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Collodion
Collodion is a flammable, syrupy solution of nitrocellulose 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. Collodion was also the basis of most wet-plate photography until it was superseded by modern gelatin emulsions. History In 1846 Louis-Nicolas Ménard and Florès Domonte discovered that cellulose nitrate could be dissolved in ether. They devised a mixture of ether (ethoxyethane) as the solvent and ethanol as a diluent that rendered cellulose nitrate into a clear gelatinous liquid. Collodion was first used medically as a dressing in 1847 by the Boston physician John Parker Maynard. The solution was dubbed "collodion" (from the Greek κολλώδης (''kollodis'') ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nitrocellulose
Nitrocellulose (also known as cellulose nitrate, flash paper, flash cotton, guncotton, pyroxylin and flash string, depending on form) is a highly flammable compound formed by nitrating cellulose through exposure to a mixture of nitric acid and sulfuric acid. One of its first major uses was as guncotton, a replacement for gunpowder as propellant in firearms. It was also used to replace gunpowder as a low-order explosive in mining and other applications. In the form of collodion it was also a critical component in an early photographic emulsion, the use of which revolutionized photography in the 1860s. Production The process uses a mixture of nitric acid and sulfuric acid to convert cellulose into nitrocellulose. The quality of the cellulose is important. Hemicellulose, lignin, pentosans, and mineral salts give inferior nitrocelluloses. In precise chemical terms, nitrocellulose is not a nitro compound, but a nitrate ester. The glucose repeat unit (anhydroglucose) within th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cellulose Nitrate
Nitrocellulose (also known as cellulose nitrate, flash paper, flash cotton, guncotton, pyroxylin and flash string, depending on form) is a highly flammable compound formed by nitrating cellulose through exposure to a mixture of nitric acid and sulfuric acid. One of its first major uses was as guncotton, a replacement for gunpowder as propellant in firearms. It was also used to replace gunpowder as a low-order explosive in mining and other applications. In the form of collodion it was also a critical component in an early photographic emulsion, the use of which revolutionized photography in the 1860s. Production The process uses a mixture of nitric acid and sulfuric acid to convert cellulose into nitrocellulose. The quality of the cellulose is important. Hemicellulose, lignin, pentosans, and mineral salts give inferior nitrocelluloses. In precise chemical terms, nitrocellulose is not a nitro compound, but a nitrate ester. The glucose repeat unit (anhydroglucose) within the ce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ambrotype
The ambrotype (from grc, ἀμβροτός — “immortal”, and — “impression”) also known as a collodion positive in the UK, is a positive photograph on glass made by a variant of the wet plate collodion process. Like a print on paper, it is viewed by reflected light. Like the daguerreotype, which it replaced, and like the prints produced by a Polaroid camera, each is a unique original that could only be duplicated by using a camera to copy it. The ambrotype was introduced in the 1850s. During the 1860s it was superseded by the tintype, a similar photograph on thin black-lacquered iron, hard to distinguish from an ambrotype if under glass. Process One side of a clean glass plate was coated with a thin layer of iodized collodion, then dipped in a silver nitrate solution. The plate was exposed in the camera while still wet. Exposure times varied from five to sixty seconds or more depending on the brightness of the lighting and the speed of the came ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Darkroom
A darkroom is used to process photographic film, to make prints and to carry out other associated tasks. It is a room that can be made completely dark to allow the processing of the light-sensitive photographic materials, including film and photographic paper. Various equipment is used in the darkroom, including an enlarger, baths containing chemicals, and running water. Darkrooms have been used since the inception of photography in the early 19th century. Darkrooms have many various manifestations, from the elaborate space used by Ansel Adams to a retooled ambulance wagon used by Timothy H. O'Sullivan. From the initial development of the film to the creation of prints, the darkroom process allows complete control over the medium. Due to the popularity of color photography and complexity of processing color film (''see C-41 process'') and printing color photographs and also to the rise, first of instant photography technology and later digital photography, darkrooms are de ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sodium Thiosulfate
Sodium thiosulfate (sodium thiosulphate) is an inorganic compound with the formula . Typically it is available as the white or colorless pentahydrate, . The solid is an efflorescent (loses water readily) crystalline substance that dissolves well in water. Sodium thiosulfate is used in gold mining, water treatment, analytical chemistry, the development of silver-based photographic film and prints, and medicine. The medical uses of sodium thiosulfate include treatment of cyanide poisoning and pityriasis. It is on the World Health Organization's List of Essential Medicines. Uses Sodium thiosulfate is used predominantly in industry. For example, it is used to convert dyes to their soluble colorless forms, which are called leuco. It is also used to bleach "wool, cotton, silk, ...soaps, glues, clay, sand, bauxite, and... edible oils, edible fats, and gelatin." Medical uses Sodium thiosulfate is used in the treatment of cyanide poisoning. Other uses include topical treatment ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ferrotype
A tintype, also known as a melainotype or ferrotype, is a photograph made by creating a direct positive on a thin sheet of metal coated with a dark lacquer or enamel and used as the support for the photographic emulsion. Tintypes enjoyed their widest use during the 1860s and 1870s, but lesser use of the medium persisted into the early 20th century and it has been revived as a novelty and fine art form in the 21st. Tintype portraits were at first usually made in a formal photographic studio, like daguerreotypes and other early types of photographs, but later they were most commonly made by photographers working in booths or the open air at fairs and carnivals, as well as by itinerant sidewalk photographers. Because the lacquered iron support (there is no actual tin used) was resilient and did not need drying, a tintype could be developed and fixed and handed to the customer only a few minutes after the picture had been taken. The tintype photograph saw more uses and captured a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frederick Scott Archer
] Frederick Scott Archer (1813 – 1 May 1857) was an English photographer and sculptor who is best known for having invented the photographic collodion process which preceded the modern gelatin emulsion. He was born in either Bishop's Stortford or Hertford, within the county of Hertfordshire, England (United Kingdom of Great Britain and Ireland) and is remembered mainly for this single achievement which greatly increased the accessibility of photography for the general public. Life Scott Archer was the second son of a butcher in Bishops Stortford in Hertfordshire who went to London to take an apprenticeship as a goldsmith and silversmith with a Mr Massey of 116 Leadenhall Street. On the recommendation of Edward Hawkins he trained at the Royal Academy Schools a sculptor and found calotype photography useful as a way of capturing images of his sculptures. Dissatisfied with the poor definition and contrast of the calotype and the long exposures needed, Scott Archer inven ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tintype
A tintype, also known as a melainotype or ferrotype, is a photograph made by creating a direct positive on a thin sheet of metal coated with a dark lacquer or enamel and used as the support for the photographic emulsion. Tintypes enjoyed their widest use during the 1860s and 1870s, but lesser use of the medium persisted into the early 20th century and it has been revived as a novelty and fine art form in the 21st. Tintype portraits were at first usually made in a formal photographic studio, like daguerreotypes and other early types of photographs, but later they were most commonly made by photographers working in booths or the open air at fairs and carnivals, as well as by itinerant sidewalk photographers. Because the lacquered iron support (there is no actual tin used) was resilient and did not need drying, a tintype could be developed and fixed and handed to the customer only a few minutes after the picture had been taken. The tintype photograph saw more uses and captured ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iodide
An iodide ion is the ion I−. Compounds with iodine in formal oxidation state −1 are called iodides. In everyday life, iodide is most commonly encountered as a component of iodized salt, which many governments mandate. Worldwide, iodine deficiency affects two billion people and is the leading preventable cause of intellectual disability. Structure and characteristics of inorganic iodides Iodide is one of the largest monatomic anions. It is assigned a radius of around 206 picometers. For comparison, the lighter halides are considerably smaller: bromide (196 pm), chloride (181 pm), and fluoride (133 pm). In part because of its size, iodide forms relatively weak bonds with most elements. Most iodide salts are soluble in water, but often less so than the related chlorides and bromides. Iodide, being large, is less hydrophilic compared to the smaller anions. One consequence of this is that sodium iodide is highly soluble in acetone, whereas sodium chloride is not ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bromide
A bromide ion is the negatively charged form (Br−) of the element bromine, a member of the halogens group on the periodic table. Most bromides are colorless. Bromides have many practical roles, being found in anticonvulsants, flame-retardant materials, and cell stains. Although uncommon, chronic toxicity from bromide can result in bromism, a syndrome with multiple neurological symptoms. Bromide toxicity can also cause a type of skin eruption, see potassium bromide. The bromide ion has an ionic radius of 196 pm. Natural occurrence Bromide is present in typical seawater (35 PSU) with a concentration of around 65 mg/L, which is about 0.2% of all dissolved salts. Seafood and deep sea plants generally have higher levels than land-derived foods. Bromargyrite—natural, crystalline silver bromide—is the most common bromide mineral known but is still very rare. In addition to silver, bromine is also in minerals combined with mercury and copper. Formation and rea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alfred Stieglitz By Frank S
Alfred may refer to: Arts and entertainment *'' Alfred J. Kwak'', Dutch-German-Japanese anime television series * ''Alfred'' (Arne opera), a 1740 masque by Thomas Arne * ''Alfred'' (Dvořák), an 1870 opera by Antonín Dvořák *"Alfred (Interlude)" and "Alfred (Outro)", songs by Eminem from the 2020 album '' Music to Be Murdered By'' Business and organisations * Alfred, a radio station in Shaftesbury, England *Alfred Music, an American music publisher *Alfred University, New York, U.S. *The Alfred Hospital, a hospital in Melbourne, Australia People * Alfred (name) includes a list of people and fictional characters called Alfred * Alfred the Great (848/49 – 899), or Alfred I, a king of the West Saxons and of the Anglo-Saxons Places Antarctica * Mount Alfred (Antarctica) Australia * Alfredtown, New South Wales * County of Alfred, South Australia Canada * Alfred and Plantagenet, Ontario * Alfred Island, Nunavut * Mount Alfred, British Columbia United States * Alfred, Maine ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Blue
Blue is one of the three primary colours in the RYB colour model (traditional colour theory), as well as in the RGB (additive) colour model. It lies between violet and cyan on the spectrum of visible light. The eye perceives blue when observing light with a dominant wavelength between approximately 450 and 495 nanometres. Most blues contain a slight mixture of other colours; azure contains some green, while ultramarine contains some violet. The clear daytime sky and the deep sea appear blue because of an optical effect known as Rayleigh scattering. An optical effect called Tyndall effect explains blue eyes. Distant objects appear more blue because of another optical effect called aerial perspective. Blue has been an important colour in art and decoration since ancient times. The semi-precious stone lapis lazuli was used in ancient Egypt for jewellery and ornament and later, in the Renaissance, to make the pigment ultramarine, the most expensive of all pigments. I ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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