Wet Plate Collodion
About Us
WET PLATE COLLODION
One decade's process, two beloved objects: the ambrotype and the tintype.
In 1851 the English sculptor and photographer Frederick Scott Archer published a process built around collodion — a syrupy solution of nitrocellulose (“guncotton”) in ether and alcohol — used to hold light-sensitive silver salts on a sheet of glass. Archer chose not to patent it, releasing the process for free public use, and within a few years it had all but ended the daguerreotype era: a collodion negative on glass could be printed on paper again and again, something no daguerreotype could ever do.
The process demanded speed. The plate had to be coated, sensitized, exposed, and developed while still wet — all within roughly fifteen minutes — which is why travelling wet-plate photographers hauled portable darkrooms, tents, and wagons to their subjects, including onto Crimean and American Civil War battlefields.
Two direct-positive variants turned the process into a household name rather than only a studio technique. The ambrotype (a term generally credited to the American patent-holder James Ambrose Cutting, 1854) backs a deliberately underexposed collodion negative on glass with black material, so the faint silver image reads as a positive. The tintype, or ferrotype (patented by Hamilton Smith in 1856), does the same on a sheet of black-lacquered iron — cheaper, unbreakable, and quick enough to make that it became the process of street photographers, fairground booths, and soldiers sending portraits home.
How IT WORKS
1. Pour a collodion solution containing dissolved iodide and bromide salts evenly across a clean glass or blackened metal plate, tilting it to coat the whole surface — this happens just minutes before exposure, under dim light.
2. Sensitize the still-wet plate by immersing it in a silver nitrate bath, which reacts with the iodide and bromide already in the collodion to form a light-sensitive silver salt within the film.
3. Load the dripping plate into a light-tight holder, carry it to the camera, and expose. Collodion is far more sensitive than daguerreotype chemistry, so exposures run from a couple of seconds in bright light to under a minute in duller conditions.
4. Return to the darkroom, or dark tent in the field, immediately and develop the image while the plate is still wet — before the collodion can dry and lose its sensitivity.
5. Fix the plate to clear the remaining unexposed silver, then wash, dry, and varnish it to protect the delicate emulsion underneath.On glass backed in black, or on black-lacquered iron, the thin, underexposed image reads as a positive — an ambrotype or a tintype.
6. On clear glass left unbacked, the same plate serves instead as a negative, ready to print multiple paper positives.
About the Process
Character
Extraordinary fine detail and tonal range. Each ambrotype or tintype is a unique object, like a daguerreotype, unless made deliberately as a printing negative — with characteristic deep shadows, softly luminous highlights, and plates that were often hand-tinted afterward.
HANDLING
The most hazardous process here to reconstruct faithfully. Ether is highly flammable, silver nitrate stains and burns skin, and the historical fixer was potassium cyanide — lethal. Modern practitioners substitute sodium thiosulfate for fixing and work under serious ventilation and fire precautions throughout.
LEGACY
The strongest living revival of the five. A genuine community of working "collodion artists" runs studios, festival tintype booths, and wedding-portrait sessions today, drawn to a look digital photography can't fake. It's the process most likely to sustain a paid workshop practice, and the one most collectors and photo-history museums treat as a hands-on craft rather than a museum-only relic.