Kodachrome is the brand name for a color reversal film introduced by Eastman Kodak in 1935. It was one of the first successful color materials and was used for both cinematography and still photography. For many years Kodachrome was widely used for professional color photography, especially for images intended for publication in print media. Because of its complex processing requirements, the film was sold process-paid in the United States until 1954, when a legal ruling prohibited that. However, the arrangement continued in other markets.
Photographic processing or photographic development is the chemical means by which photographic film or paper is treated after photographic exposure to produce a negative or positive image. Photographic processing transforms the latent image into a visible image, makes this permanent and renders it insensitive to light.
Photographic paper is a paper coated with a light-sensitive chemical formula, like photographic film, 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 halide but other alternatives have also been used.
The E-6 process is a chromogenic photographic process for developing Ektachrome, Fujichrome and other color reversal photographic film.
In the processing of photographic films, plates or papers, the photographic developer is one or more chemicals that convert the latent image to a visible image. Developing agents achieve this conversion by reducing the silver halides, which are pale-colored, into silver metal, which is black. The conversion occurs within the gelatine matrix. The special feature of photography is that the developer acts more quickly on those particles of silver halides that have been exposed to light. Paper left in developer will eventually reduce all the silver halides and turn black. Generally, the longer a developer is allowed to work, the darker the image.
Color photography is photography that uses media capable of capturing and reproducing colors. By contrast, black-and-white or gray-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 most commonly used chemical process in black-and-white photography, and is the fundamental chemical process for modern analog color photography. As such, films and printing papers available for analog photography rarely rely on any other chemical process to record an image. 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 was an improvement on the collodion wet-plate process dominant from the 1850s–1880s, which had to be exposed and developed immediately after coating.
C-41 is a chromogenic color print film developing process introduced by Kodak in 1972, superseding the C-22 process. C-41, also known as CN-16 by Fuji, CNK-4 by Konica, and AP-70 by AGFA, is the most popular film process in use, with most photofinishing labs devoting at least one machine to this development process.
Potassium dichromate, K2Cr2O7, is a common inorganic chemical reagent, most commonly used as an oxidizing agent in various laboratory and industrial applications. As with all hexavalent chromium compounds, it is acutely and chronically harmful to health. It is a crystalline ionic solid with a very bright, red-orange color. The salt is popular in the laboratory because it is not deliquescent, in contrast to the more industrially relevant salt sodium dichromate.
Ilfochrome is a dye destruction positive-to-positive photographic process used for the reproduction of film transparencies on photographic paper. The prints are made on a dimensionally stable polyester base as opposed to traditional paper base. Since it uses 13 layers of azo dyes sealed in a polyester base, the print will not fade, discolour, or deteriorate for an extended time. Accelerated aging tests conducted by Henry Wilhelm rated the process as producing prints which, framed under glass, would last for 29 years before color shifts could be detected. Characteristics of Ilfochrome prints are image clarity, color purity, and being an archival process able to produce critical accuracy to the original transparency.
Print permanence refers to the longevity of printed material, especially photographs, and preservation issues. Over time, the optical density, color balance, lustre, and other qualities of a print will degrade. The rate at which deterioration occurs depends primarily on two main factors: the print itself, that is, the colorants used to form the image and the medium on which image resides, and the type of environment the print is exposed to.
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.
Chromogenic photography is photography that works by a chromogen forming a conventional silver image and then replacing it with a dye image. Most films and papers used for color photography today are chromogenic, using three layers, each providing their own subtractive color. Some chromogenic films provide black-and-white negatives, and are processed in standard color developers. In this case, the dyes are a neutral color.
A chromogenic print, also known as a C-print or C-type print, 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.
Color motion picture film refers both to unexposed color photographic film in a format suitable for use in a motion picture camera, and to finished motion picture film, ready for use in a projector, which bears images in color.
K-14 was the most recent version of the developing process for Kodak's Kodachrome transparency film before its discontinuation. It superseded previous versions of the Kodachrome process used with older films.
The following outline is provided as an overview of and topical guide to photography:
In still photography, Kodak's Kodacolor brand has been associated with various color negative films since 1942. Kodak claims that Kodacolor was "the world's first true color negative film". More accurately, it was the first color negative film intended for making paper prints: in 1939, Agfa had introduced a 35 mm Agfacolor negative film for use by the German motion picture industry, in which the negative was used only for making positive projection prints on 35 mm film. There have been several varieties of Kodacolor negative film, including Kodacolor-X, Kodacolor VR and Kodacolor Gold.
Thermal paper is a special fine paper that is coated with a material formulated to change color when exposed to heat. It is used in thermal printers, particularly in inexpensive or lightweight devices such as adding machines, cash registers, and credit card terminals.
Photographic film is a strip or sheet of transparent 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.
