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Van Dyke Brown (printing)
Van Dyke brown is a printing process named after Anthony van Dyck. It involves coating a canvas with ferric ammonium citrate, tartaric acid, and silver nitrate, then exposing it to ultraviolet light. The canvas can be washed with water, and hypo to keep the solutions in place. The image created has a Van Dyke brown color when it's completed, and unlike other printing methods, does not require a 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 .... The Van Dyke brown process was patented in Germany in 1895 by Arndt and Troost. It was originally called many different names, such as sepia print or brown print. It has even been called kallitype, however that process uses ferric oxalate instead of ferric ammonium citrate. Concerns have been voiced about the archival qual ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anthony Van Dyck
Sir Anthony van Dyck (; ; 22 March 1599 – 9 December 1641) was a Flemish Baroque painting, Flemish Baroque artist who became the leading court painter in England after success in the Spanish Netherlands and Italy. The seventh child of Frans van Dyck, a wealthy silk merchant in Antwerp, Anthony painted from an early age. He was successful as an independent painter in his late teens and became a master in the Guild of Saint Luke, Antwerp Guild on 18 October 1617.Davies, Justin. 'A new date for Anthony van Dyck's free mastership'. ''The Burlington Magazine'' 165 (February 2023), pp. 162–165. By this time, he was working in the studio of the leading northern painter of the day, Peter Paul Rubens, who became a major influence on his work. Van Dyck worked in London for some months in 1621, then returned to Flanders for a brief time, before travelling to Italy, where he stayed until 1627, mostly in Genoa. In the late 1620s he completed his greatly admired ''Iconography'' se ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ferric Ammonium Citrate
Ammonium ferric citrate (also known as ferric ammonium citrate or ammoniacal ferrous citrate) has the formula . The iron in this compound is trivalent. All three carboxyl groups and the central hydroxyl group of citric acid are deprotonated. A distinguishing feature of this compound is that it is very soluble in water, in contrast to ferric citrate which is not very soluble. In its crystal structure each moiety of citric acid has lost four protons. The deprotonated hydroxyl group and two of the carboxylate groups ligate to the ferric center, while the third carboxylate group coordinates with the ammonium. Uses Ammonium ferric citrate has a range of uses, including: * As a food ingredient, it has an INS number 381, and is used as an acidity regulator. Most notably used in the Scottish beverage Irn-Bru. * Water purification * As a reducing agent of metal salts of low activity like gold and silver * With potassium ferricyanide as part of the cyanotype photographic process * Used ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tartaric Acid
Tartaric acid is a white, crystalline organic acid that occurs naturally in many fruits, most notably in grapes but also in tamarinds, bananas, avocados, and citrus. Its salt (chemistry), salt, potassium bitartrate, commonly known as cream of tartar, develops naturally in the process of winemaking, fermentation. Potassium bitartrate is commonly mixed with sodium bicarbonate and is sold as baking powder used as a leavening agent in food preparation. The acid itself is added to foods as an antioxidant E-numbers, E334 and to impart its distinctive sour taste. Naturally occurring tartaric acid is a useful raw material in organic synthesis. Tartaric acid, an alpha-hydroxy-carboxylic acid, is diprotic acid, diprotic and aldaric acid, aldaric in acid characteristics and is a dihydroxyl derivative of succinic acid. History Tartaric acid has been known to winemakers for centuries. However, the chemical process for extraction was developed in 1769 by the Sweden, Swedish chemist Carl Wilhel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Silver Nitrate
Silver nitrate is an inorganic compound with chemical formula . It is a versatile precursor to many other silver compounds, such as those used in photography. It is far less sensitive to light than the halides. It was once called ''lunar caustic'' because silver was called ''luna'' by ancient alchemists who associated silver with the moon. In solid silver nitrate, the silver ions are three- coordinated in a trigonal planar arrangement. Synthesis and structure Albertus Magnus, in the 13th century, documented the ability of nitric acid to separate gold and silver by dissolving the silver. Indeed silver nitrate can be prepared by dissolving silver in nitric acid followed by evaporation of the solution. The stoichiometry of the reaction depends upon the concentration of nitric acid used. :3 Ag + 4 HNO3 (cold and diluted) → 3 AgNO3 + 2 H2O + NO :Ag + 2 HNO3 (hot and concentrated) → AgNO3 + H2O + NO2 The structure of silver nitrate has been examined by X-ray crystallography se ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ultraviolet Light
Ultraviolet radiation, also known as simply UV, is electromagnetic radiation of wavelengths of 10–400 nanometers, shorter than that of visible light, but longer than X-rays. UV radiation is present in sunlight and constitutes about 10% of the total electromagnetic radiation output from the Sun. It is also produced by electric arcs, Cherenkov radiation, and specialized lights, such as mercury-vapor lamps, tanning lamps, and black lights. The photons of ultraviolet have greater energy than those of visible light, from about 3.1 to 12 electron volts, around the minimum energy required to ionize atoms. Although long-wavelength ultraviolet is not considered an ionizing radiation because its photons lack sufficient energy, it can induce chemical reactions and cause many substances to glow or fluoresce. Many practical applications, including chemical and biological effects, are derived from the way that UV radiation can interact with organic molecules. These int ... [...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] |
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] |
Kallitype
Kallitype is a process for making photographic prints. Patented in 1889 by W. W. J. Nicol (1855-1929), the Kallitype print is an iron-silver process. A chemical process similar to the Van Dyke brown (printing), Van Dyke brown based on the use of a combination of ferric and silver salts. While Van Dyke brown and argyrotype use ferric ammonium citrate, the light-sensitive element used for the Kallitype is ferric oxalate. The use of ferric oxalate allows for both extended shadow definition (higher Dmax (scanners), DMAX) and contrast control. Many developing solutions can be used to give a different image color (brown, sepia, blue, maroon and black). Kallitype images generally have a richer tonal range than the cyanotype. These prints were popular in the 19th century, and then their popularity faded away. Sometimes known as "the poor man's platinum print", when the image is toned in platinum or palladium the result is nearly chemically identical to a true Platinotype. It is believed tha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ferric Oxalate
Ferric oxalate, also known as iron(III) oxalate, refers to inorganic compounds with the formula (H2O)x but could also refer to salts of 3-. (H2O)x are coordination polymers with varying degrees of hydration. The coordination complex with the formula 3- forms a variety of salts, a well-known example being potassium ferrioxalate. This article emphasizes the coordination polymers. Structure Tetrahydrate According to X-ray crystallography of the tetrahydrate , iron is octahedral. The oxalate ligands are bridging. Some through all four oxygen atoms, some with two oxygen atoms. Half of the water is lattice water, being situated between chains of Fe oxalates. Mössbauer spectrum of exhibits an isomer shift of 0.38 mm/s and a quadrupole splitting of 0.40 mm/s, suggesting a high spin in octahedral coordination. Production Ferric oxalate may be produced by reaction of iron(III) hydroxide and solution of oxalic acid: : Uses Dentistry Like many oxalates, ferric o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ammonium Ferric Citrate
Ammonium ferric citrate (also known as ferric ammonium citrate or ammoniacal ferrous citrate) has the formula . The iron in this compound is trivalent. All three carboxyl groups and the central hydroxyl group of citric acid are deprotonated. A distinguishing feature of this compound is that it is very soluble in water, in contrast to ferric citrate which is not very soluble. In its crystal structure each moiety of citric acid has lost four protons. The deprotonated hydroxyl group and two of the carboxylate groups ligate to the ferric center, while the third carboxylate group coordinates with the ammonium. Uses Ammonium ferric citrate has a range of uses, including: * As a food ingredient, it has an INS number 381, and is used as an acidity regulator. Most notably used in the Scottish beverage Irn-Bru. * Water purification * As a reducing agent of metal salts of low activity like gold and silver * With potassium ferricyanide as part of the cyanotype photographic process * Us ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photogram
A photogram is a Photography, photographic image made without a camera by placing objects directly onto the surface of a light-sensitive material such as photographic paper and then exposing it to light. The usual result is a negative shadow image that shows variations in tone that depends upon the transparency of the objects used. Areas of the paper that have received no light appear white; those exposed for a shorter time or through transparent or semi-transparent objects appear grey, while fully-exposed areas are black in the final print. The technique is sometimes called cameraless photography. It was used by Man Ray in his #Man Ray's 'rayographs', rayographs. Other artists who have experimented with the technique include László Moholy-Nagy, Christian Schad (who called them "Schadographs"), Imogen Cunningham and Pablo Picasso. Variations of the technique have also been used for scientific purposes, in shadowgraph studies of flow in transparent media and in high-speed Schl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
