Glossary of processing terms

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A generic term referring to processes employing albumen, a pure form of the white of an egg, as a binder for the light-sensitive silver salts.

It was used to make either positives or negatives on paper or glass.

See Thomas Sutton, Dictionary of Photography, (London: Sampson Low, 1858), p. 12.

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The albumen on glass process was used to make negatives or positives until it was largely superseded by the collodion process in 1851.

For an account see Thomas Sutton, Dictionary of Photography, (London: Sampson Low, 1858), p. 17.

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The albumen on paper process was widely used throughout the second half of the 19th century as the principal process for photographic printing by both amateur and commercial photographers.

It was toned with chloride of gold which imparted a characteristic purple-brown colour. The process was occasionally used to make paper negatives.

For an account see Thomas Sutton, Dictionary of Photography, (London: Sampson Low, 1858), p. 14.

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Many types of object were exhibited, including cameras, lenses, stands, stereoscopic viewers and every kind of paraphernalia necessary to photography.

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Hippolyte Bayard developed a method for making direct positives on iodised paper in the Spring of 1839.

The process, exposing a silver chloride paper to light, then immersing it in a potassium iodide solution, was essentially a wet-paper calotype process and produced a direct positive by bleaching.

For an account of this process see J.M. Eder, History of Photography, (New York: Columbia University Press, 1945), reprinted (New York: Dover Publications, 1972), pp. 334-335.

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An unspecified variant for making prints, introduced by Robert Bingham most likely for use in his reproductions of paintings and works of art, for which he was well-known.

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A process for making negatives on paper in which the latent image was made visible by chemical development. The process was disclosed to the public by W H F Talbot on 10 June 1841.

The essentials of the process remained at the core of numerous variants introduced over the next twenty-five years.

Strictly speaking, the calotype refers to the process for making a camera negative , but is often mistakenly used to identify prints.

See Thomas Sutton, Dictionary of Photography, (London: Sampson Low, 1858), pp. 48-54.

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A generic term referring to processes for making positives on paper employing chromated gelatine mixed with a pigment to create a light sensitive emulsion.

A number of variations were introduced, but central to them all was the use of pigmented colours, and their resistance to fading.

For details of its introduction see J.M. Eder, History of Photography, (New York: Columbia University Press, 1945), reprinted (New York: Dover Publications, 1972), Chapter 79.

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The Chromatype process on paper invented by Robert Hunt was capable of making either a negative or, with a longer exposure, a direct positive.

The insensitivity of the process to light meant that it could not be used to make camera negatives.

For an account of this process see Robert Hunt, Researches on Light (London: Longman, Brown Green and Longmans, 1844), reprinted (New York: Arno, 1973), p. 150.

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One of the printing-out processes invented by Herschel in 1842, using the action of light on organic salts of ('ferric') iron.

The resulting feeble image (of 'ferrous' salt) is rendered permanent by a solution of gold chloride, which deposits as purple gold metal (in the 'colloidal' or nanoparticle state).

It is a close relative of Herschel's cyanotype and argentotype processes, but was little used due to expense.

For an account of this process see Mike Ware, 'Prints of Gold: The Chrysotype Process Re-invented', Scottish Photography Bulletin, No.1, 1991, pp. 6-8.

See this source online at http://www.mikeware.demon.co.uk/gold.html.

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A generic term for two different processes for making either negatives or direct positives on paper.

When exposed and washed with a solution of silver nitrate, the salts of cobalt change colour to brown and the resulting negative may be re-exposed to light to form a direct positive.

Cobalt prints may also be used as a generic name for a variant of Calotype, in which cobalt was used to speed the exposure time or to conserve silver nitrate.

For an account of this process see Robert Hunt, Researches on Light, (London: Longman, Brown Green and Longmans, 1844), p. 160.

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A popular variant of the collodion process used to make negatives on glass. Many variations of this dry collodion process existed, all utilising a final layer of albumen emulsion to protect the primary collodion layer.

For an account of this process see J. Towler, The Silver Sunbeam, (New York: Joseph Ladd, 1864), reprinted (New York: Morgan & Morgan, 1969).

See this source online at http://albumen.stanford.edu/library/monographs/sunbeam/toc.html.

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A variant of the collodio-albumen dry process for making negatives on glass.

As its name suggests the process employed honey as a preservative.

For an account of this process see J. Towler, The Silver Sunbeam, (New York: Joseph Ladd, 1864), reprinted (New York: Morgan & Morgan, 1969).

See this source online at http://albumen.stanford.edu/library/monographs/sunbeam/toc.html.

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A variant of the collodio-albumen process for making dry collodion negatives on glass, popularised by Hill Norris.

For an account of this process see J. Towler, The Silver Sunbeam, (New York:Joseph Ladd, 1864), reprinted (New York: Morgan & Morgan, 1969).

See this work online at http://albumen.stanford.edu/library/monographs/sunbeam/toc.html.

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A variant of the collodio-albumen dry collodion process for making negatives on glass. The addition of tannin changed the sensitivity and tonal variation in the negative.

For an account of this process see J. Towler, The Silver Sunbeam, (New York:Joseph Ladd, 1864), reprinted (New York: Morgan & Morgan, 1969).

See this work online at http://albumen.stanford.edu/library/monographs/sunbeam/toc.html.

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A generic term for any collodion process that used honey as a preservative to render the collodion 'dry', by slowing the rate of evaporation from the plate.

For an account of this process see T.F. Hardwich, A Manual of Photographic Chemistry, (London: John Churchill & Sons, 1864), seventh edition, p. 329.

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A variant dry collodion process for making negatives on glass in which malt was used as a preservative.

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This is the generic name for the process used by Hill Norris to make dry collodion negatives on glass. For an account of this process see J. Towler, The Silver Sunbeam, (New York:Joseph Ladd, 1864), reprinted (New York: Morgan & Morgan, 1969) p. 244.

See this source online at http://albumen.stanford.edu/library/monographs/sunbeam/toc.html.

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The Collodio-tannin process is a variant used for making dry collodion negatives on glass.

Different strength tannin baths were used to vary the tonality and sensitivity of the negatives.

For an account of this process see J. Towler, The Silver Sunbeam, (New York: Joseph Ladd, 1864), reprinted (New York: Morgan & Morgan, 1969), p. 245.

See this source online at http://albumen.stanford.edu/library/monographs/sunbeam/toc.html.

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A variant of the collodio-tannin process.

For an account of this process see J. Towler, The Silver Sunbeam, (New York: Joseph Ladd, 1864), reprinted (New York: Morgan & Morgan, 1969), p. 248.

See this source online at http://albumen.stanford.edu/library/monographs/sunbeam/toc.html.

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A variant of the collodio-tannin process.

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A generic term for any process using collodion as a binder for the light-sensitive silver salts.

Collodion lay at the heart of many negative and positive processes on glass and paper following its introduction in 1851.

Various adaptations were devised, and broadly fall into two general categories; wet collodion and dry collodion.

For an account of this process see Thomas Sutton, Dictionary of Photography, (London: Sampson Low, 1858), pp. 121-140.

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Lafon de Camarsac published this positive collodion process in 1855, claiming that the images were made permanant and registered a deeper black by burning them in on an enamel base.

For an account of this process see J.M. Eder, History of Photography, (New York: Columbia University Press, 1945), reprinted (New York: Dover Publications, 1972), p. 566.

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Collodion processes were most commonly coated on glass and applied to the making of either negatives or positives on this surface.

For an account see Thomas Sutton, Dictionary of Photography, (London: Sampson Low, 1858), pp. 121-140.

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This process created a direct positive on japanned leather by transferring the collodion to the blackened surface, or by placing the japanned leather directly in the camera.

For an account of this process see J. Towler, The Silver Sunbeam, (New York: Joseph Ladd, 1864), reprinted (New York: Morgan & Morgan, 1969) p. 150.

See this source online at http://albumen.stanford.edu/library/monographs/sunbeam/toc.html.

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Collodion was occasionally coated on paper instead of glass to make negatives in the manner of calotypes. For an account see Thomas Sutton, Dictionary of Photography, (London: Sampson Low, 1858), p. 139.

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This term has been used for any positive made with a collodion process, when the base material of that positive was not listed in the exhibition catalogue.

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The Cyanotype process can be used to make either negatives or positives on paper.

It was most commonly used for making images by direct contact with objects such as leaves and feathers, or for making prints from negatives.

The inexpensive nature of the sensitising solution and the relative simplicity of its operation made it popular among amateurs following its invention in 1842.

For an account of this process see Mike Ware, Cyanotype, (London: Science Museum, 1999).

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A direct positive process in which a silvered copper plate was made sensitive to light by fuming in iodine vapour. After exposure the latent image was made visible by the fumes of warmed mercury.

Invented by L.J.M. Daguerre, it was revealed to the public 19 August 1839, and remained immensely popular through the 1850s, especially for use by professional portrait photographers.

For an account of this process see M. Susan Barger and W.B. White The Daguerreotype, (Baltimore: Johns Hopkins University Press, 1991).

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A variant of the carbon process for making positives on paper, patented by Fargier in 1860.

He introduced an innovative method of transferring the chromated pigment coating to an alternative base prior to printing.

For an account of this process see J.M. Eder, History of Photography, (New York: Columbia University Press, 1945), reprinted (New York: Dover Publications, 1972), Chapter 79, p. 557.

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Fothergill introduced a modification of the collodio-albumen process for making dry collodion negatives on glass. In this variant, the plate is sensitised only once.

For working details of this process see J. Towler, The Silver Sunbeam, (New York: Joseph Ladd, 1864), reprinted (New York: Morgan & Morgan, 1969) p. 242.

See this source online at http://albumen.stanford.edu/library/monographs/sunbeam/toc.html.

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A generic name for photogravure in France. Also a photomechanical process that employs light sensitive asphaltum to create a resist for directly etching metal or pewter plates for printing positives on paper.

The process was first discovered by Nicéphore Niépce, and perfected in many variants throughout the 1800's.

For an account of this process see J.M. Eder, History of Photography, (New York: Columbia University Press, 1945), reprinted (New York: Dover Publications, 1972) p. 591.

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A variant dry collodion process for making negatives on glass in which a collodio-meta-gelatine combination was used as a preservative. Hill Norris patented his dry collodion process in September 1856.

For an account of this process see J. Towler, The Silver Sunbeam, (New York: Joseph Ladd, 1864), reprinted (New York: Morgan & Morgan, 1969) p. 244.

See this source online at http://albumen.stanford.edu/library/monographs/sunbeam/toc.html.

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A generic term used in this instance for an image made in camera by means of any photographic process, when that process was not listed in the exhibition catalogue.

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A generic term describing a negative made on a glass surface with any photographic process.

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A generic term descirbing a negative made on a paper surface with any photographic process.

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Refers to a missing entry in the original exhibition catalogue.

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A variant of the collodio-honey dry process for making negatives on glass.

Oxymel was a combination of honey and vinegar, used to preserve the sensitised collodion plate.

The process was devised by John Dillwyn Llewellyn and introduced in 1856.

For an account see T.F. Hardwich, A Manual of Photographic Chemistry, (London: John Churchill & Sons, 1864), seventh edition, p. 329.

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A photomechanical process patented and by Paul Pretsch that involved the use of Talbot's method of photographic engraving followed by the use of electricity to etch the copper plates.

Talbot's claims were upheld in court, where it was ruled that the photogalvanograph was essentially photographic engraving.

For an account see T.F. Hardwich, A Manual of Photographic Chemistry, (London: John Churchill & Sons, 1864), seventh edition, p. 368.

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The process announced by W.H.F. Talbot in 1839 in which silver salts coated on paper were darkened through the action of light.

It was used to make camera negatives and negatives by direct contact with objects such as leaves and lace. The same process was used to make prints by direct contact with these negatives. It was superseded by the calotype process.

For an account of the history of this process see L J Schaaf, Out of the Shadows, (New Haven & London: Yale University Press, 1992).

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Photographic engraving, an early form of photogravure, was a photomechanical process patented by Talbot in 1852.

It was a process employing bichromates and gelatine to form the image on metal plates prior to etching and printing the final image in ink.

For an account of this process, see Larry Schaaf, Sun Pictures: Talbot and Photogravure, (New York: Hans P. Kraus Jr, 2003).

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A generic term for any photomechanical process that used a photographic emulsion to produce a planographic plate that could then be inked to create a positive on paper.

The earliest photolithographs were made by Nicéphore Niépce, using a light-sensitive resist formed by Bitumen of Judea dissolved in lavendar oil, on stone, glass, pewter and silver plates.

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Joubert's patented process for making direct positive prints from positives on glass or paper.

The process utilised the tanning action of potassium dichromates, and the image was formed by direct deposit of finely powdered pigment on the plate.

For an account of this process see the entry for 'collotype' in Luis Nadeau, Encyclopedia of Printing, Photographic, and Photomechanical Processes, (New Brunswick: 1994), volume 1, p. 73.

See also Wolfgang Baier, Geschichte der Fotografie, (Munich: Schirmer Mosel, 1977), p. 203.

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A photomechanical process in which the photographic image is transferred to a zinc plate for printing. The use of zinc allowed the surface to be slightly etched with nitric acid to enhance the quality of the resulting image.

For an account see T.F. Hardwich, A Manual of Photographic Chemistry, (London: John Churchill & Sons, 1864), seventh edition, p. 368.

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Poitevin's process was one of the earliest and most successful applications of chromated pigment printing, which he introduced in 1855.

For an account of this process see J.M. Eder, History of Photography, (New York: Columbia University Press, 1945), reprinted (New York: Dover Publications, 1972), Chapter 79, pp. 553-556.

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A generic term referring to images made from a photographic negative.

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A generic term which embraced a variety of different, but unspecified processes. Ambrotypes, lantern, and stereoscopic slides were all positives on glass.

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A process in which the photographic image was printed on linen rather than paper.

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A generic term referring to a photographic print.

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A generic term referring to three dimensional photographs or the apparatus used to view them.

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A variant of the carbon process distinguished by the use of single and double transfer stages which greatly improved the resulting image.

Swan took a British patent for this process in February 1864.

For an account of this process see J.M. Eder, History of Photography, (New York: Columbia University Press, 1945), reprinted (New York: Dover Publications, 1972), Chapter 79, p. 558.

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An alternative name for the Calotype process and most frequently used by Talbot's friends and supporters, though never by Talbot himself.

This collodio-albumen process was one of the earliest methods of making dry collodion negatives.

The sensitised albumen layer that was added to the plate after the sensitised collodion layer rendered the plate slower, but much more convenient to use.

For an account of this process see J. Towler, The Silver Sunbeam, (New York: Joseph Ladd, 1864), reprinted (New York: Morgan & Morgan, 1969), p. 237.

See this source online at http://albumen.stanford.edu/library/monographs/sunbeam/toc.html.

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A variant of Le Gray's wax-paper process, it employed wax dissolved in turpentine to coat the paper negative prior to sensitisation and claimed superior results.

It was introduced to Britain by Rev. J. Lawson Sisson in 1858.

For an account see, The Photographic News, 19 August 1859, pp. 277-278. See also J. Towler, The Silver Sunbeam, (New York: Joseph Ladd, 1864), reprinted (New York: Morgan & Morgan, 1969) p. 179.

See this source online at http://albumen.stanford.edu/library/monographs/sunbeam/toc.html.

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Uranium salts may be used to make positive or negative images on paper.

They were also employed to vary the Collodion wet process, as in the case of the Wothlytype.

For an account see T.F. Hardwich, A Manual of Photographic Chemistry, (London: John Churchill & Sons, 1864), seventh edition, p. 363.

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A successful and widely used process for making paper negatives, it differs from the calotype in its use of prewaxed paper prior to sensitisation and exposure.

It was introduced by Gustav Le Gray in 1851.

For an account of this process see Thomas Sutton, Dictionary of Photography, (London: Sampson Low, 1858), pp. 54-56.

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A method of making collodion positives on paper using salts of silver and uranium, the Wothlytype was patented by Jakob Wothly in 1864.

For an account see http://www.mspong.org/cyclopedia/photography.html.

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