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"Eric Keller is one of the most knowledgeable and passionate people I know in the field of fine art photography, and he has the rare talent of being able to combine these attributes with a smart business sense. He is conscientious and honest, and a pleasure to do to business with." Robin Hurley, St. Ann's Press






This list of commonly used photographic terms and processes is designed to assist you in your education about the history of photography. .Scroll down to review a list of recommended reading; very helpful for anyone interested in studying or collecting fine art photography.

Albumen Print - Introduced in 1850 by L.D. Blanquart-Evrard. The most common photographic print in the 19th century. Made by coating the paper with the egg albumen and sodium chloride, producing a rich sepia color and slightly glossy surface. These prints were often toned with gold chloride to subdue the sepia tone and improve the permanence of the photograph.

Ambrotype - This process was in general use from 1855 to around 1865. It is a positive, silver image on glass. Due to the fragility of the glass backing ambrotypes were put in cases similar to those used for daguerreotypes. Although often confused with a daguerreotype, an ambrotype will always appear as a positive no matter the angle of view. A daguerreotype on the other hand will switch from a positive to a negative image depending upon the angle at which it is viewed.

Artist Proof - These photographs are printed especially for the artist and excluded from the numbering of a limited edition, but are exactly like the editioned prints in every other respect. Usually appears as "A.P."

Blind Stamp - An identification mark embossed onto the mount of a photograph, or in some cases, such as the photographs of Henri Cartier-Bresson, onto the photographic print itself.

Calotype/Talbotype - Invented in 1839 by William Henry Fox Talbot, this was the first practical process of photography. It was revolutionary at the time in that it allowed for making multiple positive prints of a single image. The calotype process was used until around 1850 when it became gradually superseded by the collodian process on albumen paper.

Chromogenic Print - Color print made from a color transparency or negative. The print material has at least three emulsion layers of silver salts. Each layer is sensitized to one of the three primary colors in the spectrum. During the first stage of development a silver image is formed on each layer. Dye couplers are then added which bond with the silver and form dyes of the appropriate colors in the emulsion layers.

Cibachrome Print - An extremely high-gloss paper manufactured by Ilfochrome and first introduced in 1963. A silver dye-bleach process that forms an image by selectively bleaching dyes already existing within the paper. Renowned as one of the most stable, longest-lasting of all color prints.

Collodion/Wet Plate - Invented by Frederick Scott Archer in 1848. A sheet or plate of glass was coated with collodion, made lightsensitive, exposed and developed, all before the emulsion dried. The finished negative was usually varnished to preserve and protect it. Collodian wet-plates were most often printed on albumen paper. This was the most commonly used process from the mid-1850s until the 1880s, when it was replaced by the gelatin dry plate process.

Collotype - A photomechanically printed image made from a photographic image. This process produced an extremely fine and delicate grain, and was favored by publishers who wanted a means of reproduction that emulated the appearance of an actual photograph.

Contact Print - A print that is the same size as the negative used to produce it. A contact print is made by placing a sheet of sensitized material in direct contact with the negative. Nearly all photographic images produced prior to the 1890s were contact prints. The process was also widely used by Edward Weston and others of the modern era.

Cyanotype - Sir John Herschel invented this process in 1840. Herschel was an astronomer and inventor who first used the terms "negative" and "positive" to describe the making of a photographic print. Among the earliest permanent processes, the name cyanotype refers not to the blue tonality of the prints, but rather to the use of ferrous cyanide in the emulsion. In the 1870s it became known as a "blueprint" and is still widely used to reproduce architectural plans.

Daguerreotype - This, the first published photographic process, was invented by Louis J. M. Daguerre in France in 1839. It soon became the most popular medium in the mid 19th century, producing a unique and permanent direct positive image on a copper plate without the use of a negative. The plate was exposed in the camera for as long as 20 minutes in daylight, which required the sitter to remain very still for long periods of time. The silver surface has a mirror-like shine and, being fragile, were often placed into a special viewing case; sizes vary but are measured from double whole plate (8 x 13 inches) to sixteenth plate (1 5/8 to 2 1/8 inches) with the sixth plate the most common (2 x 3 inches). The daguerreotype process was eventually replaced by the wet collodian process in the 1850s.

Dye Transfer - One of the most permanent and beautifully rendered of all color printing processes, this method required three separate sheets of negative film to be produced through red, green and blue filters. These separation negatives were then projected or contact-printed to make three matrices dyed in cyan, magenta and yellow dyes. Each matrice was then brought into registered contact with a sheet of transfer paper that absorbed the dye, producing a finished print made up of a combination of dye images. The film used to produce this very caustic process was discontinued in 1996.

Editioning - A limitation on the number of prints produced of a photograph from a single image. This number is set by the artist and noted on the photograph itself, usually appearing as a fraction, such as 1/25.

Ektacolor RC Print - Photographs produced from color negatives printed on paper coated with a resined plastic. The most commonly produced color print of the modern era.

Emulsion - The light-sensitive coating, consisting of silver-halide crystals suspended in a gelatin. Applied to photographic paper, plates and film, in which the final photographic image is suspended and protected. In albumen and collodion prints, the silver halides rested on the surface of these substances. With salt prints, platinum and palladium prints, the emulsion is absorbed into the paper itself.

Gelatin Silver Print - Introduced in the 1870s, this is the most common of all printing processes in which paper is coated with gelatin that contains light sensitive silver salts. This is the standard contemporary black and white print method used today and is also referred to as a silver gelatin print, or simply as a silver print.

Glass Plate - A transparent plate of glass was coated with an emulsion containing light sensitive silver salts, then placed in the camera and exposed. It was then immediately developed and later varnished to preserve and protect it. In the late 1890s when Edward S. Curtis began photography for The North American Indian he was using 14 x 17" glass plates. By the end of the project some thirty years later technology had progressed to the point where he could use 6 x 8" plates and still retain the desired quality and sharpness.

Halftone - A photomechanical reproduction process of a photograph made on a printing press. An original photographic image is re-photographed through a screen that transforms the continuous tones of the image into a series of dots, relative to the amount of darkness in the original. The new image is then transferred onto a printing plate. The amount of ink deposited onto the plate is determined by the density of the dot pattern. This process was sometimes used in Alfred Stieglitz's Camera Work.

Limited Edition - The stated number of prints of a particular photographic image in a particular size and format, as set by the photographer. It is understood that once this edition number has been set that the photographer will not produce any further prints of that stated nature from this particular negative.

Mount - A secondary support to which a photograph is attached. Contemporary mounts should be of the best quality stock and always acid-free to preserve the archival image.

Orotone/Goldtone/Curt-tone - A positive image printed on glass, often made from contact printing the original negative. In the case of Edward S. Curtis, the man who perfected this process, the positive plate was then backed with a mixture of gold dust and banana oil. Due to the fragile nature of the plate, these images were most often sold framed in ornate gilded frames produced especially for the Curtis Studio.

Photogravure - Invented in 1879, this is a photomechanical printing process which produces a hand-pulled gravure. It is perhaps the most beautiful ink processes used for reproducing photographs and was made popular by Edward S. Curtis' The North American Indian, as well as Alfred Stieglitz's Camera Work, and the fine art photography books of Karl Blossfeldt. The process starts with the photographer's glass plate negative. From that a glass plate positive is produced. The image is then acid-etched onto a copper plate. This plate is then inked by hand and used to produce prints, one per inking, on a hand-operated press. Due to the very laborious nature of photogravure printing it was later replaced in commercial use by the halftone plate. Recently however, a handful of contemporary artists have revived this difficult and beautiful process.

Platinum and Palladium Prints - This method of contact printing was used primarily from 1873 to around 1915, when as a result of World War I, platinum paper was replaced for the most part by palladium. A black and white printing process in which the image is formed of metallic platinum or palladium in the fibers of the paper (instead of an emulsion coating on the surface). The hand-coated images are known for their luminosity, extraordinary detail, beautifully rich tonal range, permanence and stability. Platinum and Palladium printing has enjoyed a revival in recent years as well.

Printing-Out Paper - A commercially manufactured paper that was quite popular in the 1880s and 1890s and continued to be produced until the 1920s. Coated with silver-chloride emulsions and designed to develop a print from a negative by using light alone, rather than chemistry. This process was favored by photographers in the early American West, as field prints could be produced to review their work without the need of a darkroom.

Recto - Often seen as "au recto"; when referring to the photographer's signature this term means that it appears on the front of the photographic print or mount.

Salt Print - A print produced by coating fine-quality writing paper with light-sensitive chemicals and sodium chloride. Most often found in varying shades of brown or sepia with a matte surface quality. This was the earliest form of a photographic positive paper and the most common print produced up until the invention of albumen in the 1850s.

Silver Print - A generic term referring to all prints made on paper coated with silver salts. (Also see Gelatin Silver Print)

Tintype/Ferrotype - Introduced in the mid 1850s, a printing process in which a thin sheet of iron was coated with black lacquer. The light-sensitive emulsion was then coated on the iron plate just before placing it into the camera for exposure. The plate was then developed, producing a very durable, efficient and inexpensive photograph that was small is size (approximately 2 x 3 inches). Used most often for portraiture and made popular in the 1850s by street photographers. Also commonly used during the Civil War and remained popular to around the turn of the century.

Type C Print - A color printing process made from a color negative or transparency which was replaced in 1958 by Ektacolor. Type C is an archaic term which is commonly used generically to identify an Ektacolor RC print, the most common color print made today.

Verso - Often seen as "au verso"; when referring to the photographer's signature this term means that it appears on the back of the photographic print or mount.

Vintage/Modern Prints - A relative term that describes a print that is made on or very near the time of the negative. A print made later from the original negative is a modern, or later print. The date of a print can often be determined by the paper on which it was printed, as well as the overall condition of the paper surface. Other factors to consider are the overall quality of printing, the presence or absence of a signature and/or stamp, and the source from which it was obtained. There are also many helpful tools, such as a black light which can assist in dating a print.


Recommended Reading:

Looking at Photographs: 100 Pictures from the Collection of The Museum of Modern Art, by John Szarkowski. New York: The Museum of Modern Art, 1973.

On Photography, by Susan Sontag. New York: Farrar, Straus, Giroux, 1977.

The Photograph Collector's Guide, by Lee Witkin and Barbara London. Boston: The New York Graphic Society, 1979.

The History of Photography: From 1839 to the Present Day, by Beaumont Newhall. 5th Revised Edition. New York: The Museum of Modern Art, 1982.

The Encyclopedia of Photography. New York: International Center of Photography/Crown Publishers, 1984.

Looking at Photographs: A Guide to Technical Terms, by Gordon Baldwin. Los Angeles: The J. Paul Getty Museum/British Museum Press, 1991.

An American Century of Photography: From Dry Plate to Digital, by Keith F. Davis. New York: The Hallmark Photographic Collection/Harry N. Abrams, 1999.

Authentication and Forgery Detection of Prints & Antique Photographs: Introduction to Methods, by David E. Rudd. Seattle: Cycleback Press, 2001.


Glossary of Terms Copyright © 2002-14 Eric J. Keller/Soulcatcher Studio. All rights reserved.
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