Charles Harper Bennett (born 1840 in London, died 1927 in Sydney) was an English photographic pioneer.
He improved the gelatin silver process developed by Richard Leach Maddox, first in 1873 by a method of hardening the emulsion, making it more resistant to friction, and later in 1878 Bennett discovered that by prolonged heating the sensitivity of the emulsion could be greatly increased. [1] This increased sensitivity resulting enabled shooting at 1/25 second, paving the way for the snapshot.
An emulsion is a mixture of two or more liquids that are normally immiscible owing to liquid-liquid phase separation. Emulsions are part of a more general class of two-phase systems of matter called colloids. Although the terms colloid and emulsion are sometimes used interchangeably, emulsion should be used when both phases, dispersed and continuous, are liquids. In an emulsion, one liquid is dispersed in the other. Examples of emulsions include vinaigrettes, homogenized milk, liquid biomolecular condensates, and some cutting fluids for metal working.
Film stock is an analog medium that is used for recording motion pictures or animation. It is recorded on by a movie camera, developed, edited, and projected onto a screen using a movie projector. It 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. The emulsion will gradually darken if left exposed to light, but the process is too slow and incomplete to be of any practical use. Instead, a very short exposure to the image formed by a camera lens is used to produce only a very slight chemical change, proportional to the amount of light absorbed by each crystal. This creates an invisible latent image in the emulsion, which can be chemically developed into a visible photograph. In addition to visible light, all films are sensitive to X-rays and high-energy particles. Most are at least slightly sensitive to invisible ultraviolet (UV) light. Some special-purpose films are sensitive into the infrared (IR) region of the spectrum.
In photography, exposure is the amount of light per unit area reaching a frame of photographic film or the surface of an electronic image sensor, 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.
Film 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. A closely related ISO system is used to describe the relationship between exposure and output image lightness in digital cameras.
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.
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.
A silver halide is one of the chemical compounds that can form between the element silver (Ag) and one of the halogens. In particular, bromine (Br), chlorine (Cl), iodine (I) and fluorine (F) may each combine with silver to produce silver bromide (AgBr), silver chloride (AgCl), silver iodide (AgI), and three forms of silver fluoride, respectively.
Panchromatic emulsion is a type of black-and-white photographic emulsion that is sensitive to all wavelengths of visible light.
A latent image is an invisible image produced by the exposure to light of a photosensitive material such as photographic film. When photographic film is developed, the area that was exposed darkens and forms a visible image. In the early days of photography, the nature of the invisible change in the silver halide crystals of the film's emulsion coating was unknown, so the image was said to be "latent" until the film was treated with photographic developer.
A film badge dosimeter or film badge is a personal dosimeter used for monitoring cumulative radiation dose due to ionizing radiation.
In chemistry, orthochromasia is the property of a dye or stain to not change color on binding to a target, as opposed to metachromatic stains, which change color. The word is derived from the Greek orthos, and chromatic (color). Toluidine blue is an example of a partially orthochromatic dye, as it stains nucleic acids by its orthochromatic color (blue), but stains mast cell granules in its metachromatic color (red).
Tabular-grain film is a type of photographic film that includes nearly all color films, and many black and white films like T-MAX films from Kodak, Delta films from Ilford Photo and the Fujifilm Neopan films. The silver halide crystals in the film emulsion are flatter and more tabular.
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.
The merits of digital versus film photography were considered by photographers and filmmakers in the early 21st century after consumer digital cameras became widely available. Digital photography and digital cinematography have both advantages and disadvantages relative to still film and motion picture film photography. In the 21st century, photography came to be predominantly digital, but traditional photochemical methods continue to serve many users and applications.
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. The substrate is often flexible and known as a film base.
The Bennett scale, also called the Developmental Model of Intercultural Sensitivity (DMIS), was developed by Milton Bennett. The framework describes the different ways in which people can react to cultural differences. Bennett's initial idea was for trainers to utilize the model to evaluate trainees' intercultural awareness and help them improve intercultural sensitivity, also sometimes referred to as cultural sensitivity, which is the ability of accepting and adapting to a brand new and different culture.
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.
Cultural sensitivity, also referred to as cross-cultural sensitivity or cultural awareness, is the knowledge, awareness, and acceptance of other cultures and others' cultural identities. It is related to cultural competence, and is sometimes regarded as the precursor to the achievement of cultural competence, but is a more commonly used term. On the individual level, cultural sensitivity is a state of mind regarding interactions with those different from oneself. Cultural sensitivity enables travelers, workers, and others to successfully navigate interactions with a culture other than their own.
Kodak High-Speed Infrared film, also known as Kodak HIE, was a popular black-and-white infrared photographic film from Kodak. The film was sensitive to the visible light spectrum, infrared radiation up to 900nm in wavelength, and some ultraviolet radiation as well.
| General | |
|---|---|
| National libraries | |
| Art research institutes | |
| Other | |
