Louis Jean Lumière (5 October 1864 Besançon – 6 June 1948, Bandol)[1] was a French engineer and industrialist who played a key role in the development of photography and cinema.
Louis Lumière | |
|---|---|
 | |
| Born | Louis Jean Lumière 5 October 1864 |
| Died | 6 June 1948 (aged 83) |
| Occupation | Engineer |
| Relatives | Auguste Lumière (brother) |
| Engineering career | |
| Projects | cinematograph |
| Awards |
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Early life and education[edit]
Lumière was one of four children of Claude-Antoine Lumière, a photographer and painter, and his wife Jeanne-Joséphine (née Costille). He attended the Martinière Technical School and placed first in his class.[1]
Career[edit]
At age 17, Lumière invented a new process for film development using a dry plate. This process was significantly successful for the family business, permitting the opening of a new factory with an eventual production of 15 million plates per year.[2] Thomas Edison's Kinetoscope inspired his and his brother's subsequent work on the cinematograph.[3]
Louis Lumière is most often associated with the name of his brother, Auguste Lumière, under the name of the Lumière brothers. This comparison is a little excessive with regard to the invention of the cinematograph, since in reality, Auguste failed in his attempt to manufacture the first machine, and passed it to his brother who made the invention succeed. On the other hand, Louis was the director of all the first animated photographic views of the Lumière Society, which Auguste sometimes attended only as an amateur actor (Le Repas de bébé, La Pêche aux poissons rouges, Démolition d'un mur, etc.). But the contract signed between the two brothers provided that they be systematically associated, both morally and financially, in all their work and discoveries.
https://en.wikipedia.org/wiki/Louis_Lumière
Auguste Marie Louis Nicolas Lumière (19 October 1862 – 10 April 1954)[1] was a French engineer, industrialist, biologist, and illusionist. During 1894–1895, he and his brother Louis invented an animated photographic camera and projection device, the cinematograph, which met with worldwide success.
Lumière was born in Besançon. He attended the Martinière Technical School and worked as a manager at the photographic company of his father, Claude-Antoine Lumière. He was invited to attend a demonstration of the Kinetoscope invented by Thomas Edison, which inspired his and his brother's work on the cinematograph.[2] The brothers screened their first film using this device in December 1895, and following the success of this initial venture opened a number of cinemas worldwide. However, Auguste was skeptical of the potential of the device, remarking "My invention can be exploited... as a scientific curiosity, but apart from that it has no commercial value whatsoever".[3]
After his work on the cinematograph Lumière began focusing on the biomedical field, becoming a pioneer in the use of X-rays to examine fractures. He also contributed to innovations in military aircraft, producing a catalytic heater to allow cold-weather engine starts.[3] He died in Lyon, aged 91.
Auguste Lumière | |
|---|---|
 | |
| Born | Auguste Marie Louis Nicolas Lumière 19 October 1862 |
| Died | 10 April 1954 (aged 91) |
| Occupation | Engineer |
| Relatives | Louis Lumière (brother) |
| Engineering career | |
| Projects | cinematograph |
| Awards | star on the Hollywood Walk of Fame (1960) |
https://en.wikipedia.org/wiki/Auguste_Lumière
The Lumière brothers (UK: /ˈluːmiɛər/, US: /ˌluːmiˈɛər/; French: [lymjɛːʁ]), Auguste Marie Louis Nicolas Lumière (19 October 1862 – 10 April 1954) and Louis Jean Lumière (5 October 1864 – 6 June 1948),[1][2] were manufacturers of photography equipment, best known for their Cinématographe motion picture system and the short films they produced between 1895 and 1905 which places them among the earliest filmmakers.
Their screening of a single film on 22 March 1895 for around 200 members of the "Society for the Development of the National Industry" in Paris was probably the first presentation of projected film. Their first commercial public screeningon 28 December 1895 for around 40 paying visitors and invited relations has traditionally been regarded as the birth of cinema. Either the techniques or the business models of earlier filmmakers proved to be less viable than the breakthrough presentations of the Lumières.
Auguste and Louis Lumière | |
|---|---|
 Auguste (left) and Louis (right) | |
| Born |
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| Died | |
| Resting place | New Guillotière Cemetery (location A6) |
| Alma mater | La Martiniere Lyon |
| Occupation | |
| Parent(s) |
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| Awards | Elliott Cresson Medal (1909) |
https://en.wikipedia.org/wiki/Auguste_and_Louis_Lumière
The Autochrome Lumière was an early color photography process patented in 1903[1] by the Lumière brothers in France and first marketed in 1907.[2] Autochrome was an additive color[3] "mosaic screen plate" process. It was the principal color photography process in use before the advent of subtractive color film in the mid-1930s.
Prior to the Lumière brothers, Louis Ducos du Hauron utilized the separation technique to create colour images on paper with screen plates, producing natural colours through superimposition, which would become the foundation of all commercial colour photography.[4] Descendants of photographer Antoine Lumière, inventors Louis and Auguste Lumière utilized Du Hauron's (1869) technique, which had already been improved upon by other inventors such as John Joly (1894) and James William McDonough (1896), making it possible to print photographic images in colour.[5] One of the most broadly used forms of colour photography in the early twentieth century, autochrome was recognized for its aesthetic appeal.
Autochrome is an additive color[6] "mosaic screen plate" process. The medium consists of a glass plate coated on one side with a random mosaic of microscopic grains of potato starch[7] dyed red-orange, green, and blue-violet (an unusual but functional variant of the standard red, green, and blue additive colors); the grains of starch act as color filters. Lampblack fills the spaces between grains, and a black-and-white panchromatic silver halide emulsion is coated on top of the filter layer.[citation needed]
Unlike ordinary black-and-white plates, the Autochrome was loaded into the camera with the bare glass side facing the lens so that the light passed through the mosaic filter layer before reaching the emulsion. The use of an additional special orange-yellow filter in the camera was required to block ultraviolet light and restrain the effects of violet and blue light, parts of the spectrum to which the emulsion was overly sensitive. Because of the light loss due to all the filtering, Autochrome plates required much longer exposures than black-and-white plates and films, which meant that a tripod or other stand had to be used and that it was not practical to photograph moving subjects.[8] The plate was reversal-processed into a positive transparency — that is, the plate was first developed into a negative image but not "fixed", then the silver forming the negative image was chemically removed, then the remaining silver halide was exposed to light and developed, producing a positive image.[citation needed]
The luminance filter (silver halide layer) and the mosaic chrominance filter (the colored potato starch grain layer) remained precisely aligned and were distributed together, so that light was filtered in situ. Each starch grain remained in alignment with the corresponding microscopic area of silver halide emulsion coated over it. When the finished image was viewed by transmitted light, each bit of the silver image acted as a micro-filter, allowing more or less light to pass through the corresponding colored starch grain, recreating the original proportions of the three colors. At normal viewing distances, the light coming through the individual grains blended together in the eye, reconstructing the color of the light photographed through the filter grains.[citation needed]
To create the Autochrome color filter mosaic, a thin glass plate was first coated with a transparent adhesive layer. The dyed starch grains were graded to between 5 and 10 micrometers in size and the three colors were thoroughly intermingled in proportions which made the mixture appear gray to the unaided eye. They were then spread onto the adhesive, creating a layer with approximately 4,000,000 grains per square inch but only one grain thick. The exact means by which significant gaps and overlapping grains were avoided still remains unclear. It was found that the application of extreme pressure would produce a mosaic that more efficiently transmitted light to the emulsion, because the grains would be flattened slightly, making them more transparent, and pressed into more intimate contact with each other, reducing wasted space between them. As it was impractical to apply such pressure to the entire plate all at once, a steamroller approach was used which flattened only one very small area at a time. Lampblack was used to block up the slight spaces that remained. The plate was then coated with shellac to protect the moisture-vulnerable grains and dyes from the water-based gelatin emulsion, which was coated onto the plate after the shellac had dried. The resulting finished plate was cut up into smaller plates of the desired size, which were packaged in boxes of four. Each plate was accompanied by a thin piece of cardboard colored black on the side facing the emulsion. This was to be retained when loading and exposing the plate and served both to protect the delicate emulsion and to inhibit halation.
The 1906 U.S. patent describes the process more generally: the grains can be orange, violet, and green, or red, yellow, and blue (or "any number of colors"), optionally with black powder filling the gaps. Experimentations within the early twentieth century provided solutions to many issues, including the addition of screen plates, a yellow filter designed to balance the blue, and adjustments to the size of the silver halide crystals to allow for a broader spectrum of colour and control over the frequency of light.[9]
Because the presence of the mosaic color screen made the finished Autochrome image very dark overall, bright light and special viewing arrangements were needed for satisfactory results.
Stereoscopic Autochromes were especially popular, the combined color and depth proving to be a bewitching experience to early 20th Century eyes. Usually of a small size, they were most commonly viewed in a small hand-held box-type stereoscope. Larger, non-stereoscopic plates were most commonly displayed in a diascope, which was a folding case with the Autochrome image and a ground glass diffuser fitted into an opening on one side, and a mirror framed into the other side. The user would place the diascope near a window or other light source so that light passed through the diffuser and the Autochrome, and the resulting back-lit, dark-surrounded image would be viewed in the mirror. Slide projectors, then known as magic lanterns and stereopticons, were a less common but especially effective display technique, more suitable for public exhibitions. Unfortunately, projection required an extremely bright and therefore hot light source (a carbon arc or a 500 watt bulb were typical) and could visibly "fry" the plate if continued for more than two or three minutes, causing serious damage to the color.[10] More than a few surviving Autochromes suffer from such "tanning" and conventional projection is not a recommended means of displaying these irreplaceable images today.
However, a projector-like optical system (i.e., using condenser lenses for illumination, with a viewing lens in place of the projection lens), employing daylight (not direct sunlight) for the light source, can produce comparably excellent visual results—although for only one viewer at a time—without the unacceptable hazards of actual projection.
The use of a "light box" or similar highly diffused artificial light source for viewing Autochromes, although now nearly universal, is unfortunate, as the heavy scattering of light within and among the several layers of coatings on the plate degrades the color saturation. The slight pinkish tinge caused by colloidal scattering (the effect seen through a glass of water into which a couple of drops of milk have been mixed) is exacerbated, and the use of artificial light—especially fluorescent light—upsets the color rendition of a system which the Lumière Brothers carefully balanced for use with natural daylight.
Making modern film or digital copies of Autochromes introduces other problems, because a color system based on red, green, and blue is used to copy an image that exists within the red-orange, green, and blue-violet system, providing further opportunities for color degradation. Vintage reproductions of Autochromes in old books and magazines have often been noticeably hand-adjusted by the photoengravers in an effort to compensate for some of the difficulties of reproduction, and as a result they sometimes look more like hand-colored photographs than "natural color" ones. In short, it is very difficult to form an accurate impression of the appearance of any Autochrome image without seeing the original "in person" and correctly illuminated.
The lamination of the grains, varnish and emulsion makes autochrome plates susceptible to deterioration with each layer being vulnerable to changes in environment including moisture, oxidation, cracking, or flaking as well as physical damage from handling; Solutions include conservative lighting conditions, chemical free materials, medium-range humidity control of between 63 and 68 degrees Fahrenheit, and a well designed preservation plan.[11]
https://en.wikipedia.org/wiki/Autochrome_Lumière
Carbon black (subtypes are acetylene black, channel black, furnace black, lamp black and thermal black) is a material produced by the incomplete combustion of heavy petroleum products such as FCC tar, coal tar, ethylene cracking tar, or vegetable matter. Carbon black is a form of paracrystalline carbon that has a high surface-area-to-volume ratio, albeit lower than that of activated carbon. It is dissimilar to soot in its much higher surface-area-to-volume ratio and significantly lower (negligible and non-bioavailable) polycyclic aromatic hydrocarbon (PAH) content. However, carbon black is widely used as a model compound for diesel soot for diesel oxidation experiments.[2][better source needed]Carbon black is mainly used as a reinforcing filler in tires and other rubber products. In plastics, paints, and inks, carbon black is used as a color pigment.[3] It is used in some places, such as the EU, as a food colourant if produced from vegetable matter (E153).
The current International Agency for Research on Cancer (IARC) evaluation is that, "Carbon black is possibly carcinogenic to humans (Group 2B)".[4] Short-term exposure to high concentrations of carbon black dust may produce discomfort to the upper respiratory tract, through mechanical irritation.
| Names | |
|---|---|
| Other names Acetylene black; Channel black; Furnace black; Lamp black; Thermal black; C.I. Pigment Black 6 |
https://en.wikipedia.org/wiki/Carbon_black
A stereoscope is a device for viewing a stereoscopic pair of separate images, depicting left-eye and right-eye views of the same scene, as a single three-dimensional image.
A typical stereoscope provides each eye with a lens that makes the image seen through it appear larger and more distant and usually also shifts its apparent horizontal position, so that for a person with normal binocular depth perception the edges of the two images seemingly fuse into one "stereo window". In current practice, the images are prepared so that the scene appears to be beyond this virtual window, through which objects are sometimes allowed to protrude, but this was not always the custom. A divider or other view-limiting feature is usually provided to prevent each eye from being distracted by also seeing the image intended for the other eye.
Most people can, with practice and some effort, view stereoscopic image pairs in 3D without the aid of a stereoscope, but the physiological depth cues resulting from the unnatural combination of eye convergence and focus required will be unlike those experienced when actually viewing the scene in reality, making an accurate simulation of the natural viewing experience impossible and tending to cause eye strain and fatigue.
Although more recent devices such as Realist-format 3D slide viewers and the View-Master are also stereoscopes, the word is now most commonly associated with viewers designed for the standard-format stereo cards that enjoyed several waves of popularity from the 1850s to the 1930s as a home entertainment medium.
Devices such as polarized, anaglyph and shutter glasses which are used to view two actually superimposed or intermingled images, rather than two physically separate images, are not categorized as stereoscopes.
https://en.wikipedia.org/wiki/Stereoscope
The magic lantern, also known by its Latin name laterna magica, is an early type of image projector that used pictures—paintings, prints, or photographs—on transparent plates (usually made of glass), one or more lenses, and a light source. It was mostly developed in the 17th century and commonly used for entertainment purposes. It was increasingly used for education during the 19th century. Since the late 19th century, smaller versions were also mass-produced as toys. The magic lantern was in wide use from the 18th century until the mid-20th century when it was superseded by a compact version that could hold many 35 mm photographic slides: the slide projector.
https://en.wikipedia.org/wiki/Magic_lantern
A stereopticon is a slide projector or relatively powerful "magic lantern", which has two lenses, usually one above the other, and has mainly been used to project photographic images. These devices date back to the mid 19th century,[1] and were a popular form of entertainment and education before the advent of moving pictures.
Magic lanterns originally used rather weak light sources, like candles or oil lamps, that produced projections that were just large and strong enough to entertain small groups of people. During the 19th century stronger light sources, like limelight, became available.
For the "dissolving views" lantern shows that were popularized by Henry Langdon Childe since the late 1830s, lanternists needed to be able to project two aligned pictures in the same spot on a screen, gradually dimming a first picture while revealing a second one. This could be done with two lanterns, but soon biunial lanterns (with two objectives placed one above the other) became common.
William and Frederick Langenheim from Philadelphia introduced a photographic glass slide technology at the Crystal PalaceExhibition in London in 1851. For circa two centuries magic lanterns had been used to project painted images from glass slides, but the Langenheim brothers seem to have been the firsts to incorporate the relatively new medium of photography (introduced in 1839).[2] To enjoy the details of photographic slides optimally, the stronger lanterns were needed.
By 1860 Massachusetts chemist and businessman John Fallon improved a large biunial lantern, imported from England, and named it ‘stereopticon’.[2]
For a usual fee of ten cents, people could view realistic images of nature, history, and science themes.[3] The two lenses are used to dissolve between images when projected. This "visual storytelling" with technology directly preceded the development of the first moving pictures.[4]
The term stereopticon has been widely misused to name a stereoscope. The stereopticon has not commonly been used for three-dimensional images.
https://en.wikipedia.org/wiki/Stereopticon
An arc lamp or arc light is a lamp that produces light by an electric arc (also called a voltaic arc).
The carbon arc light, which consists of an arc between carbon electrodes in air, invented by Humphry Davy in the first decade of the 1800s, was the first practical electric light.[1] It was widely used starting in the 1870s for street and large building lighting until it was superseded by the incandescent light in the early 20th century.[1] It continued in use in more specialized applications where a high intensity point light source was needed, such as searchlights and movie projectors until after World War II. The carbon arc lamp is now obsolete for most of these purposes, but it is still used as a source of high intensity ultraviolet light.
The term is now used for gas discharge lamps, which produce light by an arc between metal electrodes through a gas in a glass bulb. The common fluorescent lamp is a low-pressure mercury arc lamp.[2] The xenon arc lamp, which produces a high intensity white light, is now used in many of the applications which formerly used the carbon arc, such as movie projectors and searchlights.
Operation[edit]
An arc is the discharge that occurs when a gas is ionized. A high voltage is pulsed across the lamp to "ignite" or "strike" the arc, after which the discharge can be maintained at a lower voltage. The "strike" requires an electrical circuit with an igniter and a ballast. The ballast is wired in series with the lamp and performs two functions.
First, when the power is first switched on, the igniter/starter (which is wired in parallel across the lamp) sets up a small current through the ballast and starter. This creates a small magnetic field within the ballast windings. A moment later the starter interrupts the current flow from the ballast, which has a high inductance and therefore tries to maintain the current flow (the ballast opposes any change in current through it); it cannot, as there is no longer a 'circuit'. As a result, a high voltage appears across the ballast momentarily, to which the lamp is connected; therefore the lamp receives this high voltage across it which 'strikes' the arc within the tube/lamp. The circuit will repeat this action until the lamp is ionized enough to sustain the arc.
When the lamp sustains the arc, the ballast performs its second function, to limit the current to that needed to operate the lamp. The lamp, ballast and igniter are rating-matched to each other; these parts must be replaced with the same rating as the failed component or the lamp will not work.
The colour of the light emitted by the lamp changes as its electrical characteristics change with temperature and time. Lightning is a similar principle where the atmosphere is ionized by the high potential difference (voltage) between earth and storm clouds.
The temperature of the arc in an arc lamp can reach several thousand degrees Celsius. The outer glass envelope can reach 500 degrees Celsius, therefore before servicing one must ensure the bulb has cooled sufficiently to handle. Often, if these types of lamps are turned off or lose their power supply, one cannot restrike the lamp again for several minutes (called cold restrike lamps). However, some lamps (mainly fluorescent tubes/energy saving lamps) can be restruck as soon as they are turned off (called hot restrike lamps).
The Vortek water-wall plasma arc lamp, invented in 1975 by David Camm and Roy Nodwell at the University of British Columbia, Vancouver, Canada, made the Guinness Book of World Records in 1986 and 1993 as the most powerful continuously burning light source at over 300 kW or 1.2 million candle power.[3]
Carbon arc lamp[edit]
In popular use, the term arc lamp means carbon arc lamp only. In a carbon arc lamp, the electrodes are carbon rods in free air. To ignite the lamp, the rods are touched together, thus allowing a relatively low voltage to strike the arc.[1] The rods are then slowly drawn apart, and electric current heats and maintains an arc across the gap. The tips of the carbon rods are heated and the carbon vaporizes. The carbon vapor in the arc is highly luminous, which is what produces the bright light.[1]The rods are slowly burnt away in use, and the distance between them needs to be regularly adjusted in order to maintain the arc.[1]
Many ingenious mechanisms were invented to affect the distance automatically, mostly based on solenoids. In one of the simplest mechanically-regulated forms (which was soon superseded by more smoothly acting devices) the electrodes are mounted vertically. The current supplying the arc is passed in series through a solenoid attached to the top electrode. If the points of the electrodes are touching (as in start up) the resistance falls, the current increases and the increased pull from the solenoid draws the points apart. If the arc starts to fail the current drops and the points close up again.
The Yablochkov candle is a simple arc lamp without a regulator, but it has the drawbacks that the arc cannot be restarted (single use) and a limited lifetime of only a few hours.
History[edit]
The concept of carbon-arc lighting was first demonstrated by Humphry Davy in the early 19th century, but sources disagree about the year he first demonstrated it; 1802, 1805, 1807 and 1809 are all mentioned. Davy used charcoal sticks and a two-thousand-cell battery to create an arc across a 4-inch (100 mm) gap. He mounted his electrodes horizontally and noted that, because of the strong convection flow of air, the arc formed the shape of an arch. He coined the term "arch lamp", which was contracted to "arc lamp" when the devices came into common usage.[4]
In the late nineteenth century, electric arc lighting was in wide use for public lighting. The tendency of electric arcs to flicker and hiss was a major problem. In 1895, Hertha Ayrton wrote a series of articles for The Electrician, explaining that these phenomena were the result of oxygen coming into contact with the carbon rods used to create the arc.[5][6] In 1899, she was the first woman ever to read her own paper before the Institution of Electrical Engineers (IEE). Her paper was "The Hissing of the Electric Arc".[7]
The arc lamp provided one of the first commercial uses for electricity, a phenomenon previously confined to experiment, the telegraph, and entertainment.[8]
Carbon-arc lighting in the U.S.[edit]
In the United States, there were attempts to produce arc lamps commercially after 1850, but the lack of a constant electricity supply thwarted efforts. Thus electrical engineers began focusing on the problem of improving Faraday's dynamo. The concept was improved upon by a number of people including William Edwards Staite and Charles F. Brush. It was not until the 1870s that lamps such as the Yablochkov candle were more commonly seen. In 1877, the Franklin Institute conducted a comparative test of dynamo systems. The one developed by Brush performed best, and Brush immediately applied his improved dynamo to arc-lighting, an early application being Public Square in Cleveland, Ohio, on April 29, 1879.[9] Despite this, Wabash, Indiana claims to be the first city ever to be lit with "Brush Lights". Four of these lights became active there on March 31, 1880. Wabash, IN Wabash was a small enough city to be lit entirely by 4 lights, whereas the installation at Cleveland's Public Square only lit a portion of that larger city. Brush Lights, Cleveland In 1880, Brush established the Brush Electric Company.
The harsh and brilliant light was found most suitable for public areas, such as Cleveland's Public Square, being around 200 times more powerful than contemporary filament lamps.
The usage of Brush electric arc lights spread quickly. Scientific American reported in 1881 that the system was being used in:[10] 800 lights in rolling mills, steel works, shops, 1,240 lights in woolen, cotton, linen, silk, and other factories, 425 lights in large stores, hotels, churches, 250 lights in parks, docks, and summer resorts, 275 lights in railroad depots and shops, 130 lights in mines, smelting works, 380 lights in factories and establishments of various kinds, 1,500 lights in lighting stations, for city lighting, 1,200 lights in England and other foreign countries. A total of over 6,000 lights which are actually sold.
There were three major advances in the 1880s: František Křižík invented in 1880 a mechanism to allow the automatic adjustment of the electrodes. The arcs were enclosed in a small tube to slow the carbon consumption (increasing the life span to around 100 hours). Flame arc lamps were introduced where the carbon rods had metal salts (usually magnesium, strontium, barium, or calcium fluorides) added to increase light output and produce different colours.
In the U.S., patent protection of arc-lighting systems and improved dynamos proved difficult and as a result the arc-lighting industry became highly competitive. Brush's principal competition was from the team of Elihu Thomson and Edwin J. Houston. These two had formed the American Electric Corporation in 1880, but it was soon bought up by Charles A. Coffin, moved to Lynn, Massachusetts, and renamed the Thomson-Houston Electric Company. Thomson remained, though, the principal inventive genius behind the company patenting improvements to the lighting system. Under the leadership of Thomson-Houston's patent attorney, Frederick P. Fish, the company protected its new patent rights. Coffin's management also led the company towards an aggressive policy of buy-outs and mergers with competitors. Both strategies reduced competition in the electrical lighting manufacturing industry. By 1890, the Thomson-Houston company was the dominant electrical manufacturing company in the U.S.[11] Nikola Tesla received U.S. Patent 447920, "Method of Operating Arc-Lamps" (March 10, 1891), that describes a 10,000 cycles per second alternator to suppress the disagreeable sound of power-frequency harmonics produced by arc lamps operating on frequencies within the range of human hearing.
Around the turn of the century arc-lighting systems were in decline, but Thomson-Houston controlled key patents to urban lighting systems. This control slowed the expansion of incandescent lighting systems being developed by Thomas Edison's Edison General Electric Company. Conversely, Edison's control of direct current distribution and generating machinery patents blocked further expansion of Thomson-Houston. The roadblock to expansion was removed when the two companies merged in 1892 to form the General Electric Company.[11]
Arc lamps were used in some early motion-picture studios to illuminate interior shots. One problem was that they produce such a high level of ultra-violet light that many actors needed to wear sunglasses when off camera to relieve sore eyes resulting from the ultra-violet light. The problem was solved by adding a sheet of ordinary window glass in front of the lamp, blocking the ultra-violet.[citation needed] By the dawn of the "talkies", arc lamps had been replaced in film studios with other types of lights.[citation needed] In 1915, Elmer Ambrose Sperry began manufacturing his invention of a high-intensity carbon arc searchlight. These were used aboard warships of all navies during the 20th century for signaling and illuminating enemies.[12]In the 1920s, carbon arc lamps were sold as family health products, a substitute for natural sunlight.[13]
Arc lamps were superseded by filament lamps in most roles, remaining in only certain niche applications such as cinemaprojection, followspots, and searchlights. Even in these applications conventional carbon arc lamps are being pushed into obsolescence by xenon arc lamps, but were still being manufactured as spotlights at least as late as 1982[14] and are still manufactured for at least one purpose – simulating sunlight in "accelerated aging" machines intended to estimate how fast a material is likely to be degraded by environmental exposure.[15][16]
The practice of shipping and projecting motion pictures on 2000-foot reels, and employing "changeovers" between two projectors, was due to the carbon rods used in projector lamphouses having a lifespan of roughly 22 minutes (which corresponds to the amount of film in said reels when projected at 24 frames/second). The projectionist would replace the carbon rod when changing film reels. The two-projector changeover setup largely disappeared in the 1970s with the advent of xenon projector lamps, being replaced with single-projector platter systems, though films would continue to be shipped to cinemas on 2000-foot reels.
See also[edit]
https://en.wikipedia.org/wiki/Arc_lamp
A moonlight tower or moontower is a lighting structure designed to illuminate areas of a town or city at night.
The towers were popular in the late 19th century in cities across the United States and Europe;[citation needed] they were most common in the 1880s and 1890s. In some places they were used when standard street-lighting, using smaller, shorter, and more numerous lamps, was impractically expensive. In other places they were used in addition to gas street lighting. The towers were designed to illuminate areas often of several blocks at once, on the "high light" principle. Arc lamps, known for their exceptionally bright and harsh light, were the most common method of illumination. As incandescent electric street lighting became common, the prevalence of towers began to wane.
Austin, Texas[edit]
Austin, Texas, is the only city in the world known to still have moonlight towers. They are 165 feet (50 m) tall with foundations 15 feet (4.6 m) wide. The towers were manufactured in Indiana by Fort Wayne Electric Company and assembled on site.[1] In 1894, the City of Austin purchased 31 used towers from Detroit. A single tower cast light from six carbon arc lamps, illuminating a 1,500-foot (460 m) radius brightly enough to read a watch.[2]
In 1993, the city of Austin dismantled the towers and restored every bolt, turnbuckle and guy-wire as part of a $1.3 million project, the completion of which was celebrated in 1995 with a citywide festival.
https://en.wikipedia.org/wiki/Moonlight_tower
Shielded metal arc welding (SMAW), also known as manual metal arc welding (MMA or MMAW), flux shielded arc welding[1] or informally as stick welding, is a manual arc welding process that uses a consumable electrode covered with a flux to lay the weld.
An electric current, in the form of either alternating current or direct current from a welding power supply, is used to form an electric arc between the electrode and the metals to be joined. The workpiece and the electrode melts forming a pool of molten metal (weld pool) that cools to form a joint. As the weld is laid, the flux coating of the electrode disintegrates, giving off vapors that serve as a shielding gas and providing a layer of slag, both of which protect the weld area from atmospheric contamination.
Because of the versatility of the process and the simplicity of its equipment and operation, shielded metal arc welding is one of the world's first and most popular welding processes. It dominates other welding processes in the maintenance and repair industry, and though flux-cored arc welding is growing in popularity, SMAW continues to be used extensively in the construction of heavy steel structures and in industrial fabrication. The process is used primarily to weld iron and steels (including stainless steel) but aluminium, nickel and copperalloys can also be welded with this method.[2]
https://en.wikipedia.org/wiki/Shielded_metal_arc_welding
Artistic considerations[edit]
If an Autochrome was well made and has been well preserved, color values can be very good. The dyed starch grains are somewhat coarse, giving a hazy, pointillist effect, with faint stray colors often visible, especially in open light areas such as skies. The smaller the image, the more noticeable these effects are. Autochrome has been touted as "the colour of dreams."[12] The resulting "dream-like" impressionist quality may have been one reason behind the enduring popularity of the medium even after more starkly realistic color processes had become available.[citation needed]
Although difficult to manufacture and relatively expensive, Autochromes were relatively easy to use and were immensely popular among enthusiastic amateur photographers, at least among those who could bear the cost and were willing to sacrifice the convenience of black and white hand-held "snapshooting." Autochromes failed to sustain the initial interest of more serious "artistic" practitioners, largely due to their inflexibility. Not only did the need for diascopes and projectors make them extremely difficult to publicly exhibit, they allowed little in the way of the manipulation much loved by aficionados of the then-popular Pictorialistapproach.[13]
Advent of film-based versions[edit]
Autochromes continued to be produced as glass plates into the 1930s, when film-based versions were introduced, first Lumière Filmcolor sheet film in 1931, then Lumicolor roll film in 1933. Although these soon completely replaced glass plate Autochromes, their triumph was short-lived, as Kodak and Agfa soon began to produce multi-layer subtractive color films (Kodachrome and Agfacolor Neu respectively). Nevertheless, the Lumière products had a devoted following, above all in France, and their use persisted long after modern color films had become available. The final version, Alticolor, was introduced in 1952 and discontinued in 1955, marking the end of the nearly fifty-year-long public life of the Autochrome.[14]
Important Autochrome collections[edit]
Between 1909 and 1931, a collection of 72,000 autochrome photographs, documenting life at the time in 50 countries around the world, was created by French banker Albert Kahn. The collection, one of the biggest of its kind in the world, is housed in The Albert Kahn Museum (Musée Albert-Kahn) on the outskirts of Paris.[15]A new compilation of images from the Albert Kahn collection was published in 2008.[16] The National Geographic Society made extensive use of autochromes and other mosaic color screen plates for over twenty years. 15,000 original Autochrome plates are still preserved in the Society's archives. The collection contains unique photographs, including numerous Autochromes from Paris by Auguste Léon from 1925 and by W. Robert Moore from 1936 just before WWII.[citation needed]
In the U.S. Library of Congress's huge collection of American Pictorialist photographer Arnold Genthe's work, 384 of his autochrome plates were among the holdings as of 1955.[17]
The George Eastman Museum in Rochester, N.Y. has an extensive collection of early colour photography, including Louise Ducos Du Hauron's earliest autochrome images and materials used by the Lumière brothers.[citation needed]
Bassetlaw Museum in Retford, Nottinghamshire holds a collection of over 700 autochromes by Stephen Pegler. This includes a collection of over 100 plates purchased by the museum in 2017 thanks to the generosity of local individuals and organisations.[18] The images cover a range of subjects from still lifes, posed studies, local people and landscapes, and his travels abroad, and were taken between 1910 and the early 1930s. The Pegler collection of autochromes is thought to be the largest collection of autochromes by one photographer in Britain today.[19]
The Royal Horticultural Society, UK has among the earliest colour photographs of plants and gardens taken by amateur photographer William Van Sommer (1859 - 1941), including of RHS Garden Wisley taken around 1913.[20]
Commercial use[edit]
One of the first books published with color photography used this technique. The 12 volumes of "Luther Burbank: His Methods and Discoveries, Their Practical Application" included 1,260 color photographs and a chapter on how this process worked.[citation needed]
In the early 1900s Ethel Standiford-Mehlingan was an experimental photographer and artist and owner of the Standiford Studio in Louisville, Kentucky. She was commissioned by Louisville artist and art patron Eleanor Belknap Humphrey to create an autochrome diascope of her two oldest children. Both the autochrome photograph of the Humphrey children and the diascope mirror viewing device, which closes into itself in a leather-bound case similar in size and appearance to a book, are well preserved and still viewable in 2015. Ethel Standiford-Mehlingan later moved her Louisville enterprise Standiford Studios to Cleveland, Ohio[21] and it is not known if any other examples of her autochrome diascopes still exist.[citation needed]
Vladimír Jindřich Bufka was a pioneer and popularizer of Autochrome in Bohemia.[citation needed]
Neo-Autochromists[edit]
There has been a revival of interest in the process by some, including a few groups in France working with original Lumière machinery and notes. One such recreation is a series of images from 2008 by the French photographer Frédéric Mocellin.[22] The British multimedia artist Stuart Humphryes has helped popularise the medium via his autochrome enhancement work in magazines, newspapers and on-line platforms [23]
- Autochrome images
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https://en.wikipedia.org/wiki/Autochrome_Lumière
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