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Hurter–Driffield Curve
Sensitometry is the scientific study of light-sensitive materials, especially photographic film. The study has its origins in the work by Ferdinand Hurter and Vero Charles Driffield (circa 1876) with early black-and-white emulsions. They determined how the density of silver produced varied with the amount of light received, and the method and time of development. Details Plots of film density (log of opacity) versus the log of exposure are called characteristic curves, Hurter–Driffield curves, H–D curves, HD curves, H & D curves, D–logE curves, or D–logH curves. At moderate exposures, the overall shape is typically a bit like an "S" slanted so that its base and top are horizontal. There is usually a central region of the HD curve which approximates to a straight line, called the "linear" or "straight-line" portion; the slope of this region is called the gamma. The low end is called the "toe", and at the top, the curve rounds over to form the "shoulder". At extremely high ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
H&D Curve
H&D (), is a South Korean duo formed by Pocketdol Studio in 2020. The duo debuted on April 21, 2020, with ''Soulmate''. Members *Lee Han-gyul (이한결) *Nam Do-hyon (남도현) History Pre-debut Prior to their debut as a duo, both members had participated as contestants on multiple shows. Hangyul had previously debuted as a member of Yama and Hotchicks Entertainment's ballad group IM and in 2017 and 2018, competed in the show ''The Unit'' alongside his members. The group is considered to be disbanded as they've been inactive since. Dohyon previously competed in the show ''Under Nineteen'' in 2018 and 2019. Later in 2019, both Hangyul and Dohyon competed in ''Produce X 101'', representing MBK Entertainment, alongside fellow MBK trainee Kim Yeongsang. In the show's finale, Hangyul and Dohyon placed 7th and 8th respectively, making them part of the show's debut line-up and members of the group X1. They promoted with the group until their disbandment on January 6, 2020. After ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Film Speed
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. Relatively insensitive film, with a correspondingly lower speed index, requires more exposure to light to produce the same image density as a more sensitive film, and is thus commonly termed a ''slow film''. Highly sensitive films are correspondingly termed ''fast films''. In both digital and film photography, the reduction of exposure corresponding to use of higher sensitivities generally leads to reduced image quality (via coarser film grain or higher image noise of other types). In short, the higher the sensitivity, the grainier the image will be. Ultimately sensitivity is limited by the quantum efficiency of the film or sensor. Film speed measurement systems His ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zone System
The Zone System is a photographic technique for determining optimal film exposure and development, formulated by Ansel Adams and Fred Archer. Adams described the Zone System as " ..not an invention of mine; it is a codification of the principles of sensitometry, worked out by Fred Archer and myself at the Art Center School in Los Angeles, around 1939–40." The technique is based on the late 19th century sensitometry studies of Hurter and Driffield. The Zone System provides photographers with a systematic method of precisely defining the relationship between the way they visualize the photographic subject and the final results. Although it originated with black-and-white sheet film, the Zone System is also applicable to roll film, both black-and-white and color, negative and reversal, and to digital photography. Principles Visualization An expressive image involves the arrangement and rendering of various scene elements according to the photographer's desire. Achieving the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spectral Sensitivity
Spectral sensitivity is the relative efficiency of detection, of light or other signal, as a function of the frequency or wavelength of the signal. In visual neuroscience, spectral sensitivity is used to describe the different characteristics of the photopigments in the rod cells and cone cells in the retina of the eye. It is known that the rod cells are more suited to scotopic vision and cone cells to photopic vision, and that they differ in their sensitivity to different wavelengths of light. It has been established that the maximum spectral sensitivity of the human eye under daylight conditions is at a wavelength of 555 nm, while at night the peak shifts to 507 nm. In photography, film and sensors are often described in terms of their spectral sensitivity, to supplement their characteristic curves that describe their responsivity. A database of camera spectral sensitivity is created and its space analyzed. For X-ray films, the spectral sensitivity is chosen to b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Emanuel Goldberg
Emanuel Goldberg ( he, עמנואל גולדברג; yi, עמנואל גאָלדבערג; russian: Эмануэль Гольдберг) (born: 31 August 1881; died: 13 September 1970) was an Israeli physicist and inventor. He was born in Moscow and moved first to Germany and later to Israel. He described himself as "a chemist by learning, physicist by calling, and a mechanic by birth." He contributed a wide range of theoretic and practical advances relating to light and media and was the founding head of Zeiss Ikon, the famous photographic products company in Dresden, Germany. His inventions include microdots, the Kinamo movie camera, the Contax 35 mm camera, a very early search engine, and equipment for sensitometry. Biography Goldberg was born in Moscow on 31 August 1881 (19 August 1881 in the Old Style, Julian calendar, sometimes given in error as 1 September) the son of Grigorii Ignat'evich Goldberg, a distinguished Colonel (Polkovnik) in the Tsar's military medical ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Julius Scheiner
Julius Scheiner (25 November 1858 – 20 December 1913) was a German astronomer, born in Cologne and educated at Bonn. He became assistant at the astrophysical observatory in Potsdam in 1887 and its observer in chief in 1898, three years after his appointment to the chair of astrophysics in the University of Berlin. Scheiner paid special attention to celestial photography and wrote ''Die Spektralanalyse der Gestirne'' (1890); ''Lehrbuch der Photographie der Gestirne'' (1897); ''Strahlung und Temperatur der Sonne'' (1899); ''Der Bau des Weltalls'' (1901); third edition (1909). In 1899 he began the publication of the ''Photographische Himmelskarte; Zone +31° bis +40° Deklination''. He is also credited with developing the first system for measuring the sensitivity of photographic emulsions in 1894,Martin Riat. ''Graphische Techniken - Eine Einführung in die verschiedenen Techniken und ihre Geschichte''. E-Book, 3. German edition, Burriana, spring 2006, based on a Catalan book: ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Josef Maria Eder
Josef Maria Eder (16 March 1855 – 18 October 1944) was an Austrian chemist who specialized in the chemistry of photography, and who wrote a comprehensive early history of the technical development of chemical photography. Life and work Eder was born in Krems an der Donau in 1855. He studied chemistry, physics and mathematics at the Vienna University of Technology and at the University of Vienna. In 1876, he received his PhD and in 1879, after his habilitation, became lecturer at the Vienna University of Technology. His research then was focused on the chemistry of photography. After spending some time at the Staatliche Gewerbeschule Vienna, he became lecturer at the Höhere Gewerbeschule Vienna. This change improved his possibilities for doing research. In the following years, Eder developed sensitized gelatin silver process. Orthochromatic photographic plates, in combination with a color filter counter-acting the plates' inhomogeneous sensitivity to light of different wavelength ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hurter And Driffield
Ferdinand Hurter (1844–1898) and Vero Charles Driffield (1848–1915) were nineteenth-century photographic scientists who brought quantitative scientific practice to photography through the methods of sensitometry and densitometry. Among their other innovations was a photographic exposure estimation device known as an actinograph. See also * H&D speed numbers, originally described in 1890, for film speed 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 relations ... measurements References External links A brief history of Hurter and Driffield by Ron Callender in ''Encyclopedia of Nineteenth-century Photography'' 2008 pp.732-4 History of photography {{photo-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leon Warnerke
Leon Warnerke (26 May 1837 – 7 October 1900) was a Polish civil engineer and inventor in the field of photography, independence activist, revolutionary and successful forger. Leon Warnerke was a pseudonym; his real name was Władysław Małachowski. Early career Władysław Małachowski's dates and places of birth and death are unconfirmed. He graduated from the Institute of Communication Engineers in St. Petersburg in 1859, then worked in Vilnius on the construction of the Petersburg-Warsaw Railway. In 1863 he joined the January Uprising and then became a member of the National Government in Vilnius. After the collapse of the uprising, the police, on the orders of general M. Murawjow, issued an arrest warrant for Małachowski with a reward of 10 thousand zlotys, as a result of which he was forced to flee the country. He escaped with his wife on board an English ship to Great Britain, carrying a false passport in the name of Warnerke. Around 1870, he settled with his wife ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Densitometry
Densitometry is the quantitative measurement of optical density in light-sensitive materials, such as photographic paper or photographic film, due to exposure to light. Overview Optical density is a result of the darkness of a developed picture and can be expressed absolutely as the number of dark spots (i.e., silver grains in developed films) in a given area, but usually it is a relative value, expressed in a scale. Since density is usually measured by the decrease in the amount of light which shines through a transparent film, it is also called ''absorptiometry'', the measure of light absorption through the medium. The corresponding measuring device is called a densitometer (''absorptiometer''). The decadic (base-10) logarithm of the reciprocal of the transmittance is called the absorbance or ''density''. ''DMax'' and ''DMin'' refer to the maximum and minimum density that can be produced by the material. The difference between the two is the ''density range''. The density ra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Film Gamma Values
A film also called a movie, motion picture, moving picture, picture, photoplay or (slang) flick is a work of visual art that simulates experiences and otherwise communicates ideas, stories, perceptions, feelings, beauty, or atmosphere through the use of moving images. These images are generally accompanied by sound and, more rarely, other sensory stimulations. The word "cinema", short for cinematography, is often used to refer to filmmaking and the film industry, and to the art form that is the result of it. Recording and transmission of film The moving images of a film are created by photographing actual scenes with a motion-picture camera, by photographing drawings or miniature models using traditional animation techniques, by means of CGI and computer animation, or by a combination of some or all of these techniques, and other visual effects. Before the introduction of digital production, series of still images were recorded on a strip of chemically sensitiz ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
