Van Dyke Brown Photographic Process
The Van Dyke process is a basic silver salt emulsion, is nicely stable, is easily applicable to many different surfaces and produces a nice deep brown color.
Mix Stock Solutions
Mix each of the chemicals separately in 250 ml of distilled water. Combine ferric ammonium citrate and tartaric acid solutions and then slowly add the silver nitrate solution. Add distilled water to make 1000 ml (32 oz.) of solution. Store in amber bottle away from light. NOTE: Wear rubber gloves during mixing as silver nitrate can cause burns and penetrate the skin.
Paper or organic fabric such as cotton, linen or silk can be dipped in the stock solution or brushed on to coat as evenly as possible.
Dry coated material
Hang to dry. Hair dryer can be used.
Contact print: 20 or more minutes under UV fluorescents; 10 to 15 minutes in sunlight; approximately 30 minutes with photo floodlights. Cloth needs approximately 50% more exposure time.
After exposure, wash for about five minutes in running water. More absorbent cloth or paper needs to be washed longer to avoid developing stains.
Now immerse print briefly in tray of water with small amount of regular photo paper fixer. One part fixer to 20 parts water. This will change image color to dark brown.
Wash about 15 minutes.
The print will darken as it dries.