Van Dyke Brown Printing — The Warm Iron-Silver Alternative Process

The Van Dyke brown print — also known as the brownprint or Vandyke — is a beautiful, accessible iron-silver alternative photographic process that produces rich, warm brown images reminiscent of the drawings of the Flemish master Anthony van Dyck. The process uses a sensitiser of ferric ammonium citrate, tartaric acid, and silver nitrate coated on paper, exposed to UV light through a negative, and developed in plain water. The chemistry is simpler than platinum/palladium printing, the cost is far lower, and the results are stunning: deep chocolate browns, warm mid-tones, and delicate highlights on fine art paper. The Van Dyke process sits between cyanotype (the simplest iron process) and platinum printing (the most luxurious) — it produces prints of greater tonal richness and warmth than cyanotype, with a fraction of the cost and complexity of platinum. This guide covers the history, chemistry, step-by-step process, toning, troubleshooting, and creative applications of Van Dyke brown printing.

History and Chemistry

The Van Dyke brown process is a kallitype variant — part of a family of iron-silver processes developed in the late 19th century where a light-sensitive iron salt is reduced by UV exposure and then reduces silver nitrate to form the image in metallic silver. The ferric ammonium citrate acts as the light-sensitive component: UV light reduces ferric (Fe³⁺) iron to ferrous (Fe²⁺) iron. The ferrous iron then reduces silver nitrate to metallic silver, forming the visible image. The tartaric acid acts as a stabiliser and helps prevent premature reduction. The resulting image is composed of finely divided metallic silver — but unlike a modern silver gelatin print (where the silver sits in a gelatin binder), in a Van Dyke print the silver sits directly in the paper fibres, giving the image its characteristic matte, embedded quality.

Sensitiser Formula

The standard Van Dyke sensitiser is mixed from three stock solutions. Solution A: 27 grams ferric ammonium citrate (green form) in 100ml distilled water. Solution B: 4.5 grams tartaric acid in 100ml distilled water. Solution C: 12 grams silver nitrate in 100ml distilled water. To prepare the working sensitiser: mix equal parts of A and B, stir, then slowly add an equal part of C while stirring. The combined solution should be a clear yellow-green. Store in a brown glass bottle away from light — the sensitiser keeps for several months if stored properly. The solution is light-sensitive, so all handling should be done under dim tungsten light or safelight.

Paper Selection and Coating

Choose a high-quality watercolour or fine art paper: Arches Platine, Canson Mi-Teintes, Hahnemühle Platinum Rag, Bergger COT 320, or Fabriano Artistico. Avoid papers with optical brighteners (OBAs), which fluoresce under UV and can degrade the image. The paper should be smooth or lightly textured — heavy texture interferes with fine detail. Under safelight, apply the sensitiser to the paper using a foam brush, glass coating rod, or Japanese hake brush. Apply evenly in overlapping strokes, working quickly to prevent the solution from soaking too deeply into the fibres. Coat slightly larger than the negative area to ensure edge coverage. Dry the coated paper completely in the dark — a hair dryer on low heat speeds this process. The dried, coated paper appears pale yellow-green and is sensitive to UV light.

Exposure and Development

Place the coated paper in contact with a negative (emulsion to emulsion) in a printing frame and expose to UV light — direct sunlight, a UV fluorescent bank, or a dedicated UV exposure unit. The Van Dyke process is a printing-out process: the image appears visibly during exposure, darkening progressively. Check the exposure periodically by opening one half of the printing frame back. The print should be exposed until the shadows are slightly darker than the desired final density (some density is lost during fixing and washing). Typical exposure times: 5–20 minutes in direct midday sun, 10–30 minutes under a UV lamp. After exposure, develop the print by immersing face-down in a tray of room-temperature water. The yellow-green unexposed sensitiser washes away, revealing the brown silver image. Gently agitate for 2–3 minutes. The water will turn yellow as the unused iron and silver salts dissolve.

Fixing and Washing

After the initial water wash, fix the print in a dilute sodium thiosulphate solution (3–5% concentration) for 2 minutes — this removes the undeveloped silver salts and stabilises the image. Do not over-fix: extended fixation bleaches the image and reduces shadow density. After fixing, wash the print in several changes of clean water for at least 30 minutes to remove all residual chemicals. Some practitioners add a dilute citric acid rinse before fixing to clear iron staining from the highlights. Thorough washing is essential for long-term print stability — residual thiosulphate will cause yellowing and fading over time.

Toning

Toning improves the permanence and alters the colour of Van Dyke prints. Gold toning (gold chloride solution) shifts the warm brown towards cooler, more neutral tones — from chocolate to grey-brown or purple-brown — and dramatically improves archival stability by replacing some silver with more stable gold. Gold toning should be done after the initial water wash and before fixing (some practitioners tone after fixing — experiment with both approaches). Selenium toning produces a shift towards cool purples and also improves permanence. Palladium toning produces a rich, deep warm brown. Untoned Van Dyke prints have a warm chocolate-brown colour that is beautiful but somewhat less stable than toned prints — toning is recommended for any print intended for long-term display or sale.

Troubleshooting

Yellow staining in highlights: insufficient initial water wash — rinse more thoroughly before fixing, or add a citric acid clearing bath. Flat, low-contrast prints: the negative is not dense enough — increase digital negative density. Excessive contrast (blocked shadows, empty highlights): the negative is too dense or the exposure is too long — reduce negative density or exposure time. Uneven coating: the brush or rod left streaks — practise coating technique on cheap paper before working on expensive stock. Print fading over months: insufficient fixing or washing — fix for the correct time and wash thoroughly. Mottled or spotted appearance: the paper contains impurities or OBAs, or the coating was contaminated — switch to a quality, OBA-free paper and ensure all tools are scrupulously clean.

Creative Applications

Van Dyke prints are particularly suited to portrait, landscape, and botanical subjects — the warm brown tones evoke nostalgia, warmth, and timelessness. The process adapts well to toning for different colour palettes. Van Dyke can be combined with other processes: coat Van Dyke over a cyanotype for a dual-tone image (cool blue shadows, warm brown mid-tones); or use Van Dyke as a base layer for gum bichromate overlays. The process also works on fabric (prepared cotton, silk, or linen), opening possibilities for textile art, wearable photography, and installation work. The warm brown Van Dyke aesthetic is immediately recognisable and consistently beautiful — a process that rewards beginners and experienced printers alike.