creation, further altering the tonality of the image.

History
Mordançage was created by Jean-Pierre Sudre during the 1960s. While he is credited with the creation of Mordançage, it is based on a late 19th century process known as etch-bleach. This process has also been referred to as bleach-etch, gelatin relief, or reverse relief. Etch-bleach was first documented in 1897 by Paul Liesegang and was originally used as a reversal process for film negatives. Within a year, a man named Andresen suggested using hydrogen peroxide and hydrochloric acid in the process in the place of ammonium persulfate. Later references to the etch-bleach process show a chemical composition that is very close to that of mordançage - the only difference being the use of citric acid in place of glacial acetic acid. Sudre refined this technique and dubbed it "mordançage." His process has since been adopted by some of his students, and has spread from there.

Chemistry
To make the solution, the materials should be combined in the following order.


 * 750 mL distilled water
 * 10 g copper chloride
 * 50 mL glacial acetic acid
 * 25 mL 30%-35% hydrogen peroxide
 * Water to make 1 liter

Process
For fiber based or resin coated paper:
 * 1) Print should be placed in the mordançage solution, and left in for twice the time it takes to bleach.
 * 2) Rinse print well.
 * 3) Optional: rub off disintegrating emulsion.
 * 4) Redevelop the print. A variety of fresh or exhausted developers can be used at various dilutions, as well as some toners. Different developers and dilutions will result in different tonalities in the paper.
 * 5) Remove print from developer and rinse. The print can be fixed in fixer at this point. Neglecting to fix the image can lead to the oxidation of the print, however these color shifts can be a desirable effect.
 * 6) Wash carefully. Any veils that have developed will be fragile, and difficult to wash without causing them to pull away from the paper.
 * 7) Dry the print. It is advisable to use separate screens than are used for archival prints, as the mordançage solution can contaminate them.

This process can be altered. If halting the development at any point in the process is desired, the print can be placed in stop bath for three minutes, washed thoroughly, and dried. Alternatively, one can also repeat steps one through four before moving on to step five.

Preservation
Proper fixing and washing of mordançage prints is the best way to avoid unwanted oxidation over time. Photographs that have not been properly fixed and washed can shift color over time. As with any photographic print, storing mordançage prints away from light, humidity, and high temperatures is advisable. The mordançage solution is acidic, so prints should be stored separately to prevent acid migration from contaminating other photographs. Photographs can be interleaved with alkaline buffered paper, or sleeved in polyethylene to help prevent acid migration.