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Dry plate, also known as gelatin process, is an improved type of photographic plate. It was invented by Dr. Richard L. Maddox in 1871, and had become so widely adopted by 1879 that the first dry plate factory had been established. With much of the complex chemistry work centralized into a factory, the new process simplified the work of photographers, allowing them to expand their business.
Gelatin emulsions, as proposed by Maddox, were very sensitive to touch and mechanical friction and were not much more sensitive to light than collodion emulsions. Charles Harper Bennett discovered a method of hardening the emulsion, making it more resistant to friction in 1873. In 1878, Bennett discovered that by prolonged heating, the sensitivity of the emulsion could be greatly increased. George Eastman developed a machine to coat glass plates in 1879 and opened the Eastman Film and Dry Plate Company,reducing the cost of photography. A competitor of Eastman in the development and manufacture of gelatin dry plates was the architectural photographer Albert Levy.
The following list comprises significant milestones in the development of photography technology.
The collodion process is an early photographic process. The collodion process, mostly synonymous with the "collodion wet plate process", requires the photographic material to be coated, sensitized, exposed and developed within the span of about fifteen minutes, necessitating a portable darkroom for use in the field. Collodion is normally used in its wet form, but can also be used in humid ("preserved") or dry form, at the cost of greatly increased exposure time. The latter made the dry form unsuitable for the usual portraiture work of most professional photographers of the 19th century. The use of the dry form was therefore mostly confined to landscape photography and other special applications where minutes-long exposure times were tolerable.
Photographic paper is a paper coated with a light-sensitive chemical formula, used for making photographic prints. When photographic paper is exposed to light, it captures a latent image that is then developed to form a visible image; with most papers the image density from exposure can be sufficient to not require further development, aside from fixing and clearing, though latent exposure is also usually present. The light-sensitive layer of the paper is called the emulsion. The most common chemistry was based on silver salts but other alternatives have also been used.
Photographic plates preceded photographic film as a capture medium in photography, and were still used in some communities up until the late 20th century. The light-sensitive emulsion of silver salts was coated on a glass plate, typically thinner than common window glass, instead of a clear plastic film.
Collodion is a flammable, syrupy solution of pyroxylin in ether and alcohol. There are two basic types: flexible and non-flexible. The flexible type is often used as a surgical dressing or to hold dressings in place. When painted on the skin, collodion dries to form a flexible nitrocellulose film. While it is initially colorless, it discolors over time. Non-flexible collodion is often used in theatrical make-up.
Color photography is photography that uses media capable of reproducing colors. By contrast, black-and-white (monochrome) photography records only a single channel of luminance (brightness) and uses media capable only of showing shades of gray.
The gelatin silver process is the photographic process used with currently available black-and-white films and printing papers. A suspension of silver salts in gelatin is coated onto a support such as glass, flexible plastic or film, baryta paper, or resin-coated paper. These light-sensitive materials are stable under normal keeping conditions and are able to be exposed and processed even many years after their manufacture. This is in contrast to the collodion wet-plate process dominant from the 1850s–1880s, which had to be exposed and developed immediately after coating.
The term alternative process refers to any non-traditional or non-commercial photographic printing process. Currently the standard analog photographic printing process is the gelatin silver process, and standard digital processes include the pigment print, and digital laser exposures on traditional color photographic paper.
Hermann Wilhelm Vogel was a German photochemist and photographer who discovered dye sensitization, which is of great importance to photography.
The history of photography began in remote antiquity with the discovery of two critical principles: camera obscura image projection and the observation that some substances are visibly altered by exposure to light. There are no artifacts or descriptions that indicate any attempt to capture images with light sensitive materials prior to the 18th century.
The conservation and restoration of photographs is the study of the physical care and treatment of photographic materials. It covers both efforts undertaken by photograph conservators, librarians, archivists, and museum curators who manage photograph collections at a variety of cultural heritage institutions, as well as steps taken to preserve collections of personal and family photographs. It is an umbrella term that includes both preventative preservation activities such as environmental control and conservation techniques that involve treating individual items. Both preservation and conservation require an in-depth understanding of how photographs are made, and the causes and prevention of deterioration. Conservator-restorers use this knowledge to treat photographic materials, stabilizing them from further deterioration, and sometimes restoring them for aesthetic purposes.
Richard Leach Maddox was an English photographer and physician who invented lightweight gelatin negative plates for photography in 1871.
A chromogenic print, also known as a silver halide print, or a dye coupler print, is a photographic print made from a color negative, transparency, or digital image, and developed using a chromogenic process. They are composed of three layers of gelatin, each containing an emulsion of silver halide, which is used as a light-sensitive material, and a different dye coupler of subtractive color which together, when developed, form a full-color image.
Frederick Charles Luther Wratten was an English inventor.
Photographic emulsion is a light-sensitive colloid used in film-based photography. Most commonly, in silver-gelatin photography, it consists of silver halide crystals dispersed in gelatin. The emulsion is usually coated onto a substrate of glass, films, paper, or fabric.
Photographic film is a strip or sheet of transparent plastic film base coated on one side with a gelatin emulsion containing microscopically small light-sensitive silver halide crystals. The sizes and other characteristics of the crystals determine the sensitivity, contrast, and resolution of the film.
Maddox Peak is a peak standing at the south side of the mouth of Carbutt Glacier, east of Flandres Bay, on the west coast of Graham Land, Antarctica. The peak appears on an Argentine government chart of 1954. It was named by the UK Antarctic Place-Names Committee in 1960 for English physician and pioneer of photography Richard L. Maddox, who invented the gelatin emulsion process of dry-plate photography in 1871, revolutionizing photographic technique.
Photographic hypersensitization refers to a set of processes that can be applied to photographic film or plates before exposing. One or more of these processes is often needed to make photographic materials work better in long exposures.
Charles Harper Bennett was an English photographic pioneer.
The conservation and restoration of photographic plates is the process of caring for and maintaining photographic plates in order to preserve their materials and content. It covers the necessary measures that can be taken by conservators, curators, collections managers, and other museum professionals to conserve the material unique to photographic plate processes. This practice includes understanding the composition and agents of deterioration of photographic plates, as well as the preventive conservation and interventive conservation measures that can be taken to increase their longevity.