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Ambrotype (1855–70): Process that creates a positive image on glass using collodion. It was invented in the United States in 1854 by James Ambrose Cutting and used until 1880.

Analog (image): In photography, a portrayal of reality obtained by imprinting light on a sensitive plate, one image at a time. In television and video, the result of a graphical analysis that is represented via an electronic beam sweeping a screen, allowing black-and-white or colour masses to be reproduced on a cathode-ray screen.

Backlit: Said of a photograph taken toward the light source, rather away from it, as is sometimes recommended to beginners.

Autochrome: The first colour process, invented by the Lumière brothers. It was a great commercial success between 1907 and 1930. A glass plate is covered with a layer of potato starch dyed violet blue, orange-red, and green, and then with a black-and-white emulsion. With exposure, the silver grains mask some of the grains of coloured starch to a greater or lesser degree, and the colours are then restored through an additive method. Once developed, the image obtained is a positive visible by transmission.

Calotype (1840–55): Process patented by William Henry Fox Talbot in 1841 and used until the mid-1850s. An image is produced by exposure in a darkroom onto paper sensitized with silver nitrate and potassium iodide solutions and developing with silver gallonitrate. The great advantage of this process over the daguerreotype was the ability to print multiple positives from a single negative.

Camera obscura: Precursor of the darkroom. At first, it consisted of a room in which viewers could see images projected thanks to natural light entering through a small (pinhole-sized) aperture. Later, this installation was transformed into a portable box with an opening, a lens, and a screen. This is the same principle as that used in a camera.

Chromogenic development print: Process invented by the Eastman Kodak Company in 1935 to make colour negatives and slides; it is still in use today. Positive colour images are composed of organic dyes in the three primary colours (cyan, magenta, and yellow) fixed to the paper in layers of binder.

Collage: Image produced by combining photographs, drawings, and various materials glued onto a surface.

Contrast: Relative value of the lightest and darkest parts of an image.

Copygraphy: Art practice consisting of diverting photocopiers from their usual purpose to creative ends. “Copy art” refers to a group of ways of using photocopiers expressively, whatever their type (thermographic, chemical, digital, or analog).

Colour photography: In the nineteenth century, Ducos du Hauron and Gabriel Lippman, taking completely different paths, produced the first colour photographs. It was not until the twentieth century that the first commercial colour processes were invented.

Computer graphics: All computer-generated graphical representations in point, vectorial, two-dimensional, or three-dimensional mode.

Contact print: Print obtained by placing the negative in direct contact with the sensitive surface. A contact print is the same size as the corresponding negative.

Cyanotype: Invented by Englishman John Herschel in 1842, the cyanotype made it possible to produce a positive print directly through the use of potassium ferricyanide to sensitize the paper. These permanent, inexpensive prints, also called blueprints, are still used in architecture today.

Daguerreotype (1839–60): Positive image obtained on a sheet of silver plated onto copper in a process invented by Louis-Jacques Mandé Daguerre and Nicéphore Niepce, and fixed by amalgam. From 1839 to 1860, it was the most popular form of photograph. The images obtained with this process showed very fine detail, but they were also very fragile. As a precaution, they were displayed under glass, framed, or in a protective case.

Digital: Said of any form of electronic recording (image or audio) in which representation of data or of physical size is based on binary elements (1 or 0). As opposed to analog.

Environment: In contemporary art, describes the attitude of artists who want to free themselves from the limitations of traditional media to extend the creative act to the surrounding space. These artists seek to create a relationship between the work of art and the real world.

Ferrotype: Process invented by Victor M. Griswold in 1856 and used almost exclusively to produce inexpensive portraits. The positive image is obtained by exposing a black-varnished metal plate coated with a collodion emulsion.

: Method for creating a three-dimensional image. A laser beam is divided into two parts. One is reflected by an object and interferes with the other, which comes directly from the laser. The interference pattern created when the two beams meet is recorded on a photographic plate, which, when lit by white light or laser, gives a three-dimensional image.

Illustrated postcard: Thanks to postal regulations in the early twentieth century, illustrated postcards immediately became very popular. These standard format (8.7 x 13.6 cm) postcards were printed with different processes, from collotype to half-tone. Postcards remained one of the richest fields for photography throughout the twentieth century.

In situ: Latin expression meaning “in the place.” It is used to designate artworks created in relation to a specific site.

Installation: In contemporary art, production that tends to substitute for the notion of an artwork all of the elements of a work in relation to the site where it is exhibited or to its environment.

Kirlian: Instrument that makes visible, through electrical impulses, the energy aura of substances. It should be noted that this apparatus is not the prerogative of the occult; it is used mainly for therapeutic purposes. A careful study of the aura around a body apparently reveals the presence of disease well before symptoms are manifested.

Multimedia: This term appeared in the late 1980s, when CD-ROMs were developed. At the time it designated applications that, thanks to the storage capacity of CDs and increased computer memory, could generate, use, or drive different media simultaneously: music, audio, images, video, interfaces, human-machine, interactivity. Today, the word “multimedia” is used to designate any application using or being used to operate at least one specific medium.

Negative: Photographic image in which the values of the subject are inverted; this is the normal result of development followed by fixing.

Perspective: The concept of perspective was born during the Renaissance, when natural vision was for the first time reconstructed by artifices of representation. Perspective is a geometric method for representing three-dimensional space in two dimensions.

Photoengraving: Process used since 1852 to produce multiple prints from slides. Today, photoengraving is still used for high-quality monochrome reproductions.

Photogenic drawing: William Henry Fox Talbot was very knowledgeable about silver salts, and in 1834 he produced the first negatives on paper impregnated with silver nitrate fixed in a salt solution. These images were the result of exposure to light of objects such as leaves and blades of grass placed directly on the paper.

Photograph (to): The action of capturing an image with a camera.

Photomontage: A process of assembling cut-out photographic elements to obtain a composite image that is not related to reality.

Positive: Photographic print in which the light and dark parts correspond to those of the subject portrayed.

Print: Image on paper obtained through photographic processes.

Silver gelatin print (1874–....): Process used since 1880, invented through industrial research. The negatives are sensitized in the factory and sold ready to use. At first, glass plates were used, and then flexible backings (cellulose and, after 1960, polyester). This process is still used in black-and-white photography.

Stereoscopy: Pair of photographic views taken beside one another from very slightly different angles and placed side by side. When they are viewed separately by each eye through a stereoscopic or binocular viewer, the two images seem to merge to give the illusion of three dimensions.

Toning: Chemical processing used to change the tonality or improve the stability of a photograph. In the case of silver images, the silver is combined with another compound, such as gold, platinum, selenium, or sulphur.

Video art: Art form that developed through the use of electronic media. Its principal tool is the camcorder, with which moving images and sounds are recorded.


Glossaire des procédés photographiques. Ottawa: Musée des beaux-arts du Canada, 1994.

Breuille, J.P., Guillemot, M., and Chiesa, P. Dictionnaire mondial de la photographie des origines à nos jours. Paris: Larousse, 2001.

Frizot, Michel, et al. Nouvelle histoire de la photographie. Paris: Bordas, 1994.

Poissant, Louise, et al. Dictionnaire des arts médiatiques. Sainte-Foy: Presses de l'Université du Québec, 1997.

Rosenblum, Naomi. Une histoire mondiale de la photographie, New York: Abbeville, 1998.


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