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Dead medium: Dead photographic processes
From: marks@ayla.avnet.co.uk (Mark Simpkins)
Source(s): The Focal Encyclopedia of Photography (2 Volumes) 1965 edition, 2nd reprint. Editorial Board: L.A. Mannheim, Daphne Buckmaster, Frederick Purves, P.C. Poynter, Norah Wilson, Paul Petzold, A. Kraszna-Krausz.

Brief notes from this fairly comprehensive encyclopedia, with possible avenues for further research. I realise some of this is not radically unknown, but it needs recording.

The term 'Photography' came from the Greek phos, photos, 'light,' and suffix graphos, 'writing'. The word was first suggested to William Henry Fox Talbot by Sir John Herschel in a letter dated 28th February 1839.

Obsolete printing processes. (((Note that the encyclopedia entry for this section suggests that these processes are prototypical rather than obsolete.))).

CALOTYPE or TALBOTYPE. Paper sponged over with or floated on solutions of silver iodide and potassium iodide. When partially dry, the excess potassium iodide was removed by bathing in distilled water. Paper was sensitized in a solution of silver nitrate, acetic acid and gallic acid. After printing a feeble image was brought up to the required strength by an application of a solution similar to the silver nitrate sensitizer. Talbotypes produced rich warm brown images.

FLUOROTYPE. Paper washed with solution containing 2 per cent potassium bromide and 1/4 per cent sodium fluoride in distilled water. Sensitized by floating in a solution of 15 per cent silver nitrate for two minutes. Very sensitive to light. The inventor claimed an image of a brightly lit scene could be obtained in the camera by an exposure of only half a minute. The image was feeble though, and had to be intensified by brushing over with a weak solution of sulphate of iron. Fixed with hypo and washed.

CYANOTYPE. Invented by Sir John Herschel in 1842. Blue print process, mostly used for copying drawings giving a white image on a blue background. Still in use (((at least at time of this 1965 edition))).

PELLET PROCESS. Variation of cyanotype, gives blue image on white background. Introduced by H. Pellet in 1878.

FERRO-GALLIC and FERRO-TANNIC PAPERS. Introduced by A. Poitevin in 1861. Image formation relied on similar action to cyanotype (the reduction of ferric salts by light). Image formed by combination of ferrous salts with gallic or tannic acid, yielding a deep purple or brown insoluble organic compound.

ALBUMEN PROCESS. Paper coated with egg white before sensitization by floating on a silver nitrate solution. Resultant prints were toned with gold chloride. Remained in use for the next thirty years, superseded by printing- out papers using collodion or gelatin as a vehicle for the sensitizing salts.

ARGENOTYPE. Invented by Herschel in 1842. A silver image produced by utilizing the action of light on ferric salts. Printed out in daylight.

KALLITYPE. Introduced by W.J.Nichol. Sensitizer was ferric oxalate, reducing to ferrous oxalate. Yielded warm sepia tones.

PALLADIOTYPE, PLATINOTYPE. The papers for these processes was purchased ready prepared ((( unlike the previous processes which were do-it-yourself.))). The final print consisted of a deposit of platinum or palladium on the paper support. Palladium was introduced during World War I when platinum was difficult to get. Both produce rich blacks unobtainable with silver. The image was permanent.

These papers were very sensitive to damp. Special precautions had to be taken when opening the tin in which they were sold to keep them dry. During printing the paper had to be protected by covering the back with a sheet of rubber. Out of use due to scarcity and high cost of materials.

URANIUM PRINTING. The action of light reduced uranyl nitrate to a viscous compound. Produced a brown image, unless silver nitrate was used in the development, which produced a grey image due to deposited silver.

POWDER PROCESSES. Several processes were popular for a time, especially on the Continent. Certain substances such as sugar, dextrine or gum, treated with potassium bichromate, lost their natural tackiness when exposed to light. A dark powder was dusted over an exposed plate (or paper). This powder would adhere in proportion to the degree of the action of the light on the hardening of the coating. Plumbago or graphite powder was used. The plate was protected with a collodion coating.

The same principle is still used, employing certain resins, in various photomechanical processes.

PIGMENT PRINTING; OZOBROME PROCESS. Poitevin made photographic prints on paper coated with gelatin mixed with colouring matter and sensitized with potassium bichromate in 1855. This led to the carbon printing process.

In 1905 Thomas Manly invented the ozobrome process which eliminated the use of bichromated paper; the pigment image was made direct from a bromide print as in present day carbo process.

ARTIGUE PROCESS. Invented by M. Artigue of Paris. Gum, mixed with any desired colour pigment and sensitized with potassium bichromate, was coated on paper or other support and after exposure under a negative was developed in a soup-like mixture of sawdust and water. Capable of producing very delicate results.

OIL PRINTING. Introduced in 1904 by Rawlins, based on early lithographic transfer procedures of much earlier date. Depended on the action of light on bichromated but unpigmented gelatin coated paper.

The bromoil process is based on this and is still used today by some pictorial photographers.

CHROMOTYPE. Described by Robert Hunt in 1843, a process by which either a positive or a negative could be obtained depending on the length of exposure, the latter presumably by solarization.

BREATH PRINTING. Discovered by Sir John Herschel. Latent images could be prepared which could only be seen when breathed on or subjected to a moist atmosphere.

Paper was coated with the dissolved precipitate formed under certain conditions by the addition of silver nitrate to ferro-tartaric acid. Printed under a negative in sunlight the paper so prepared would, by the right exposure, be impressed with a latent image which was not visible unless breathed on or subjected to a light aqueous vapour, when it acquired an extraordinary intensity.

DIAZOTYPE. Designed in 1891 for printing photographically onto fabrics on which a range of colours could be produced. Prints could be made on paper but the colours were dull and whites impure. The term is nowadays generally applied to a number of similar processes.

PINATYPE. A transparency was made on a soft emulsion of the lantern plate variety and developed in a tanning developer. The "printing plate" so obtained was bated for about two minutes in an engraving black or photographic brown pinatype dye. The dye was held in suspension by the gelatin in direct proportion to the extent to which it had been hardened by light action during printing. The plate so charged with dye was then washed free of the surplus dye and finally brought in contact with a sheet of paper coated with plain gelatin. The two were squeegeed together and left for several minutes, when the dye in the plate was transferred to the virgin gelatin. When separated, the gelatin bore the dye image. Any number of prints could be made by dyeing-up the printing plate and repeating the imbition process.

WOTHLYTYPE. A printing-out paper invented by J. Wothly of Aachen, 1864. The paper coated with collodion containing uranium and silver nitrate, was considerably more sensitive than the albumen paper then in general use, but the claim for permanence, due to the uranium, was not fulfilled, and after a couple of years the Wothlytype was abandoned.

Mark Simpkins marks@ayla.avnet.co.uk

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