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Collodion
Collodion is a flammable, syrupy solution of nitrocellulose in Diethyl ether, ether and Alcohol (chemistry), 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 Collodion was also the basis of most Collodion process, wet-plate photography until it was superseded by modern gelatin emulsions.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 diethyl ether, ether. They devised a mixture of ether 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 "collodi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Collodion Process
The collodion process is an early photography, photographic process for the production of grayscale images. The collodion process – mostly synonymized with the term "''wet-plate process''", requires the photographic material to be coated, sensitized, exposed, and developed within the span of about fifteen minutes, necessitating a portable darkroom for use in the field. Collodion is normally used in its wet form, but it can also be used in its dry form, at the cost of greatly increased exposure time. The increased exposure time made the dry form unsuitable for the usual portraiture work of most professional photographers of the 19th century. The use of the dry form was mostly confined to landscape photography and other special applications where exposure times sometimes longer than a half hour were tolerable. History Gustave Le Gray first theorized about the collodion process, publishing a method in 1850 that was "theoretical at best", but Frederick Scott Archer was credited wi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ambrotype
The ambrotype, 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. As a cheaper alternative to the French daguerreotype, ambrotypes came to replace them. Like a print on paper, it is viewed by reflected light. Like the daguerreotype or 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. The term ''ambrotype'' comes from ''ambrotos'', "immortal", and ''typos'', "impression". 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 d ... [...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. In the 20th century, it was adapted to automobile lacquer and adhesives. 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 organic chemistry, nitrocellulose is a nitrate ester, not 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 photographic film, 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 Mr. Massey of 116 Leadenhall Street. On the recommendation of Edward Hawkins he trained at the Royal Academy Schools as 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tintype
A tintype, also known as a melanotype or ferrotype, is a photograph made by creating a direct positive on a thin sheet of metal, colloquially called 'tin' (though not actually tinplate, tin-coated), coated with a dark lacquer or Enamel paint, enamel and used as the support for the photographic emulsion. It was introduced in 1853 by Adolphe Alexandre Martin in Paris. It competed with both the ambrotype process and the older and established daguerreotype, finding particular adoption in North America. Tintypes enjoyed their widest use during the 1860s and 1870s, but lesser use of the medium persisted into 1930s and it has been revived as a novelty and fine art form in the 21st century. It has been described as the first "truly democratic" medium for mass portraiture. Tintypes were particularly used for portraits. They were at first usually made in a formal photographic studio, like daguerreotypes and other early types of photographs. At the time though the process like the profe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ferrotype
A tintype, also known as a melanotype or ferrotype, is a photograph made by creating a direct positive on a thin sheet of metal, colloquially called 'tin' (though not actually tin-coated), coated with a dark lacquer or enamel and used as the support for the photographic emulsion. It was introduced in 1853 by Adolphe Alexandre Martin in Paris. It competed with both the ambrotype process and the older and established daguerreotype, finding particular adoption in North America. Tintypes enjoyed their widest use during the 1860s and 1870s, but lesser use of the medium persisted into 1930s and it has been revived as a novelty and fine art form in the 21st century. It has been described as the first "truly democratic" medium for mass portraiture. Tintypes were particularly used for portraits. They were at first usually made in a formal photographic studio, like daguerreotypes and other early types of photographs. At the time though the process like the professional were calle ... [...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 (x = 5), which is a white solid that dissolves well in water. The compound is a reducing agent and a ligand, and these properties underpin its applications. Uses Sodium thiosulfate is used predominantly in dyeing. It converts some dyes to their soluble colorless "leuco" forms. 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. It is on the World Health Organization's List of Essential Medicines. Other uses include topical treatment of ringworm and tinea versicolor, and treating some side effects of hemodialysis and chemotherapy. In September 2022, the U.S. Food and Drug Administration (FDA) approved sodium thiosulfate under the trade name Pedmark to lessen the risk of oto ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Potassium Cyanide
Potassium cyanide is a compound with the formula KCN. It is a colorless salt, similar in appearance to sugar, that is highly soluble in water. Most KCN is used in gold mining, organic synthesis, and electroplating. Smaller applications include jewellery for chemical gilding and buffing. Potassium cyanide is highly toxic, and a dose of 200 to 300 milligrams will kill nearly any human. The moist solid emits small amounts of hydrogen cyanide due to hydrolysis (reaction with water). Hydrogen cyanide is often described as having an odor resembling that of bitter almonds. The taste of potassium cyanide has been described as acrid and bitter, with a burning sensation similar to lye. Potassium cyanide kills so rapidly its taste hasn't been reliably documented, in 2006 an Indian man named M.P. Prasad committed suicide using potassium cyanide. He was a goldsmith and was aware of the mystery behind its taste. In the suicide note Prasad left, the final words written were that potassium ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ferrous Sulfate
Iron(II) sulfate or ferrous sulfate (British English: sulphate instead of sulfate) denotes a range of salts with the formula Fe SO4·''x''H2O. These compounds exist most commonly as the heptahydrate (''x'' = 7), but several values for x are known. The hydrated form is used medically to treat or prevent iron deficiency, and also for industrial applications. Known since ancient times as copperas and as green vitriol (vitriol is an archaic name for hydrated sulfate minerals), the blue-green heptahydrate (hydrate with 7 molecules of water) is the most common form of this material. All the iron(II) sulfates dissolve in water to give the same aquo complex e(H2O)6sup>2+, which has octahedral molecular geometry and is paramagnetic. The name copperas dates from times when the copper(II) sulfate was known as blue copperas, and perhaps in analogy, iron(II) and zinc sulfate were known respectively as green and white copperas. It is on the World Health Organization's List of Ess ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Darkroom
A darkroom is used to process photographic film, make Photographic printing, prints and carry out other associated tasks. It is a room that can be made completely dark to allow the processing of 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 List of photographic processes, processing color film (''see C-41 process'') and printing color photographs and also to the rise, first of Instant camera, instant photography te ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iodide
An iodide ion is 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. The l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
