1.
Hot metal typesetting
–
In printing and typography, hot metal typesetting refers to technologies for typesetting text in letterpress printing. This method injects molten type metal into a mold that has the shape of one or more glyphs, the resulting sorts and slugs are later used to press ink onto paper. Two different approaches to mechanising typesetting were independently developed in the late 19th century, one, known as the Monotype composition caster system, produced texts with the aid of perforated paper-ribbons, all characters are cast separate. These machines could produce texts also in large-composition up to 24 point, the Super-caster, another machine produced by Monotype, was similar in function to the Thompson, Bath, pivotal and others casters but designed to produce single type for hand setting. The other approach was to cast complete lines as one slug, in this way headings could be produced to complement text produced on other machines. There is another difference between Monotype and all the slug-producing machines, a Monotype machine functions with a minimal set of matrices. Linecasters cannot function this way, and these systems need quite large magazines of matrices to be able to set a line of text with the usual character repetitions. The key feature of the Linotype is the use of molds which circulate through the machine in its various stages of operation, one type is a space band and the other is a letter matrix made of brass. The matrices are stored in one or more magazines on top of the machine while the bands are stored in a box closer to the keyboard. When the space band key near the keyboard is pressed, one of the space bands drops out of the box, the assembling elevator is adjustable for different lengths of line. Once the line approaches its correct length, the operator is aware of this by a bell or other indicator. If the line is ‘tight’ or too long, the carrying the matrices. Both scenarios, if not stopped by these safety features, usually result in a “squirt” of molten metal, encasing the matrices. Not only is it time-consuming to clean up after a squirt, therefore, it is considered very poor form for an operator to permit this to happen. When the line is assembled to the length, the operator presses down on a lever which raises the assembling elevator up into the delivery channel. The delivery channel transfers the matrices out of the assembler and into the first elevator, if the justification bar has made a full cycle and the line is still not fully justified, the second safety—the pump stop—prevents the plunger in the metal pot from going down. The space bands were an important feature of this machine, providing automatic justification of each line by equally adjusting the space between each word. Since the type used was proportional and not fixed in width, some later models had a feature that permitted the lines to be cast with the alignment to either left, right or centered
Hot metal typesetting
–
Row of Linotype operators at the Chicago Defender newspaper, 1941
2.
William Fox Talbot
–
His work in the 1840s on photomechanical reproduction led to the creation of the photoglyphic engraving process, the precursor to photogravure. He was the holder of a patent which affected the early development of commercial photography in Britain. He was also a photographer who contributed to the development of photography as an artistic medium. He published The Pencil of Nature, which was illustrated with original salted paper prints from his calotype negatives, and made important early photographs of Oxford, Paris, Reading. Talbot was the child of William Davenport Talbot, of Lacock Abbey, near Chippenham, Wiltshire. Talbot was educated at Rottingdean, Harrow School and at Trinity College, Cambridge, where he was awarded the Porson Prize in Classics in 1820, from 1822 to 1872, he communicated papers to the Royal Society, many of them on mathematical subjects. At an early period, he began optical researches, which bore fruit in connection with photography. At a meeting of the Royal Institution on 25 January 1839, within a fortnight, he communicated the general nature of his process to the Royal Society, followed by more complete details a few weeks later. Daguerre did not publicly reveal any details until mid-August, although by the spring it had become clear that his process. In the case of images, that could require an exposure of an hour or two if something more than a silhouette of objects against a bright sky was wanted. This reduced the exposure time in the camera to only a minute or two for subjects in bright sunlight. The simpler salted paper process was used when making prints from calotype negatives. Talbot announced his calotype process in 1841, and in August he licensed Henry Collen, the most celebrated practitioners of the process were Hill & Adamson. Another notable calotypist was Levett Landon Boscawen Ibbetson, in 1842, Talbot received the Rumford Medal of the Royal Society for his photographic discoveries. In 1852, Talbot discovered that gelatine treated with potassium dichromate and this later provided the basis for the important carbon printing process and related technologies. Dichromated gelatine is still used for some laser holography, Talbots later photographic work was concentrated on photomechanical reproduction methods. Talbot created the engraving process, later perfected by others as the photogravure process. Daguerres work on his process had commenced at about the time as Talbots earliest work on his salted paper process
William Fox Talbot
–
William Henry Fox Talbot, by John Moffat, 1864.
William Fox Talbot
–
Latticed window at
Lacock Abbey, August 1835. A positive from what may be the oldest existing camera negative.
William Fox Talbot
–
Miss Horatia Feilding, half-sister of Talbot, playing the harp, c. 1842
William Fox Talbot
–
Talbot (far right) at the commercial establishment in Reading, 1846
3.
Paper
–
Paper is a thin material produced by pressing together moist fibres of cellulose pulp derived from wood, rags or grasses, and drying them into flexible sheets. It is a material with many uses, including writing, printing, packaging, cleaning. The modern pulp and paper industry is global, with China leading its production, the oldest known archaeological fragments of the immediate precursor to modern paper, date to the 2nd century BC in China. The pulp papermaking process is ascribed to Cai Lun, a 2nd-century AD Han court eunuch, with paper as an effective substitute for silk in many applications, China could export silk in greater quantity, contributing to a Golden Age. Because of papers introduction to the West through the city of Baghdad, in the 19th century, industrial manufacture greatly lowered its cost, enabling mass exchange of information and contributing to significant cultural shifts. In 1844, the Canadian inventor Charles Fenerty and the German F. G. Keller independently developed processes for pulping wood fibres, before the industrialisation of the paper production the most common fibre source was recycled fibres from used textiles, called rags. The rags were from hemp, linen and cotton, a process for removing printing inks from recycled paper was invented by German jurist Justus Claproth in 1774. Today this method is called deinking and it was not until the introduction of wood pulp in 1843 that paper production was not dependent on recycled materials from ragpickers. The word paper is etymologically derived from Latin papyrus, which comes from the Greek πάπυρος, although the word paper is etymologically derived from papyrus, the two are produced very differently and the development of the first is distinct from the development of the second. Papyrus is a lamination of natural plant fibres, while paper is manufactured from fibres whose properties have changed by maceration. To make pulp from wood, a chemical pulping process separates lignin from cellulose fibres and this is accomplished by dissolving lignin in a cooking liquor, so that it may be washed from the cellulose, this preserves the length of the cellulose fibres. Paper made from chemical pulps are also known as wood-free papers–not to be confused with paper, this is because they do not contain lignin. The pulp can also be bleached to produce paper, but this consumes 5% of the fibres, chemical pulping processes are not used to make paper made from cotton. There are three main chemical pulping processes, the process dates back to the 1840s and it was the dominant method extent before the second world war. Most pulping operations using the process are net contributors to the electricity grid or use the electricity to run an adjacent paper mill. Another advantage is that this process recovers and reuses all inorganic chemical reagents, soda pulping is another specialty process used to pulp straws, bagasse and hardwoods with high silicate content. There are two major mechanical pulps, thermomechanical pulp and groundwood pulp, in the TMP process, wood is chipped and then fed into steam heated refiners, where the chips are squeezed and converted to fibres between two steel discs. In the groundwood process, debarked logs are fed into grinders where they are pressed against rotating stones to be made into fibres
Paper
–
Different types of paper:
carton,
tissue paper
Paper
–
Hemp wrapping paper, China, circa 100 BC.
Paper
–
The microscopic structure of paper:
Micrograph of paper
autofluorescing under
ultraviolet illumination. The individual fibres in this sample are around 10
µm in diameter.
Paper
–
Card and paper stock for
crafts use comes in a wide variety of textures and colors.
4.
Silver iodide
–
Silver iodide is an inorganic compound with the formula AgI. The compound is a yellow solid, but samples almost always contain impurities of metallic silver that give a gray coloration. The silver contamination arises because AgI is highly photosensitive and this property is exploited in silver-based photography. Silver iodide is used as an antiseptic and in cloud seeding. The structure adopted by silver iodide is temperature dependent, Below 420 K and this phase is encountered in nature as the mineral iodargyrite. Above 420 K, the α-phase becomes more stable and this motif is a body-centered cubic structure which has the silver centers distributed randomly between 6 octahedral,12 tetrahedral and 24 trigonal sites. At this temperature, Ag+ ions can move rapidly through the solid, the transition between the β and α forms represents the melting of the silver sublattice. The entropy of fusion for α-AgI is approximately half that for sodium chloride and this can be rationalized by considering the AgI crystalline lattice to have already partly melted in the transition between α and β polymorphs. A metastable γ-phase also exists below 420 K with the zinc blende structure, silver iodide is prepared by reaction of an iodide solution with a solution of silver ions. The solid is a mixture of the two principal phases, dissolution of the AgI in hydroiodic acid, followed by dilution with water precipitates β-AgI. Alternatively, dissolution of AgI in a solution of concentrated silver nitrate followed by dilution affords α-AgI, if the preparation is not conducted in the absence of sunlight, the solid darkens rapidly, the light causing the reduction of ionic silver to metallic. The photosensitivity varies with sample purity, the crystalline structure of β-AgI is similar to that of ice, allowing it to induce freezing by the process known as heterogeneous nucleation. Approximately 50,000 kg are used for cloud seeding annually, extreme exposure can lead to argyria, characterized by localized discoloration of body tissue
Silver iodide
–
The golden-yellow crystals on this mineral sample are
iodargyrite, a naturally occurring form of β-AgI.
Silver iodide
Silver iodide
–
Cessna 210 equipped with a silver iodide generator for cloud seeding
5.
Greek language
–
Greek is an independent branch of the Indo-European family of languages, native to Greece and other parts of the Eastern Mediterranean. It has the longest documented history of any living language, spanning 34 centuries of written records and its writing system has been the Greek alphabet for the major part of its history, other systems, such as Linear B and the Cypriot syllabary, were used previously. The alphabet arose from the Phoenician script and was in turn the basis of the Latin, Cyrillic, Armenian, Coptic, Gothic and many other writing systems. Together with the Latin texts and traditions of the Roman world, during antiquity, Greek was a widely spoken lingua franca in the Mediterranean world and many places beyond. It would eventually become the official parlance of the Byzantine Empire, the language is spoken by at least 13.2 million people today in Greece, Cyprus, Italy, Albania, Turkey, and the Greek diaspora. Greek roots are used to coin new words for other languages, Greek. Greek has been spoken in the Balkan peninsula since around the 3rd millennium BC, the earliest written evidence is a Linear B clay tablet found in Messenia that dates to between 1450 and 1350 BC, making Greek the worlds oldest recorded living language. Among the Indo-European languages, its date of earliest written attestation is matched only by the now extinct Anatolian languages, the Greek language is conventionally divided into the following periods, Proto-Greek, the unrecorded but assumed last ancestor of all known varieties of Greek. The unity of Proto-Greek would have ended as Hellenic migrants entered the Greek peninsula sometime in the Neolithic era or the Bronze Age, Mycenaean Greek, the language of the Mycenaean civilisation. It is recorded in the Linear B script on tablets dating from the 15th century BC onwards, Ancient Greek, in its various dialects, the language of the Archaic and Classical periods of the ancient Greek civilisation. It was widely known throughout the Roman Empire, after the Roman conquest of Greece, an unofficial bilingualism of Greek and Latin was established in the city of Rome and Koine Greek became a first or second language in the Roman Empire. The origin of Christianity can also be traced through Koine Greek, Medieval Greek, also known as Byzantine Greek, the continuation of Koine Greek in Byzantine Greece, up to the demise of the Byzantine Empire in the 15th century. Much of the written Greek that was used as the language of the Byzantine Empire was an eclectic middle-ground variety based on the tradition of written Koine. Modern Greek, Stemming from Medieval Greek, Modern Greek usages can be traced in the Byzantine period and it is the language used by the modern Greeks, and, apart from Standard Modern Greek, there are several dialects of it. In the modern era, the Greek language entered a state of diglossia, the historical unity and continuing identity between the various stages of the Greek language is often emphasised. Greek speakers today still tend to regard literary works of ancient Greek as part of their own rather than a foreign language and it is also often stated that the historical changes have been relatively slight compared with some other languages. According to one estimation, Homeric Greek is probably closer to demotic than 12-century Middle English is to modern spoken English, Greek is spoken by about 13 million people, mainly in Greece, Albania and Cyprus, but also worldwide by the large Greek diaspora. Greek is the language of Greece, where it is spoken by almost the entire population
Greek language
–
Idealized portrayal of
Homer
Greek language
–
regions where Greek is the official language
Greek language
–
Greek language road sign, A27 Motorway, Greece
6.
Thomas Duncan (painter)
–
Thomas Duncan ARA RSA was a Scottish portrait and historical painter. Duncan was born in Kinclaven, Perthshire on 4 May 1807, educated at the Perth Academy, he began studying law, but abandoned it for art. In the 1830s his address is given as 1 Darnaway Street and he died in Edinburgh on 25 April 1845. He is buried in Warriston Cemetery in north Edinburgh, the grave lies on a slope next to the steps at the east end of the vaults (next to the grave of James Young Simpson. In the same year he produced his picture of Charles Edward asleep after Culloden, protected by Flora MacDonald, in 1844 appeared his Cupid, and his Martyrdom of John Brown of Priesthill. His last work was a self-portrait, now in the National Gallery in Edinburgh and he particularly excelled in his portraits of ladies and children, yet his own portrait was painted by Robert Scott Lauder. This article incorporates text from a now in the public domain, Chisholm, Hugh. Profile on Royal Academy of Arts Collections
Thomas Duncan (painter)
–
Thomas Duncan, by
Hill & Adamson, about 1844; medium:
calotype print, size: 19.60 x 14.50 cm; from the collection of the
National Galleries of Scotland
Thomas Duncan (painter)
–
Rev
Thomas Chalmers by Thomas Duncan 1840
Thomas Duncan (painter)
–
1 Darnaway Street, Edinburgh
Thomas Duncan (painter)
–
The grave of Thomas Duncan, Warriston Cemetery
7.
Silver chloride
–
Silver chloride is a chemical compound with the chemical formula AgCl. This white crystalline solid is known for its low solubility in water. Upon illumination or heating, silver chloride converts to silver, which is signaled by greyish or purplish coloration to some samples, AgCl occurs naturally as a mineral chlorargyrite. Silver chloride is synthesized by combining aqueous solutions of silver nitrate. AgNO3 + NaCl ⟶ AgCl ↓ + NaNO3 The solid adopts the fcc NaCl structure, however, the crystallography depends on the condition of crystallization, primarily free silver ion concentration, as is shown on the pictures left. AgCl dissolves in solutions containing ligands such as chloride, cyanide, triphenylphosphine, thiosulfate, thiocyanate, most complexes derived from AgCl are two-, three-, and, in rare cases, four-coordinate, adopting linear, trigonal planar, and tetrahedral coordination geometries, respectively. Due to its conspicuousness it is used in titration, which gives the typical case of argentometry. The solubility product, Ksp, for AgCl in water is 1. 77×10−10 at room temperature, ions that interfere with this test are bromide and iodide, as well as a variety of ligands. For AgBr and AgI, the Ksp values are 5.2 x 10−13 and 8.3 x 10−17, silver bromide and silver iodide are also significantly more photosensitive than is AgCl. AgCl quickly darkens on exposure to light by disintegrating into elemental chlorine and this reaction is used in photography and film. The silver chloride electrode is a reference electrode in electrochemistry. Silver chlorides low solubility makes it an addition to pottery glazes for the production of Inglaze lustre. Silver chloride has been used as an antidote for poisoning, assisting in the elimination of mercury
Silver chloride
–
Silver Chloride Crystals
Silver chloride
Silver chloride
–
Pyramidal Crystals of AgCl
Silver chloride
–
Silver chloride decomposes over time with exposure to UV light
8.
Negative (photography)
–
In the case of color negatives, the colors are also reversed into their respective complementary colors. Typical color negatives have a dull orange tint due to an automatic color-masking feature that ultimately results in improved color reproduction. Negatives are normally used to make prints on photographic paper by projecting the negative onto the paper with a photographic enlarger or making a contact print. The paper is also darkened in proportion to its exposure to light, so a second reversal results which restores light, negatives were once commonly made on a thin sheet of glass rather than a plastic film, and some of the earliest negatives were made on paper. It is incorrect to call an image a negative solely because it is on a transparent material, transparent prints can be made by printing a negative onto special positive film, as is done to make traditional motion picture film prints for use in theaters. Some films used in cameras are designed to be developed by reversal processing, positives on film or glass are known as transparencies or diapositives, and if mounted in small frames designed for use in a slide projector or magnifying viewer they are commonly called slides. A positive image is a normal image, a negative image is a total inversion, in which light areas appear dark and vice versa. A negative color image is additionally color-reversed, with red areas appearing cyan, greens appearing magenta and blues appearing yellow, film negatives usually have less contrast, but a wider dynamic range, than the final printed positive images. The contrast typically increases when they are printed onto photographic paper, when negative film images are brought into the digital realm, their contrast may be adjusted at the time of scanning or, more usually, during subsequent post-processing. Film for cameras that use the 35 mm still format is sold as a strip of emulsion-coated and perforated plastic spooled in a light-tight cassette. Before each exposure, a mechanism inside the camera is used to pull an unexposed area of the out of the cassette. When all exposures have been made the strip is rewound into the cassette, after the film is chemically developed, the strip shows a series of small negative images. It is usually cut into sections for easier handling. Each of these images may be referred to as a negative. They are the images, from which all positive prints will derive. However, when an image is created from a negative image a positive image results. This makes most chemical-based photography a two-step process, which uses negative film, special films and development processes have been devised so that positive images can be created directly on the film, these are called positive, or slide, or reversal films and reversal processing. Scanning film negatives at the Wayback Machine NegaTIV -. -
Negative (photography)
–
Color positive picture (A) and negative (B), monochrome positive picture (C) and negative (D)
9.
Daguerreotype
–
Daguerreotype process, or daguerreotypy, was the first publicly available photographic process, and for nearly twenty years it was the one most commonly used. During the past few decades, there has been a revival of daguerreotypy among photographers interested in making artistic use of early photographic processes. The darkest areas of the image are simply bare silver, lighter areas have a microscopically fine light-scattering texture, the surface is very delicate, and even the lightest wiping can permanently scuff it. Some tarnish around the edges is normal, the name daguerreotype correctly refers only to one very specific image type and medium, the product of a process that was in wide use only from the early 1840s to the late 1850s. Since the Renaissance era, artists and inventors had searched for a method of capturing visual scenes. Later, with the advent of Modernism, the absence of perspective in art from China, Japan. To copy these images was the first object of Mr. Daguerre met with Niépce, Niépce had invented an early internal combustion engine together with his brother Claude and made improvements to the velocipede, as well as experimenting with lithography and related processes. Their correspondence reveals that Niépce was at first reluctant to any details of his work with photographic images. To guard against letting any secrets out before the invention had been improved,15, for example, signified the tanning action of the sun on human skin,34 - a camera obscura,74 - sulphuric acid. Niépce undertook to release details of the process he had invented - the asphalt process or heliography, Daguerre was sworn to secrecy under penalty of damages, and undertook to design a camera and improve the process. The improved process was named the physautotype. Niépces early experiments had derived from his interest in lithography, the asphalt process, or heliography required exposures that were so long that Arago said it was not fit for use. Nevertheless, without Niépces experiments, it is unlikely that Daguerre would have been able to build on them to adapt, after Niépces death in 1833, his son, Isidore, inherited rights in the contract and a new version was drawn up between Daguerre and Isidore. It would bear Daguerres name alone and this was the daguerreotype process that used iodized silvered plates and was developed with mercury fumes. To exploit the invention four hundred shares would be on offer for a thousand francs each, or, the rights of the process could be bought for twenty thousand francs. Everyone says it is superb, but it will cost us the thousand francs before we learn it and be able to judge if it could remain secret. M. de Mandelot himself knows several persons who could subscribe but will not do so because they think it would be revealed by itself, and now I have proof that many think in this way. I entirely agree with the idea of M. Arago, that is get the government to purchase this discovery, nevertheless, he benefited from the state pension awarded to him together with Daguerre
Daguerreotype
–
Daguerreotype of
Louis Daguerre in 1844 by Jean-Baptiste Sabatier-Blot
Daguerreotype
–
1840–1841
Camerae obscurae and plates for Daguerreotype called "Grand Photographe" produced by Charles Chevalier (
Musée des Arts et Métiers)
Daguerreotype
–
Still life with plaster casts, made by Daguerre in 1837, the earliest reliably dated daguerreotype
Daguerreotype
10.
Latent image
–
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, in more physical terms, a latent image is a small cluster of metallic silver atoms formed in or on a silver halide crystal due to reduction of interstitial silver ions by photoelectrons. If intense exposure continues, such photolytic silver clusters grow to visible sizes and this is called printing out the image. On the other hand, the formation of an image by the action of photographic developer is called developing out the image. The size of a cluster in the latent image can be as small as a few silver atoms. However, in order to act as a latent image center. On the other hand, a developed silver grain can have billions of silver atoms, therefore, photographic developer acting on the latent image is a chemical amplifier with a gain factor up to several billion. The development system was the most important technology that increased the sensitivity in the history of photography. The action of the light on the silver halide grains within the emulsion forms sites of metallic silver in the grains, the basic mechanism by which this happens was first proposed by R W Gurney and N F Mott in 1938. The incoming photon liberates an electron, called a photoelectron, from a silver halide crystal, photoelectrons migrate to a shallow electron trap site, where the electrons reduce silver ions to form a metallic silver speck. A positive hole must also be generated but it is largely ignored, subsequent work has slightly modified this picture, so that hole trapping is also considered. Since then, understanding of the mechanism of sensitivity and latent image formation has been greatly improved, one very important way to increase photographic sensitivity is to manipulate the electron traps in each crystal. A pure, defect-free crystal exhibits poor photographic sensitivity, since it lacks a shallow electron trap that facilitates the formation of a latent image, in such a case, many of the photoelectrons will recombine with the silver halide crystal and be wasted. Shallow electron traps are created by sulfur sensitization, introduction of a crystalline defect, the location, kind and number of shallow traps have a huge influence on the efficiency by which the photoelectrons create latent image centers, and consequently, on photographic sensitivity. Another important way to increase photographic sensitivity is to reduce the size of developable latent images. Gold sensitization of Koslowski creates metallic gold specks on the crystal surface, when a latent image is formed around the gold speck, the presence of gold is known to reduce the number of metallic silver atoms necessary to render the crystal developable. Another important concept in increasing photographic sensitivity is to separate photoholes away from photoelectrons and this should reduce the probability of recombination. Reduction sensitization is one implementation of this concept
Latent image
–
"Printed out" image on a 35mm B&W film, overexposed by approximately 24 stops (about two days of exposure at f/2), without any chemical processing, showing that the silver clusters can grow up to visible sizes without developing.
11.
Photographic processing
–
Photographic processing or development is the chemical means by which photographic film or paper is treated after photographic exposure to produce a negative or positive image. Photographic processing transforms the latent image into an image, makes this permanent. All processes based upon the process are similar, regardless of the film or papers manufacturer. Exceptional variations include instant films such as made by Polaroid. Kodachrome required Kodaks proprietary K-14 process, Kodachrome film production ceased in 2009, and K-14 processing is no longer available as of December 30,2010. Ilfochrome materials use the dye destruction process, all photographic processing use a series of chemical baths. Processing, especially the development stages, requires very close control of temperature, agitation, the film may be soaked in water to swell the gelatin layer, facilitating the action of the subsequent chemical treatments. The developer converts the latent image to macroscopic particles of metallic silver, a stop bath, † typically a dilute solution of acetic acid or citric acid, halts the action of the developer. A rinse with water may be substituted. The fixer makes the image permanent and light-resistant by dissolving remaining silver halide, a common fixer is hypo, specifically ammonium thiosulfate. Washing in clean water removes any remaining fixer, residual fixer can corrode the silver image, leading to discolouration, staining and fading. The washing time can be reduced and the more completely removed if a hypo clearing agent is used after the fixer. Film may be rinsed in a solution of a non-ionic wetting agent to assist uniform drying. Film is then dried in an environment, cut and placed into protective sleeves. Once the film is processed, it is referred to as a negative. The negative may now be printed, the negative is placed in an enlarger, many different techniques can be used during the enlargement process. Two examples of enlargement techniques are dodging and burning, alternatively, the negative may be scanned for digital printing or web viewing after adjustment, retouching, and/or manipulation. † In modern automatic processing machines, the bath is replaced by mechanical squeegee or pinching rollers
Photographic processing
–
Black and white negative processing is the chemical means by which photographic film and paper is treated after photographic exposure to produce a negative or positive image. Photographic processing transforms the latent image into a visible image, makes this permanent and renders it insensitive to light.
Photographic processing
–
A cut-away illustration of a typical light-trap tank used in small scale developing.
12.
Silver halide
–
A silver halide is one of the chemical compounds that can form between the element silver and one of the halogens. In particular, bromine, chlorine, iodine and fluorine may each combine with silver to silver bromide, silver chloride, silver iodide. As a group, they are referred to as the silver halides. Silver halides are light-sensitive chemicals, and are used in photographic film. The gelatin is a part of the emulsion as the protective colloid of appropriate physical and chemical properties. Gelatin may also contain elements which increase the light sensitivity of the emulsion. When a silver halide crystal is exposed to light, a sensitivity speck on the surface of the crystal is turned into a speck of metallic silver. If the speck of silver contains approximately four or more atoms, areas of the emulsion receiving larger amounts of light undergo the greatest development and therefore results in the highest optical density. Silver bromide and silver chloride may be used separately or combined, depending on the sensitivity, silver fluoride is not used in photography. Silver halides are used to make corrective lenses darken when exposed to ultraviolet light. Silver halides, except for silver fluoride, are insoluble in water. Silver nitrate can be used to precipitate halides, this application is useful in analysis of halides. The three main silver halide compounds have distinctive colours that can be used to quickly identify halide ions in a solution, the silver chloride compound forms a white precipitate, silver bromide a creamy coloured precipitate and silver iodide a yellow coloured precipitate. However, close attention is necessary for other compounds in the test solution, some compounds can considerably increase or decrease the solubility of AgX. Examples of compounds that increase the solubility include, cyanide, thiocyanate, thiosulfate, thiourea, amines, ammonia, sulfite, thioether, scientists from Tel Aviv University are experimenting with silver halide optical fibers for transmitting mid-infrared light from carbon dioxide lasers. The fibers allow laser welding of human tissue, as an alternative to traditional sutures
Silver halide
–
The three common silver halide precipitates:
AgI,
AgBr &
AgCl (left to right)
13.
Silver nitrate
–
Silver nitrate is an inorganic compound with chemical formula AgNO3. This compound is a precursor to many other silver compounds. It is far less sensitive to light than the halides and it was once called lunar caustic because silver was called luna by the ancient alchemists, who believed that silver was associated with the moon. In solid silver nitrate, the ions are three-coordinated in a trigonal planar arrangement. Albertus Magnus, in the 13th century, documented the ability of nitric acid to separate gold, Magnus noted that the resulting solution of silver nitrate could blacken skin. Silver nitrate can be prepared by reacting silver, such as a silver bullion or silver foil, with acid, resulting in silver nitrate, water. Reaction byproducts depend upon the concentration of acid used. 3 Ag +4 HNO3 →3 AgNO3 +2 H2O + NO Ag +2 HNO3 → AgNO3 + H2O + NO2 This is performed under a fume hood because of nitrogen oxide evolved during the reaction. A typical reaction with silver nitrate is to suspend a rod of copper in a solution of silver nitrate, silver nitrate is the least expensive salt of silver, it offers several other advantages as well. It is non-hygroscopic, in contrast to silver fluoroborate and silver perchlorate and it is relatively stable to light. Finally, it dissolves in solvents, including water. The nitrate can be replaced by other ligands, rendering AgNO3 versatile. Treatment with solutions of halide ions gives a precipitate of AgX, similarly, silver nitrate is used to prepare some silver-based explosives, such as the fulminate, azide, or acetylide, through a precipitation reaction. This reaction is used in inorganic chemistry to abstract halides, Ag+ + X− → AgX where X− = Cl−, Br−. Other silver salts with non-coordinating anions, namely silver tetrafluoroborate and silver hexafluorophosphate are used for demanding applications. Similarly, this reaction is used in chemistry to confirm the presence of chloride, bromide. Samples are typically acidified with nitric acid to remove interfering ions, e. g. carbonate ions. This step avoids confusion of silver sulfide or silver carbonate precipitates with that of silver halides, the color of precipitate varies with the halide, white, pale yellow/cream, yellow
Silver nitrate
Silver nitrate
–
Silver nitrate
Silver nitrate
–
Micrograph showing a silver nitrate (brown) marked
surgical margin.
Silver nitrate
–
Skin on hand stained by silver nitrate
14.
Potassium iodide
–
Potassium iodide is a chemical compound, medication, and dietary supplement. As a medication it is used to treat hyperthyroidism, in radiation emergencies, in the developing world it is also used to treat skin sporotrichosis and phycomycosis. As a supplement it is used in those who have low intake of iodine in the diet, common side effects include vomiting, diarrhea, abdominal pain, rash, and swelling of the salivary glands. Other side effects include allergic reactions, headache, goitre, while use during pregnancy may harm the baby this use is still recommended in radiation emergencies. Potassium iodide has the chemical formula KI, commercially it is made by mixing potassium hydroxide with iodine. Potassium iodide has been used medically since at least 1820 and it is on the World Health Organizations List of Essential Medicines, the most effective and safe medicines needed in a health system. Potassium iodide is available as a medication and over the counter. In the United States a course of treatment is less than 25 USD, potassium iodide is also used for the iodization of salt. The major uses of KI include as a supplement in animal feeds. For the latter, it is the most common used to iodize table salt. The oxidation of iodide causes slow loss of content from iodised salts that are exposed to excess air. The alkali metal salt, over time and exposure to excess oxygen and carbon dioxide, slowly oxidizes to metal carbonate and elemental iodine. Potassium iodate is used to add iodine to some salts so that the iodine is not lost by oxidation, dextrose or sodium thiosulfate are often added to iodized table salt to stabilize potassium iodide thus reducing loss of the volatile chemical. These compounds contain iodine, but not in the iodide form, U. S. However, some sources recommend alternative dosing regimens. Iodine-131 iobenguane used for therapeutic purposes requires a different pre-medication duration, beginning 24–48 hours prior to iobenguane injection, in 1982, the U. S. Food and Drug Administration approved potassium iodide to protect thyroid glands from radioactive iodine involving accidents or fission emergencies. In an accidental event or attack on a power plant, or in nuclear bomb fallout. Of these products, 131I is one of the most common and is dangerous to the thyroid gland because it may lead to thyroid cancer. By saturating the body with a source of stable iodide prior to exposure, inhaled or ingested 131I tends to be excreted, according to one 2000 study KI administered up to 48 h before 131I exposure can almost completely block thyroid uptake and therefore greatly reduce the thyroid absorbed dose
Potassium iodide
–
Potassium iodide
Potassium iodide
–
Pheochromocytoma seen as dark sphere in center of the body. Image is by
MIBG scintigraphy with radiation from radioiodine in the MIBG. However, note unwanted uptake of radioiodine from the pharmaceutical by the thyroid gland in the neck, in both images (front and back) of the same patient. Radioactivity is also seen in the bladder.
15.
Gallic acid
–
Gallic acid is a trihydroxybenzoic acid, a type of phenolic acid, found in gallnuts, sumac, witch hazel, tea leaves, oak bark, and other plants. The chemical formula of gallic acid is C6H23COOH and it is found both free and as part of hydrolyzable tannins. The gallic acid groups are bonded to form dimers such as ellagic acid. Hydrolyzable tannins break down on hydrolysis to give gallic acid and glucose or ellagic acid and glucose, known as gallotannins and ellagitannins, gallic acid forms intermolecular esters such as digallic and trigallic acids, and cyclic ether-esters. Gallic acid can also be used as a material in the synthesis of the psychedelic alkaloid mescaline. The name is derived from oak galls, which were used to prepare tannic acid. Despite the name, gallic acid does not contain gallium, salts and esters of gallic acid are termed gallates. Pliny the Elder describes his experiments with it and writes that it was used to produce dyes, galls from oak trees were crushed and mixed with water, producing tannic acid. Gallic acid was one of the used by Angelo Mai, among other early investigators of palimpsests, to clear the top layer of text off. Mai was the first to employ it, but did so with a heavy hand, gallic acid was first studied by the Swedish chemist Carl Wilhelm Scheele in 1786. Gallic acid is a component of some pyrotechnic whistle mixtures, gallic acid is formed from 3-dehydroshikimate by the action of the enzyme shikimate dehydrogenase to produce 3, 5-didehydroshikimate. This latter compound tautomerizes to form the redox equivalent gallic acid, gallate dioxygenase is an enzyme found in Pseudomonas putida that catalyses the reaction gallate + O2 → -4-oxobut-1-ene-1,2, 4-tricarboxylate. Gallate decarboxylase is another enzyme in the degradation of gallic acid, gallate 1-beta-glucosyltransferase is an enzyme that uses UDP-glucose and gallate, whereas its two products are UDP and 1-galloyl-beta-D-glucose. It is a carbonic anhydrase inhibitor. In basic research, gallic acid extracted from seeds has been shown to inhibit the formation of amyloid fibrils, one of the potential causes of Alzheimers disease. One study indicated that gallic acid has this effect on amyloid protein formation by modifying the properties of alpha-synuclein, gallic acid is classified as a mutagen and a teratogen. Gallic acid is found in a number of plants, such as the parasitic plant Cynomorium coccineum, the aquatic plant Myriophyllum spicatum. Gallic acid is found in various oak species, Caesalpinia mimosoides
Gallic acid
16.
Potassium bromide
–
Potassium bromide is a salt, widely used as an anticonvulsant and a sedative in the late 19th and early 20th centuries, with over-the-counter use extending to 1975 in the US. Its action is due to the bromide ion, potassium bromide is used as a veterinary drug, as an antiepileptic medication for dogs. Under standard conditions, potassium bromide is a crystalline powder. It is freely soluble in water, it is not soluble in acetonitrile, in a dilute aqueous solution, potassium bromide tastes sweet, at higher concentrations it tastes bitter, and tastes salty when the concentration is even higher. These effects are due to the properties of the potassium ion—sodium bromide tastes salty at any concentration. In high concentration, potassium bromide strongly irritates the mucous membrane, causing nausea. Potassium bromide, an ionic salt, is fully dissociated. It serves as a source of bromide ions, bromide can be regarded as the first effective medication for epilepsy. At the time, it was thought that epilepsy was caused by masturbation. Locock noted that bromide calmed sexual excitement and thought this was responsible for his success in treating seizures, there was not a better epilepsy drug until phenobarbital in 1912. Bromides exceedingly long life in the body made it difficult to dose without side effects. Medical use of bromides in the US was discontinued at this time, as many better, use of bromide in cats is limited because it carries a substantial risk of causing lung inflammation in them. Potassium bromide is not approved by the US Food and Drug Administration for use in humans to control seizures, in Germany, it is still approved as an antiepileptic drug for humans, particularly children and adolescents. These indications include severe forms of generalized tonic-clonic seizures, early-childhood-related Grand-Mal-seizures, adults who have reacted positively to the drug during childhood/adolescence may continue treatment. Potassium bromide tablets are sold under the brand name Dibro-Be mono, the drug has almost complete bioavailability, but the bromide ion has a relatively long half life of 12 days in the blood, making bromide salts difficult to adjust and dose. The therapeutic index for bromide is small, as with other antiepileptics, sometimes even therapeutic doses may give rise to intoxication. Often indistinguishable from expected side-effects, these include, Bromism These are central nervous system reactions, rarely, tongue disorder, aphten, bad breath, and obstipation occur. Potassium bromide is transparent from the ultraviolet to long-wave infrared wavelengths and has no significant optical absorption lines in its high transmission region
Potassium bromide
–
Potassium bromide
Potassium bromide
–
A bottle of PRN Pharmaceutical Company (Pensacola, FL) K•BroVet veterinary pharmaceutical potassium bromide oral solution (250 mg/mL). The product is intended to be used in dogs, primarily as an
antiepileptic (to stop seizures). The pink color of the solution is artificial; pure potassium bromide solutions are colorless
17.
Silver bromide
–
Silver bromide, a soft, pale-yellow, water-insoluble salt well known for its unusual sensitivity to light. This property has allowed silver halides to become the basis of modern photographic materials, AgBr is widely used in photographic films and is believed by some to have been used for making the Shroud of Turin. The salt can be found naturally as the mineral bromargyrite, modern preparation of a simple, light-sensitive surface involves forming an emulsion of silver halide crystals in a gelatine, which is then coated onto a film or other support. The crystals are formed by precipitation in an environment to produce small. The coordination geometry for AgBr in the NaCl structure is unexpected for Ag which typically forms linear, unlike the other silver halides, iodargyrite contains a hexagonal zincite lattice structure. The silver halides have a range of solubilities. The solubility of AgF is about 6 ×107 times that of AgI and these differences are attributed to the relative solvation enthalpies of the halide ions, the enthalpy of solvation of fluoride is anomalously large. Although photographic processes have been in development since the mid-1800s, there were no suitable theoretical explanations until 1938 with the publication of a paper by R. W. Gurney and N. F. This paper triggered a large amount of research in fields of chemistry and physics. Further research into this mechanism revealed that the properties of silver halides were a result of deviations from an ideal crystal structure. What is unique about AgBr Frenkel pairs is that the interstitial Agi+ are exceptionally mobile, the formation energy of the Frenkel pair is low at 1.16 eV, and the migration activation energy is unusually low at 0.05 eV. These low energies result in large concentrations, which can reach near 1% near the melting point. The low activation energy in silver bromide can be attributed the silver ions’ high quadrupolar polarizability and this property, a result of the d9 electronic configuration of the silver ion, facilitates migration in both the silver ion and in silver-ion vacancies, thus giving the unusually low migration energy. Studies have demonstrated that the concentrations are strongly affected by crystal size. Most defects, such as interstitial silver ion concentration and surface kinks, are proportional to crystal size. This phenomenon is attributed to changes in the surface chemistry equilibrium, impurity concentrations can be controlled by crystal growth or direct addition of impurities to the crystal solutions. After this point, only silver-ion vacancy defects, which increase by several orders of magnitude, are prominent. When a photoelectron is mobilized, a photohole h• is also formed, the lifetime of a photohole, however, does not correlate with that of a photoelectron
Silver bromide
18.
Sodium thiosulphate
–
Sodium thiosulfate, also spelled sodium thiosulphate, is a chemical and medication. As a medication it is used to treat cyanide poisoning and pityriasis versicolor and it is an inorganic compound that is typically available as the pentahydrate, Na2S2O3·5H2O. The solid is an efflorescent crystalline substance that dissolves well in water and it is also called sodium hyposulfite or “hypo”. It is on the World Health Organizations List of Essential Medicines and it is used as an antidote to cyanide poisoning. Thiosulfate serves as a donor for the conversion of cyanide to thiocyanate. For this purpose it is used together with sodium nitrite and it has been used as treatment of calciphylaxis in hemodialysis people with end-stage kidney disease. There is apparently an incompletely understood phenomenon whereby this causes severe metabolic acidosis in some patients, in foot baths for prophylaxis of ringworm, and as a topical antifungal agent for tinea versicolor. It is used in the management of extravasations during chemotherapy, Sodium thiosulfate prevents alkylation and tissue destruction by providing a substrate for the alkylating agents that have invaded the subcutaneous tissues. The dose may be 2 ml of 0.17 M and it may be instilled subcutaneously into multiple sites using a small-gauge needle. Data are limited on this method with few recommendations, in measuring the volume of extracellular body fluid and the renal glomerular filtration rate. Na2S2O3·5H2O is also a component of iodine clock experiments and this particular use can be set up to measure the oxygen content of water through a long series of reactions in the Winkler test for dissolved oxygen. It is also used in estimating volumetrically the concentrations of compounds in solution. Silver halides, e. g. Sodium thiosulfate is a component of an alternative lixiviant to cyanide for extraction of gold, however, it forms a strong soluble complex with gold ions, 3−. The advantage of this approach is that thiosulfate is essentially not toxic, the reduction reaction is analogous to the iodine reduction reaction. In pH testing of substances, sodium thiosulfate neutralizes the color-removing effects of bleach. The relevant reaction is akin to the reaction, thiosulfate reduces the hypochlorite. The complete reaction is,4 NaClO + Na2S2O3 +2 NaOH →4 NaCl +2 Na2SO4 + H2O Similarly, sodium reacts with bromine. Solutions of sodium thiosulfate are commonly used as a precaution in chemistry laboratories when working with bromine and for the disposal of bromine, iodine
Sodium thiosulphate
Sodium thiosulphate
–
Sodium thiosulfate
19.
Translucent
–
In the field of optics, transparency is the physical property of allowing light to pass through the material without being scattered. On a macroscopic scale, the photons can be said to follow Snells Law, in other words, a translucent medium allows the transport of light while a transparent medium not only allows the transport of light but allows for image formation. The opposite property of translucency is opacity, transparent materials appear clear, with the overall appearance of one color, or any combination leading up to a brilliant spectrum of every color. When light encounters a material, it can interact with it in different ways. These interactions depend on the wavelength of the light and the nature of the material, photons interact with an object by some combination of reflection, absorption and transmission. Some materials, such as glass and clean water, transmit much of the light that falls on them and reflect little of it. Many liquids and aqueous solutions are highly transparent, absence of structural defects and molecular structure of most liquids are mostly responsible for excellent optical transmission. Materials which do not transmit light are called opaque, many such substances have a chemical composition which includes what are referred to as absorption centers. Many substances are selective in their absorption of light frequencies. They absorb certain portions of the spectrum while reflecting others. The frequencies of the spectrum which are not absorbed are either reflected or transmitted for our physical observation and this is what gives rise to color. The attenuation of light of all frequencies and wavelengths is due to the mechanisms of absorption. Transparency can provide almost perfect camouflage for animals able to achieve it and this is easier in dimly-lit or turbid seawater than in good illumination. Many marine animals such as jellyfish are highly transparent, at the atomic or molecular level, physical absorption in the infrared portion of the spectrum depends on the frequencies of atomic or molecular vibrations or chemical bonds, and on selection rules. Nitrogen and oxygen are not greenhouse gases because there is no absorption because there is no molecular dipole moment. With regard to the scattering of light, the most critical factor is the scale of any or all of these structural features relative to the wavelength of the light being scattered. Primary material considerations include, Crystalline structure, whether or not the atoms or molecules exhibit the long-range order evidenced in crystalline solids, glassy structure, scattering centers include fluctuations in density or composition. Microstructure, scattering centers include internal surfaces such as boundaries, crystallographic defects
Translucent
–
Dichroic filters are created using optically transparent materials.
Translucent
–
Translucency of a material being used to highlight the structure of a photographic subject
Translucent
–
Meiningen Catholic Church, 20th century glass
Translucent
–
A laser beam bouncing down an
acrylic rod, illustrating the total internal reflection of light in a multimode optical fiber
20.
Contact print
–
A contact print is a photographic image produced from film, sometimes from a film negative, and sometimes from a film positive. The defining characteristic of a print is that the resulting print is the same size as the original. One or more negatives are placed in contact with a sheet of sensitized photographic paper. The negative and the paper are then placed, negative side down. Within the box and below the top plate is a translucent light diffuser made from frosted glass, below the diffuser is a switch-controlled electric light source. A hinged top-cover keeps the materials in contact and reduces or eliminates the amount of stray light allowed into the darkroom. Ansel Adams describes procedures for making prints using ordinary lighting in his book. The contact printer is used to expose the image onto the paper for a few seconds. The operator may use a switch and count off the seconds himself. The black and white gelatin-silver process may be using a safelight for darkroom illumination. The contact printer may also contain a safelight so that the negative can be examined before the paper is laid upon it. After exposure, the paper is processed using chemicals in the darkroom to produce the final print, the paper must be placed in a film developer bath, a stop bath, fixer, and finally the hypo-eliminator bath, in that order. Failure to adhere precisely to this process will result in a poor-quality final image with a variety of issues, since this process produces neither enlargements nor reductions, the image on the print is exactly the same size as the image on the negative. For 120 roll film and larger film, contact prints are used to determine the final print size. In medium and large format photography, contact prints are prized for their fidelity to the negative. A disadvantage to using contact prints in the fine-arts is the laboriousness of modifying exposure selectively, however, the exposure value range, the variation from darkest to lightest regions, is inherently greater in negatives than in prints. When large format film is printed to create finished work, it is possible. Burning and dodging require painstaking work with masks, or the use of a production contact printing machine
Contact print
–
An example of a contact
print from small format film strips intended for image review.
Contact print
–
A 120 roll film proof sheet of
Diane Arbus ' containing her
Child with Toy Hand Grenade in Central Park from 1962
21.
Louis Daguerre
–
Louis-Jacques-Mandé Daguerre was a French artist and photographer, recognized for his invention of the daguerreotype process of photography. He became known as one of the fathers of photography, though he is most famous for his contributions to photography, he was also an accomplished painter and a developer of the diorama theatre. Louis Daguerre was born in Cormeilles-en-Parisis, Val-dOise, France and he was apprenticed in architecture, theatre design, and panoramic painting to Pierre Prévost, the first French panorama painter. Exceedingly adept at his skill of theatrical illusion, he became a designer for the theatre, and later came to invent the diorama. In 1829, Daguerre partnered with Nicéphore Niépce, an inventor who had produced the worlds first heliograph in 1822, Niépce died suddenly in 1833, but Daguerre continued experimenting, and evolved the process which would subsequently be known as the daguerreotype. After efforts to interest private investors proved fruitless, Daguerre went public with his invention in 1839, under assurances of strict confidentiality, Daguerre explained and demonstrated the process only to the Academys perpetual secretary François Arago, who proved to be an invaluable advocate. Members of the Academy and other individuals were allowed to examine specimens at Daguerres studio. The images were enthusiastically praised as nearly miraculous, and news of the daguerreotype quickly spread, in 1839, he was elected to the National Academy of Design as an Honorary Academician. Daguerre died on 10 July 1851 in Bry-sur-Marne,12 km from Paris, a monument marks his grave there. Daguerres name is one of the 72 names inscribed on the Eiffel tower, in the mid-1820s, prior to his association with Daguerre, Niépce used a coating of bitumen of Judea to make the first permanent camera photographs. The bitumen was hardened where it was exposed to light and the portion was then removed with a solvent. A camera exposure lasting for hours or days was required, Niépce and Daguerre later refined this process, but unacceptably long exposures were still needed. After the death of Niépce in 1833, Daguerre concentrated his attention on the properties of silver salts. The plate was exposed in the camera. Upon seeing the image, the contents of which are unknown, Daguerre said, the latent image on a daguerreotype plate was developed by subjecting it to the vapor given off by mercury heated to 75 °C. The resulting visible image was then fixed by removing the silver iodide with concentrated and heated salt water. Later, a solution of the more effective hypo was used instead, the resultant plate produced an exact reproduction of the scene. The image was laterally reversed—as images in mirrors are—unless a mirror or inverting prism was used during exposure to flip the image, daguerreotypes were usually portraits, the rarer landscape views and other unusual subjects are now much sought-after by collectors and sell for much higher prices than ordinary portraits
Louis Daguerre
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Louis Daguerre
Louis Daguerre
–
"
Boulevard du Temple ", taken by Daguerre in 1838 in Paris, includes the earliest known candid photograph of a person. The image shows a street, but because of the over ten-minute exposure time the moving traffic does not appear. At the lower left, however, a man apparently having his boots polished, and the
bootblack polishing them, were motionless enough for their images to be captured.
Louis Daguerre
–
An engraving of Daguerre during his career
Louis Daguerre
–
The Ruins of Holyrood Chapel.
22.
Patent
–
A patent is a set of exclusive rights granted by a sovereign state to an inventor or assignee for a limited period of time in exchange for detailed public disclosure of an invention. An invention is a solution to a technological problem and is a product or a process. Patents are a form of intellectual property, the procedure for granting patents, requirements placed on the patentee, and the extent of the exclusive rights vary widely between countries according to national laws and international agreements. Typically, however, a patent application must include one or more claims that define the invention. A patent may include many claims, each of which defines a specific property right and these claims must meet relevant patentability requirements, such as novelty, usefulness, and non-obviousness. Nevertheless, there are variations on what is patentable subject matter from country to country, the word patent originates from the Latin patere, which means to lay open. More directly, it is a version of the term letters patent. Similar grants included land patents, which were land grants by early state governments in the USA, and printing patents, a precursor of modern copyright. In modern usage, the term patent usually refers to the granted to anyone who invents any new, useful. The additional qualification utility patent is used to distinguish the primary meaning from these other types of patents. Particular species of patents for inventions include biological patents, business method patents, chemical patents, the period of protection was 10 years. These were mostly in the field of glass making, as Venetians emigrated, they sought similar patent protection in their new homes. This led to the diffusion of patent systems to other countries, by the 16th century, the English Crown would habitually abuse the granting of letters patent for monopolies. After public outcry, King James I of England was forced to revoke all existing monopolies, the Statute became the foundation for later developments in patent law in England and elsewhere. Important developments in patent law emerged during the 18th century through a process of judicial interpretation of the law. During the reign of Queen Anne, patent applications were required to supply a complete specification of the principles of operation of the invention for public access. Influenced by the philosophy of John Locke, the granting of patents began to be viewed as a form of property right. The English legal system became the foundation for patent law in countries with a common law heritage, including the United States, New Zealand, in the Thirteen Colonies, inventors could obtain patents through petition to a given colonys legislature
Patent
–
U.S patent
Patent
–
James Puckle 's 1718
early autocannon was one of the first inventions required to provide a specification for a patent.
Patent
–
The plate of the Martin
ejector seat of a military aircraft, stating that the design is covered by multiple patents in Britain, South Africa, Canada and "others".
Dübendorf Museum of Military Aviation.
23.
Salt print
–
The salt print was the dominant paper-based photographic process for producing positive prints during the period from 1839 through approximately 1860. The salted paper technique was created in the mid-1830s by English scientist and this produced a tenacious coating of silver chloride in an especially light-sensitive chemical condition. The paper darkened where it was exposed to light, in 1839, washing with a solution of sodium thiosulfate was found to be the most effective way to make the results truly light-fast. The salt print process is often confused with Talbots slightly later calotype or talbotype process and this made calotype paper far more practical for use in a camera. Salted paper typically required at least an hour of exposure in the camera to yield a negative showing much more than objects silhouetted against the sky
Salt print
–
Edinburgh Ale:
James Ballantine, Dr George Bell and David Octavius Hill by
Hill & Adamson, a salt print from a
calotype paper negative, ca. 1844
24.
Collodion process
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The collodion process is an early photographic process. Collodion is normally used in its wet form, but can also be used in humid or dry form, the latter 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. The collodion process is said to have invented in 1851, almost simultaneously, by Frederick Scott Archer. During the subsequent decades, many photographers and experimenters refined or varied the process, by the end of the 1850s it had almost entirely replaced the first practical photographic process, the daguerreotype. During the 1880s the collodion process, was replaced by gelatin dry plates—glass plates with a photographic emulsion of silver halides suspended in gelatin. The dry gelatin emulsion was not only convenient, but it could also be made much more sensitive. The wet plate collodion process has undergone a revival as a historical technique over the past few decades, there are several practising ambrotypists and tintypists who regularly set up and make images at Civil War re-enactments. Fine art photographers use the process and its handcrafted individuality for gallery showings, there are several makers of reproduction equipment. The process is taught in workshops around the world and several workbooks, many artists work with collodion around the globe, including traveling photographer Craig Murphy, Kurt Grüng, Sally Mann, and Ben Cauchi. The collodion process produced an image on a transparent support. The collodion process, thus combined desirable qualities of the calotype process, collodion printing was typically done on albumen paper. The collodion process had other advantages, especially in comparison with the daguerreotype and it was a relatively inexpensive process. The polishing equipment and fuming equipment needed for the daguerreotype could be dispensed with entirely, the support for the images was glass, which was far less expensive than silver-plated copper, and was more durable than paper negatives. It was also fast for the time, requiring only seconds for exposure, the wet collodion process had a major disadvantage. The entire process, from coating to developing, had to be done before the plate dried and this gave the photographer no more than 10 minutes to complete everything. This made it inconvenient for use, as it required a portable darkroom. The plate dripped silver nitrate solution, causing stains and troublesome build-ups in the camera, the silver nitrate bath was also a source of problems
Collodion process
–
An old deteriorated wet plate featuring
Theodore Roosevelt
Collodion process
–
A portable photography studio in 19th century Ireland. The wet collodion process sometimes gave rise to portable darkrooms, as photographic images needed to be developed while the plate was still wet.
Collodion process
–
Anonymous "A Veteran with his Wife", Hand Tinted Ambrotype - Wet Collodion Positive
25.
Photographic plate
–
Photographic plates preceded photographic film as a capture medium in photography. The light-sensitive emulsion of silver salts was coated on a plate, typically thinner than common window glass. Glass plates were far superior to film for research-quality imaging because they were stable and less likely to bend or distort. Early plates used the wet collodion process, the wet plate process was replaced late in the 19th century by gelatin dry plates. Glass plate photographic material largely faded from the market in the early years of the 20th century, as more convenient. Workshops on the use of glass plate photography as a medium or for artistic use are still being conducted. A number of observatories, including Harvard College and Sonneberg, maintain large archives of photographic plates, many solar system objects were discovered by using photographic plates, superseding earlier visual methods. Discovery of minor planets using photographic plates was pioneered by Max Wolf beginning with his discovery of 323 Brucia in 1891, the first natural satellite discovered using photographic plates was Phoebe in 1898. Glass-backed plates, rather than film, were used in astronomy because they do not shrink or deform noticeably in the development process or under environmental changes. Photographic plates were also an important tool in early high-energy physics, Photographic emulsions were originally coated on thin glass plates for imaging with electron microscopes, which provided a more rigid, stable and flatter plane compared to plastic films. Beginning in the 1970s, high-contrast, fine grain emulsions coated on thicker plastic films manufactured by Kodak, Ilford and these films have largely been replaced by digitally imaging technologies. The earliest flexible films of the late 1880s were sold for use in medium-format cameras. The plastic was not of high optical quality and tended to curl. Initially, a transparent plastic base was more expensive to produce than glass, quality was eventually improved, manufacturing costs came down, and most amateurs gladly abandoned plates for films. After large-format high quality cut films for professional photographers were introduced in the late 1910s, CCD cameras have several advantages over glass plates, including high efficiency, linear light response, and simplified image acquisition and processing. The manufacture of plates has been discontinued by Kodak, Agfa. In the realm of traditional photography, a number of historical process enthusiasts make their own wet or dry plates from raw materials. Several institutions have established archives to preserve photographic plates and prevent their valuable historical information from being lost, the emulsion on the plate can deteriorate
Photographic plate
–
AGFA photographic plates, 1880
Photographic plate
–
Mimosa Panchroma-Studio-Antihalo Panchromatic glass plates, 9 x 12cm, Mimosa A.-G. Dresden
Photographic plate
–
Negative plate
26.
Albumen print
–
During the mid-19th century, the carte de visite became one of the more popular uses of the albumen method. In the 19th century, E. & H. T. Anthony & Company were the largest makers and distributors of the Albumen photographic prints, a piece of paper, usually 100% cotton, is coated with an emulsion of egg white and salt, then dried. The albumen seals the paper and creates a slightly glossy surface for the sensitizer to rest on, the paper is then dipped in a solution of silver nitrate and water which renders the surface sensitive to UV light. The paper is then dried in the absence of UV light, the dried, prepared paper is placed in a frame in direct contact under a negative. The negative is traditionally a glass negative with collodion emulsion, but this step can be performed with a silver halide negative. The paper with negative is then exposed to light until the image achieves the level of darkness. Though direct sunlight was used long ago, a UV exposure unit is often used contemporarily because it is more predictable, a bath of sodium thiosulfate fixes the print’s exposure, preventing further darkening. Optional gold or selenium toning improves the photograph’s tone and stabilizes against fading, depending on the toner, toning may be performed before or after fixing the print. Because the image emerges as a result of exposure to light, without the aid of a developing solution. The table salt in the emulsion forms silver chloride when in contact with silver nitrate. Silver chloride is unstable when exposed to light, which makes it decompose into silver, the silver ion is reduced to silver by addition of an electron during the development/printing process, and the remaining silver chloride is washed out during fixing. The black parts of the image are formed by metallic silver, photography, the importance of its applications in preserving pictorial records. Containing a practical description of the Talbotype process, george Eastman House Photographic Process 3. Albumen printing, Creating and processing albumen paper, archived from the original on 2009-01-07
Albumen print
–
Louis Désiré Blanquart-Evrard in 1869, albumen print, by himself
Albumen print
–
The
Hypaethral Temple, Philae, by
Francis Frith, 1857; medium: albumen print, original size 38.2×49.0 cm; from the collection of the
National Galleries of Scotland
Albumen print
–
Camille Silvy 's albumen print of the suffragette and birth control proponent
Viscountess Amberley, original size 3 3/8 in. × 2 1/8 in. (85 mm × 55 mm)
27.
Ambrotype
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The ambrotype or amphitype, 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. One side of a glass plate was coated with a thin layer of iodized collodion. 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 camera lens. The plate was developed and fixed. The resulting negative, when viewed by reflected light against a background, appears to be a positive image, the clear areas look black. This effect was integrated by backing the plate with black velvet, by taking the picture on a made of dark reddish-colored glass. Either the emulsion side or the side could be coated, if the bare side was blackened. In either case, another plate of glass was put over the fragile emulsion side to protect it, in some instances the protective glass was cemented directly to the emulsion, generally with a balsam resin. This protected the well but tended to darken it. Ambrotypes were sometimes hand-tinted, untinted ambrotypes are monochrome, gray or tan in their lightest areas, the ambrotype was based on the wet plate collodion process invented by Frederick Scott Archer. Ambrotypes were deliberately underexposed negatives made by that process and optimized for viewing as positives instead, in the US, ambrotypes first came into use in the early 1850s. In 1854, James Ambrose Cutting of Boston took out several patents relating to the process and he may be responsible for coining the term ambrotype. An ambrotype, however, appeared dull and drab when compared with the brilliance of a well-made, by the late 1850s, the ambrotype was overtaking the daguerreotype in popularity. youtube. com/watch. v=Z1BtdiA1fDs
Ambrotype
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Many ambrotypes were made by unknown photographers, such as this American example of a Union soldier with his family, circa 1863-65. Because of their fragility ambrotypes were usually kept in folding cases like those used for
daguerreotypes. This example is framed for display.
Ambrotype
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Peninsular War veteran and his wife, c. 1860, with some hand-tinting
Ambrotype
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American actress
Charlotte Cushman, 1859
Ambrotype
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Bare ambrotype plate, c. 1860, showing damage to emulsion and varnish
28.
Tintype
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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 in the 21st. Because the lacquered iron support was resilient and did not need drying, the tintype photograph saw more uses and captured a wider variety of settings and subjects than any other photographic type. It was introduced while the daguerreotype was still popular, though its primary competition would have been the ambrotype, the tintype saw the Civil War come and go, documenting the individual soldier and horrific battle scenes. It captured scenes from the Wild West, as it was easy to produce by itinerant photographers working out of covered wagons. It began losing artistic and commercial ground to higher quality albumen prints on paper in the mid-1860s, yet survived for well over another 40 years, the tintypes immediate predecessor, the ambrotype, was done by the same process of using a sheet of glass as the support. The glass was either of a color or provided with a black backing so that, as with a tintype. Tintypes were sturdy and did not require mounting in a hard case like ambrotypes and daguerreotypes. There are two historic tintype processes, wet and dry, in the wet process, a collodion emulsion containing suspended silver halide crystals had to be formed on the plate just before it was exposed in the camera while still wet. Chemical treatment then reduced the crystals to microscopic particles of silver in proportion to the intensity and duration of their exposure to light. The later and more convenient dry process was similar but used a gelatin emulsion which could be applied to the plate long before use, in both processes, a very underexposed negative image was produced in the emulsion. Its densest areas, corresponding to the lightest parts of the subject, the image as a whole therefore appeared to be a dull-toned positive. This ability to employ underexposed images allowed shorter exposure times to be used, to obtain as light-toned an image as possible, potassium cyanide, a very dangerous and powerful deadly poison, was normally employed as the photographic fixer. It was perhaps the most acutely hazardous of all the highly toxic chemicals originally used in this. One unusual piece of equipment was a twelve-lensed camera that could make a dozen 3⁄4-by-1-inch gem portraits with one exposure. Portrait sizes ranged from gem-size to 11 in ×14 in, from about 1865 to 1910, the most popular size, called Bon-ton, ranged from 2 3⁄8 in ×3 1⁄2 in to 4 in ×5 3⁄4 in. Each tintype is usually a camera original, so the image is usually a mirror image, sometimes the camera was fitted with a mirror or right-angle prism so that the end result would be right-reading. The process was first described by Adolphe-Alexandre Martin in France in 1853, in 1856 it was patented by Hamilton Smith in the United States and by William Kloen in the United Kingdom. It was first called melainotype, then ferrotype by a manufacturer of the iron plates used
Tintype
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Tintype of two girls in front of a painted background of the Cliff House and Seal Rocks in San Francisco, c. 1900
29.
International Standard Book Number
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The International Standard Book Number is a unique numeric commercial book identifier. An ISBN is assigned to each edition and variation of a book, for example, an e-book, a paperback and a hardcover edition of the same book would each have a different ISBN. The ISBN is 13 digits long if assigned on or after 1 January 2007, the method of assigning an ISBN is nation-based and varies from country to country, often depending on how large the publishing industry is within a country. The initial ISBN configuration of recognition was generated in 1967 based upon the 9-digit Standard Book Numbering created in 1966, the 10-digit ISBN format was developed by the International Organization for Standardization and was published in 1970 as international standard ISO2108. Occasionally, a book may appear without a printed ISBN if it is printed privately or the author does not follow the usual ISBN procedure, however, this can be rectified later. Another identifier, the International Standard Serial Number, identifies periodical publications such as magazines, the ISBN configuration of recognition was generated in 1967 in the United Kingdom by David Whitaker and in 1968 in the US by Emery Koltay. The 10-digit ISBN format was developed by the International Organization for Standardization and was published in 1970 as international standard ISO2108, the United Kingdom continued to use the 9-digit SBN code until 1974. The ISO on-line facility only refers back to 1978, an SBN may be converted to an ISBN by prefixing the digit 0. For example, the edition of Mr. J. G. Reeder Returns, published by Hodder in 1965, has SBN340013818 -340 indicating the publisher,01381 their serial number. This can be converted to ISBN 0-340-01381-8, the check digit does not need to be re-calculated, since 1 January 2007, ISBNs have contained 13 digits, a format that is compatible with Bookland European Article Number EAN-13s. An ISBN is assigned to each edition and variation of a book, for example, an ebook, a paperback, and a hardcover edition of the same book would each have a different ISBN. The ISBN is 13 digits long if assigned on or after 1 January 2007, a 13-digit ISBN can be separated into its parts, and when this is done it is customary to separate the parts with hyphens or spaces. Separating the parts of a 10-digit ISBN is also done with either hyphens or spaces, figuring out how to correctly separate a given ISBN number is complicated, because most of the parts do not use a fixed number of digits. ISBN issuance is country-specific, in that ISBNs are issued by the ISBN registration agency that is responsible for country or territory regardless of the publication language. Some ISBN registration agencies are based in national libraries or within ministries of culture, in other cases, the ISBN registration service is provided by organisations such as bibliographic data providers that are not government funded. In Canada, ISBNs are issued at no cost with the purpose of encouraging Canadian culture. In the United Kingdom, United States, and some countries, where the service is provided by non-government-funded organisations. Australia, ISBNs are issued by the library services agency Thorpe-Bowker
International Standard Book Number
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A 13-digit ISBN, 978-3-16-148410-0, as represented by an
EAN-13 bar code
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