Wet Collodion Process
British · Wet Collodion / Ambrotype 1851–1880
The photographer had about ten minutes from coating the plate to developing it, which meant the darkroom had to travel to the subject. This is why war photographers of the 1850s and 60s arrived with a wagon.
Origin
Introduced by Frederick Scott Archer in 1851 and deliberately not patented, which is much of why it spread so fast. It combined the daguerreotype's sharpness with the calotype's reproducibility and displaced both within a decade. It was the dominant process for roughly thirty years, covering the American Civil War, the surveys of the American West, and the industrialisation of studio portraiture through the carte de visite.
Technique
A glass plate is coated by hand with collodion — nitrocellulose in ether and alcohol — containing iodide salts, then sensitised in a silver nitrate bath, exposed while still wet, and developed immediately, because the plate loses sensitivity as it dries. The whole sequence, from coating to fixing, has to be completed in a quarter of an hour. Variants of the same chemistry produce the ambrotype, an underexposed negative backed with black to read as a positive, and the tintype on lacquered iron, which was cheap, fast and durable enough to post home.
The palette
Cool, silvery and high in contrast, with a distinctive tonal signature caused by the emulsion's blue sensitivity: skies go blank white, skin is rendered pale, freckles and red lips darken, and blue eyes photograph unnaturally light. Prints from collodion negatives were usually albumen, which adds a warm brown. The characteristic edge artefacts — pour marks, fingerprints, uneven coating at the plate corners — are visible in most surviving work and are now often imitated deliberately.
Legacy
It produced the largest body of nineteenth-century photography and the great survey and war archives. Dry gelatin plates, which could be manufactured in advance and stored, made it obsolete in the 1880s and effectively created the amateur market. Wet plate has been revived by contemporary practitioners for exactly the qualities that made it difficult — the hand-coated surface, the singular object, the long exposure that requires a sitter to hold still.
Palette
The colours reconstructed for this artist, with the reasoning behind each.
Pigments used: Silver