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Albumen prints: The first paper prints (salted paper prints) were made from paper floated on a solution of sodium chloride (table salt) and sensitized with silver nitrate. Because the image on such papers was formed on the fibres below the paper's surface, it did not have the clarity of a daguerreotype. Treating the surface of the paper with an albumen mixture made from egg white prevented the silver salts from sinking into the paper, increased the reflectivity of the paper and made the print appear to have greater definition. These papers were used from the mid-1850s until the 1890s. At the height of their use, so much albumen paper was being prepared that recipes were published for dishes that called for only egg yolks.
Ambrotype: The wet collodion process was much cheaper than the daguerreotype, and permitted the printing of multiple copies from one negative. But the cachet of the daguerreotype and the case in which it was contained was replicated in the wet-plate system by binding a thin negative with a black backing (which reversed the image tones) and placing it in a case like that of the daguerreotype. Ambrotypes were produced primarily in the 1850s and 1860s.
Artificial lighting: The earliest photography generally required long exposures in bright sunlight. Without it, photographers could not make images and therefore could not make money. Winter, when the sun is weak, overcast or rainy days, and evenings were all non-remunerative periods. Chemical developments through the 19th and 20th centuries permitted photographers to take images with shorter and shorter exposures, as the emulsions became more and more sensitive. However, artificial lighting was (and still is) necessary in many low-light situations. Beginning in the 1840s, arc lights (powered by series of wet-cell batteries) and gas-fired lime lights were used in some studios. When the incandescent lamp was introduced, some photographers installed their own generators. Magnesium flash powder was used for non-studio work until the 1910s; the flash bulb was introduced in the 1920s and used until replaced by speed lights in the 1960s; and portable electric lighting designed for many different conditions and situations was developed over the 20th century, in part as a response to the needs of the film industry.
Cabinet: Larger than the carte-de-visite (about 4" x 6"), cabinet photographs were popular from the late 1860s to the 1890s. Like the carte-de-visite, the cabinet often bore the photographer's name. Both cartes and cabinets were often collected in albums that had been manufactured to hold these sizes of photographs.
Calotype (or talbotype) process: when William Henry Fox Talbot, inventor of the negative-positive photographic system, began his work, he used paper negatives. After a number of improvements, the process was made publicly available as the calotype process. It was not widely used in Canada because it did not give the definition and clarity provided by the daguerreotype; on the other hand, the paper fibres in the negative gave the finished print a chiaroscuro (contrast of light and dark) effect.
Camera: A photographic camera is a light-tight box with a lens at one end and a light sensitive surface (a plate or film) at the other, on which the light coming through the lens is focussed. In the case of pinhole cameras, the lens is dispensed with and replaced by a tiny hole; this sort of camera is wholly impractical for portraiture or exposures under several minutes in duration.
Carte-de-visite: Roughly the size of a visiting card (about 2" x 3"), this size was very popular from the 1860s to the 1880s. The albumen print was glued to a piece of lightweight card, which usually bore the photographer's name.
Celluloid negatives: Until the 1880s most photographic negatives (with the exception of calotypes) were made on glass plates. The first celluloid negatives were made from casting a viscous solution of pyroxyline with varying proportions of several other chemicals in order to create a thin film, which was then coated with a layer of light-sensitive silver halide, and packaged in a light-tight container until used by the photographer. Commonly known as nitrate film, it was highly flammable and subject to chemical deterioration but, because of its mechanical strength was used until the early 1950s. By the first decade of the 20th century, various acetate films -- which were termed "safety" films because they did not burn as well -- had started to replace nitrate. But because acetate films could lose their chemical and physical integrity through a leaching out of acetic acid, they, in turn, were replaced in the1960s by more stable plastics such as mylar, which are still in use.
Colour: The first photographic systems were all monochromatic, or "black and white." Photographers would retouch their images with colours, for example reddening cheeks and making jewellery appear to be made of gold. Although experiments to create natural colour photographs started in the 1840s, the first practical systems were not developed until the 1860s and 1870s. These required three separate negatives and special filters, and were first used in the printing industry in the 1890s. Subsequent commercial colour photography systems generally used screens to separate the colours; some of these required the screen both in order to take and to view the image. All of these systems produced transparencies, which had to be held up to the light in order to be seen. The major revolution was the Kodachrome colour transparency of 1936. It was the first integral tripack film; this technology, which underlies all current colour transparencies, uses three different dye layers and two filter layers on one film base, and allows photographers to take photographs without any external paraphernalia. However, the processing was initially so complex that Eastman Kodak was for many years the only firm to undertake it. Kodachrome provided sharper, brighter images with more saturated colour than had the earlier screen systems.
Colour print materials were not as quickly commercialized. Until the early 1940s, most colour prints were made by printing negatives on three separate sheets of special paper, which were then laid down in registration (layers). By the late 1940s, relatively inexpensive commercial colour print materials and colour negatives were available; but colour prints came into their own only in the late 1960s. Unfortunately, many colour prints suffered fading or colour shifting (when the various colour layers change colour unequally) until more stable materials became available in the 1980s.
Daguerreotype: The first widely used form of photography, used between 1839 and the 1860s. A daguerreotype is made on a sheet of silvered copper, which is sensitized with a halide (usually iodine) in a special fuming box, exposed in the camera and then developed using heated mercury. A gold toning solution ensures permanence. Because the image surface is very fragile, the daguerreotype type is sealed behind a glass protective cover in a small case. A daguerreotype is a unique image.
Enlarger: In order to make a print larger than the size of the negative, it is necessary to enlarge the image on the negative. When, as was the case during much of the 19th century, negatives are dimensionally large (8" x 10", for example), easily viewed contact prints can be made by placing the negative on light-sensitive paper, exposing it under light, and developing and fixing the paper in order to create a permanent print. When the negatives are relatively small (as with the roll-film cameras introduced at the end of the 19th century), viewable prints can be made with the enlarger. The introduction of bromide papers in the 1880s made enlarging easier and faster than with the older albumen papers. The enlarger is usually vertical in structure and, from the top, consists of a lamp, a carrier for the negative, a lens and a baseboard. The lamp projects an image of the negative through the lens and onto photographic paper, which is held in place on the baseboard.
Negative/positive system: This is the system commonly used in photography, in which a negative image, the lights and shadows of a scene being reversed, is created on film placed in the camera and exposed to light. After developing and fixing, the negative can be used to create a positive image on a light-sensitive surface (usually a piece of photographic paper).
Photography: An image-making system that involves a taking mechanism (a camera), a light-sensitive surface on which the image is captured (a plate or film), a means of focussing the image on the plate or film (a lens), chemistry to develop and fix the latent image on the plate or film, and a printing system (often using an enlarger) which gives a positive image from the negative, usually printed on light-sensitive paper that is developed and fixed after exposure.
Silver gelatin negatives: Instead of using collodion to carry the light-sensitive silver salts, an emulsion of gelatin was coated on the negative (which could be glass or celluloid film). The great advantages of gelatin were that plates and films could be factory made, assuring greater consistency and quality, and they did not have to be developed immediately after exposure. They also were generally faster, meaning more light-sensitive, than collodion negatives.
Silver gelatin prints: Beginning in the 1870s, gelatin began to replace albumen in preparing the paper print. Bromide developing paper (a paper coated with a gelatin emulsion containing light-sensitive silver bromide, which after exposure was developed and fixed) became widely popular in the mid 1880s. It was much more sensitive than albumen paper, which meant that enlargements could be easily made from small negatives. This helped promote the development of small cameras, which in turn helped popularize photography as a pastime. Bromide, and the related chlorobromide and chloride papers, were the mainstay of photography throughout the 20th century and are still manufactured.
Stereoscopic photographs: The stereo photograph consists of two images taken by a camera with two lenses, situated about the same distance apart as an average person's eyes, and mounted on a piece of card. When looked at through a stereo viewer, the images combine to give a three-dimensional aspect to the scene. Very popular from the 1860s through the 20th century (and still available as the Viewmaster), stereos of landmark sites were often purchased by tourists; some companies such as Underwood and Underwood had photographers constantly making new images of areas around the world. Even department stores sold cheap stereo images: Eaton's not only sold stereos of other companies but had images of its own commercial activities and buildings. At least one company (Argus) still produces a stereo camera for amateur photographers.
Tintypes: Tintypes are unique images (like daguerreotypes), made on thin sheets of steel. They were made by coating the steel with wet collodion, sensitizing it with silver nitrate and exposing and developing it before the collodion dried. The development process provided a positive rather than negative image. Very cheap to make, tintypes usually appear brownish or reddish-brown in colour and do not have the same tonal range as paper photographs. Some photographers still take tintypes, and such images can occasionally be found at museums or in historical reconstructions.
Wet plate negative (or wet collodion negative): The earliest negatives were on paper, but these produced prints lacking the definition and clarity of daguerreotypes. A transparent material such as glass is excellent for making negatives, but difficult to stick a light-sensitive solution to. Scott Archer solved the problem in 1852 by using collodion. A solution of pyroxyline (gun cotton, which is made by dissolving cotton in nitrate acid) in alcohol and ether was mixed with silver nitrate. The viscous fluid was then poured onto a transparent glass plate, put in the camera, exposed and developed before the collodion dried. All these processes had to be carried out in the dark and at the time and place that the image was made, for once the collodion dried, the silver was sealed in and could not be developed. This made the process cumbersome in the field, but very well suited to portrait and studio work. Although many different attempts to improve the system were made, the wet collodion system was generally used until the 1880s when it was replaced by silver gelatin negatives. (See also ambrotype and tintype.)