Van Dyke Brown is a photographic printing process named for the warm brown tones it produces, reminiscent of traditional Van Dyke paintings. The process uses a combination of iron salts and silver nitrate, with oxalic acid producing a warm brown and tartaric acid yielding a brown-black result. Exposure is typically achieved by contact printing, and tightly-woven fabrics are sometimes preferred over paper due to extensive washing requirements.
Photographers using Van Dyke Brown should work under dim lighting and expose prints for about one minute in sunlight. The developed image is treated in a 1% borax solution, fixed in hypo, and thoroughly washed for at least 30 minutes. Understanding this process allows for the creation of delicate, high-contrast prints with clear, graphic imagery and classic brown tones.