CelluloidCelluloids are a class of materials produced by mixing nitrocellulose and camphor, often with added dyes and other agents. Once much more common for its use as photographic film before the advent of safer methods, celluloid's common contemporary uses are for manufacturing table tennis balls, musical instruments, combs, office equipment, fountain pen bodies, and guitar picks. Nitrocellulose-based plastics slightly predate celluloid. Collodion, invented in 1848 and used as a wound dressing and an emulsion for photographic plates, is dried to a celluloid like film.
DaguerreotypeDaguerreotype (dəˈɡɛər(i.)əˌtaɪp,_-(i.)oʊ-; daguerréotype) was the first publicly available photographic process; it was widely used during the 1840s and 1850s. "Daguerreotype" also refers to an image created through this process. Invented by Louis Daguerre and introduced worldwide in 1839, the daguerreotype was almost completely superseded by 1860 with new, less expensive processes, such as ambrotype (collodion process), that yield more readily viewable images.
Reciprocity (photography)In photography, reciprocity is the inverse relationship between the intensity and duration of light that determines the reaction of light-sensitive material. Within a normal exposure range for film stock, for example, the reciprocity law states that the film response will be determined by the total exposure, defined as intensity × time. Therefore, the same response (for example, the optical density of the developed film) can result from reducing duration and increasing light intensity, and vice versa.
Infrared photographyTop: tree photographed in the near infrared range. Bottom: same tree in the visible part of the spectrum. In infrared photography, the film or used is sensitive to infrared light. The part of the spectrum used is referred to as near-infrared to distinguish it from far-infrared, which is the domain of thermal imaging. Wavelengths used for photography range from about 700 nm to about 900 nm.
Color balanceIn photography and , color balance is the global adjustment of the intensities of the colors (typically red, green, and blue primary colors). An important goal of this adjustment is to render specific colors – particularly neutral colors like white or grey – correctly. Hence, the general method is sometimes called gray balance, neutral balance, or white balance. Color balance changes the overall mixture of colors in an image and is used for color correction.
Exposure (photography)In photography, exposure is the amount of light per unit area (the 's illuminance times the exposure time) reaching a frame of photographic film or the surface of an electronic , as determined by shutter speed, lens F-number, and scene luminance. Exposure is measured in lux seconds, and can be computed from exposure value (EV) and scene luminance in a specified region. An "exposure" is a single shutter cycle.
Agfa-GevaertAgfa-Gevaert N.V. (Agfa) is a Belgian-German multinational corporation that develops, manufactures, and distributes analogue and digital imaging products, software, and systems. The company began as a dye manufacturer in 1867. In 1925, the company merged with several other German chemical companies to become a chemicals giant IG Farben. IG Farben would go on to play major role in the economy of Nazi Germany. It extensively employed forced and slave labor during the Nazi period, and produced the notorious Zyklon B chemical used in The Holocaust.
Film speedFilm speed is the measure of a photographic film's sensitivity to light, determined by sensitometry and measured on various numerical scales, the most recent being the ISO system introduced in the mid-1970s. A closely related ISO system is used to describe the relationship between exposure and output image lightness in digital cameras. Prior to ISO gaining traction the best known systems were ASA in the U.S. and DIN in Europe. The term speed comes from the early days of photography.
Polaroid CorporationPolaroid was an American company best known for its instant film and cameras, which now survives as a brand for consumer electronics. The company was founded in 1937 by Edwin H. Land, to exploit the use of his Polaroid polarizing polymer. Land and Polaroid created the first instant camera, the Land Camera, in 1948. Land ran the company until 1981. Its peak employment was 21,000 in 1978, and its peak revenue was $3 billion in 1991. Polaroid Corporation was declared bankrupt in 2001; its brand and assets were sold off.
Photographic processingPhotographic 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 . Photographic processing transforms the into a visible image, makes this permanent and renders it insensitive to light. All processes based upon the gelatin silver process are similar, regardless of the film or paper's manufacturer. Exceptional variations include instant films such as those made by Polaroid and thermally developed films.
