Van Dyke print on handmade paper from 4x5 negative For a little background to these overviews, see here . History: Introduced in 1889 by Arndt and Troos, the Van Dyke print is part of a group of iron based processes which draw on Sir John Herschel's work on the Argentotype silver-iron process developed in 1842. Negatives: A density range of about 1.5 is suitable. Sensitizer: Part A: 9gms ferric ammonium citrate (green) + 35ml water Part B: 1.5gms of tartaric acid + 35ml water Part C: 12gms silver nitrate + 35ml water In moderate light mix A, B and C (in that order) and age for a few days before use. The solution keeps well for about a year if kept in a cool, dark place. At times, owing to trace chemicals in various supplies of ferric ammonium citrate, the sensitizer may develop a muddy precipitate after about 2/3 of solution C is mixed. This can be allowed to settle and the clear sensitizer on top used, or adding about 2.5 gms more of tartaric acid can also dissolv
Adventures in Silver and Silicon