Calotype Process
British · Calotype / Salt Print 1841–1860
The daguerreotype was sharper and the calotype won anyway, because it had a negative. Every photograph made since, on film, descends from Talbot's paper process rather than from Daguerre's plate.
Origin
William Henry Fox Talbot developed photogenic drawing from 1834 and the calotype proper by 1841, working in parallel with and slightly behind Daguerre. He patented it aggressively, which suppressed its commercial adoption in England while it flourished in Scotland — Hill and Adamson made several thousand calotype portraits in Edinburgh in the 1840s — and in France. His Pencil of Nature, issued from 1844, was the first commercially published book illustrated with photographs.
Technique
Writing paper is brushed with silver nitrate and potassium iodide, then sensitised with gallo-nitrate of silver immediately before use. Exposure produces a latent image, developed chemically rather than by prolonged exposure, which is Talbot's decisive contribution: it cut exposure times enormously. The resulting paper negative is waxed to increase translucency and contact-printed onto salted paper to make positives, and any number of prints can be made from one negative.
The palette
Warm and soft, with the paper fibre visible in the image. Salt prints are a rich reddish or purplish brown, the colour of finely divided silver formed directly by light rather than by a developer, and they lack the hard blacks of later processes. Because the negative is paper, its texture is printed along with the image, giving a broad, granular, slightly diffused result — closer to a drawing than to the daguerreotype's microscopic precision.
Legacy
The negative-positive principle is the foundation of all photography until digital capture. Aesthetically the calotype was also the first process claimed for art rather than for record: its softness was defended as expressive, and that argument runs directly to Pictorialism half a century later. Salt prints fade badly, and many surviving examples are considerably weaker than when made.
Palette
The colours reconstructed for this artist, with the reasoning behind each.
Pigments used: Silver