The Tri-Ergon sound-on-film system was developed from around 1919 by three German inventors, Josef Engl, Joseph Massolle, Hans Vogt. The system used a photoelectric recording method and a non-standard film size which incorporated the sound track with stock 35mm film. With a Swiss backer, the inventors formed Tri-Ergon AG in Zurich, tried to interest the market with their invention. There were a number of companies which used the Tri-Ergon name: Tri-Ergon AG, acquired the rights to the original 1919 patents from the inventors in 1923 Tri-Ergon-Musik AG, founded c1926, held the patents for the rest of the world outside Germany Tri-Ergon-Musik AG, which made phonograph records and owned the patents for Germany, formed in 1927: a subsidiary or branch of the St. Gallen company Tri-Ergon-Photo-Electro-Records, a record label subsidiary of Tri-Ergon-Musik AG Ufa acquired the German sound film rights for the Tri-Ergon process in 1925, but dropped the system when the public showing of their first sound film suffered technical failures.
The Tri-Ergon system appeared at a time when a number of other sound film processes were arriving on the market, the company soon merged with a number of competitors to form the Tobis syndicate in 1928, joined by the Klangfilm AG syndicate in 1929 and renamed as Tobis-Klangfilm by 1930. While Tri-Ergon became the dominant sound film process in Germany and much of Europe through its use by Tobis-Klangfilm, American film companies were still squabbling over their respective patents. For a time Tri-Ergon blocked all American attempts to show their sound films in Germany and other European countries, until a loose cartel was formed under an agreement in Paris in 1930. However, William Fox of the Fox Film Corporation acquired the US rights for the Tri-Ergon system and, backed by Tri-Ergon AG, began a patent infringement battle in the courts in 1929 against much of the American film industry; the dispute wasn't settled until 1935. A new Paris accord was signed in March 1936; the Tri-Ergon system continued in use in the continent during the war.
The name Tri-Ergon means "the work of three", is derived from Greek: τρία, translit. Tria, meaning three, ἔργον, érgon, meaning'deed, work, labour, or task'; the erg derives from the same word ἔργον. The Tri-Ergon process involved recording sound onto film using the "variable density" method, used by Movietone and Lee De Forest's Phonofilm, rather than the "variable area" method used by RCA Photophone. Tri-Ergon used a special form of microphone without mechanical moving parts for sound pickup and a special electric discharge tube for variable density film recording. For reproduction of sound, the system used an electrostatic loudspeaker. Two specific patents in the Tri-Ergon system would cause controversy; the Tri-Ergon film used an extra 7mm sound strip attached to the edge of a standard 35mm film, resulting in a new film 42mm wide. This was achieved by a "double-printing" method by which the film and sound tracks were recorded and developed separately printed together onto a common positive.
This required special adjustments on the standard projectors, not well received by the industry. The other patent was a "flywheel" which allowed the film to flow smoothly through sound reproducing equipment. An original Tri-Ergon sound movie projector is in the collection of the Deutsches Museum in München, Germany. Massolle and Vogt secured patents from 1919 in Germany, applied for a US patent on 20 March 1922; the first public showing of Tri-Ergon sound films took place in the Alhambra at 68 Kurfürstendamm, Berlin on 17 September 1922. The inventors sold their patent to Swiss financial backers who formed Tri-Ergon AG in Zürich, Switzerland to continue developing their process. In 1924 Universum-Film AG produced three hours' worth of vaudeville shorts with sound, similar to those produced by Warner Brothers, who used a sound-on-disc system. Tri-Ergon AG licensed the recording film rights to Ufa in January 1925 and Masolle became technical director of Ufa's first sound-film division. However, the non-standard film format was not popular: a well-publicized tour of Germany in 1925 failed to generate much interest.
Ufa's first sound film, the 20-minute short Das Mädchen mit den Schwefelhölzern was directed by Guido Bagier. Bagier wrote the music for the film, it premièred at the Mozartsaal in December 1925, but was a total flop in terms of technical sound quality. According to Bagier, the fiasco was due to technical problems with the playback equipment. In the meantime, having ducked the whole issue of sound films, had still fallen into severe financial difficulties with productions of vastly expensive silent films accompanied by a live symphony orchestra playing a specially-composed score, such as F. W. Murnau's Der Letzte Mann, with Emil Jannings and Faust. Paramount Pictures and Metro-Goldwyn-Mayer stepped into the financial breach with the restrictive Parufamet agreement of December 1925, whereby the American firms took control of all Ufa's first-run theatres to show American films. Only one significant German film was shown in Ufa first-run cinemas in Berlin during this whole time the agreement was in effect: Joe May's silent The Farmer from Texas.
The Fox Film Corporation was an American company that produced motion pictures, formed by William Fox on 1 February 1915. It was the corporate successor to his earlier Greater New York Film Rental Company and Box Office Attractions Film Company; the company's first film studios were set up in Fort Lee, New Jersey but in 1917, William Fox sent Sol M. Wurtzel to Hollywood, California to oversee the studio's new West Coast production facilities where a more hospitable and cost effective climate existed for filmmaking. On July 23, 1926, the company bought the patents of the Movietone sound system for recording sound on to film. After the Crash of 1929, William Fox lost control of the company during a hostile takeover. Under new president Sidney Kent, the new owners merged the company with Twentieth Century Pictures to form 20th Century Fox in 1935. William Fox entered the film industry in 1904 when he purchased a one-third share of a Brooklyn nickelodeon for $1,667, he reinvested his profits from that initial location, expanding to fifteen similar venues in the city, purchasing prints from the major studios of the time: Biograph, Kalem, Pathé, Vitagraph.
After experiencing further success presenting live vaudeville routines along with motion pictures, he expanded into larger venues beginning with his purchase of the disused Gaiety theater, continuing with acquisitions throughout New York City and New Jersey, including the Academy of Music. Fox invested further in the film industry by founding the Greater New York Film Rental Company as a film distributor. However, the major film studios formed the Motion Picture Patents Company in 1908 and the General Film Company in 1910, in an effort to create a monopoly on the creation and distribution of motion pictures. Fox refused to sell out to the monopoly, sued under the Sherman Antitrust Act receiving a $370,000 settlement, ending restrictions on the length of films and the prices that could be paid for screenplays. In 1914, reflecting the broader scope of his business, he renamed it the Box Office Attraction Film Rental Company, he entered into a contract with the Balboa Amusement Producing Company film studio, purchasing all of their films for showing in his New York area theaters and renting the prints to other exhibitors nationwide.
He continued to distribute material from other sources, such as Winsor McCay's early animated film Gertie the Dinosaur. That year, Fox concluded that depending on other companies for the products he depended on was insufficient, he purchased the Éclair studio facilities in Fort Lee, New Jersey, along with property in Staten Island, arranged for actors and crew. The company became a film studio, with its name shortened to the Box Office Attractions Company. Always more of an entrepreneur than a showman, Fox concentrated on building theaters; the company's first film studios were set up in Fort Lee, New Jersey where it and many other early film studios in America's first motion picture industry were based at the beginning of the 20th century. In 1914, Fox Film began making motion pictures in California, in 1915 decided to build its own permanent studio; the company leased the Edendale studio of the Selig Polyscope Company until its own studio, located at Western Avenue and Sunset Boulevard, was completed in 1916.
In 1917, William Fox sent Sol M. Wurtzel to Hollywood to oversee the studio's West Coast production facilities where a more hospitable and cost-effective climate existed for filmmaking. With the introduction of sound technology, Fox moved to acquire the rights to a sound-on-film process. In the years 1925–26, Fox purchased the rights to the work of Freeman Harrison Owens, the U. S. rights to the Tri-Ergon system invented by three German inventors, the work of Theodore Case. This resulted in the Movietone sound system known as "Fox Movietone" developed at the Movietone Studio; that year, the company began offering films with a music-and-effects track, the following year Fox began the weekly Fox Movietone News feature, that ran until 1963. The growing company needed space, in 1926 Fox acquired 300 acres in the open country west of Beverly Hills and built "Movietone City", the best-equipped studio of its time; when rival Marcus Loew died in 1927, Fox offered to buy the Loew family's holdings. Loew's Inc. controlled more than 200 theaters, as well as the MGM studio.
When the family agreed to the sale, the merger of Fox and Loew's Inc. was announced in 1929. But MGM studio boss Louis B. Mayer was not fought back. Using political connections, Mayer called on the Justice Department's antitrust unit to delay giving final approval to the merger. Fox was badly injured in a car crash in the summer of 1929, by the time he recovered he had lost most of his fortune in the fall 1929 stock market crash, ending any chance of the merger going through without the Justice Department's objections. Overextended and close to bankruptcy, Fox was stripped of his empire in 1930 and ended up in jail for bribery charges. Fox Film, with more than 500 theatres, was placed in receivership. A bank-mandated reorganization propped the company up for a time, but it soon became apparent that despite its size, Fox could not stand on its own. William Fox resented the way he was forced out of the company and portrayed it as an active conspiracy against him in the 1933 book Upton Sinclair Presents William Fox.
Under new president Sidney Kent, the new owners began negotiating with the upstart, but powerful independent Twentieth Century Pictures in the early spring of 1935. The two companies merged that spring as 20th Century-Fox. For many years, 20th Century Fox claimed to hav
Magnetism is a class of physical phenomena that are mediated by magnetic fields. Electric currents and the magnetic moments of elementary particles give rise to a magnetic field, which acts on other currents and magnetic moments; the most familiar effects occur in ferromagnetic materials, which are attracted by magnetic fields and can be magnetized to become permanent magnets, producing magnetic fields themselves. Only a few substances are ferromagnetic; the prefix ferro- refers to iron, because permanent magnetism was first observed in lodestone, a form of natural iron ore called magnetite, Fe3O4. Although ferromagnetism is responsible for most of the effects of magnetism encountered in everyday life, all other materials are influenced to some extent by a magnetic field, by several other types of magnetism. Paramagnetic substances such as aluminum and oxygen are weakly attracted to an applied magnetic field; the force of a magnet on paramagnetic and antiferromagnetic materials is too weak to be felt, can be detected only by laboratory instruments, so in everyday life these substances are described as non-magnetic.
The magnetic state of a material depends on temperature and other variables such as pressure and the applied magnetic field. A material may exhibit more than one form of magnetism as these variables change; as with magnetising a magnet, demagnetising a magnet is possible. "Passing an alternate current, or hitting a heated magnet in an east west direction are ways of demagnetising a magnet", quotes Sreekethav. Magnetism was first discovered in the ancient world, when people noticed that lodestones magnetized pieces of the mineral magnetite, could attract iron; the word magnet comes from the Greek term μαγνῆτις λίθος magnētis lithos, "the Magnesian stone, lodestone." In ancient Greece, Aristotle attributed the first of what could be called a scientific discussion of magnetism to the philosopher Thales of Miletus, who lived from about 625 BC to about 545 BC. The ancient Indian medical text Sushruta Samhita describes using magnetite to remove arrows embedded in a person's body. In ancient China, the earliest literary reference to magnetism lies in a 4th-century BC book named after its author, The Sage of Ghost Valley.
The 2nd-century BC annals, Lüshi Chunqiu notes: "The lodestone makes iron approach, or it attracts it." The earliest mention of the attraction of a needle is in a 1st-century work Lunheng: "A lodestone attracts a needle." The 11th-century Chinese scientist Shen Kuo was the first person to write—in the Dream Pool Essays—of the magnetic needle compass and that it improved the accuracy of navigation by employing the astronomical concept of true north. By the 12th century the Chinese were known to use the lodestone compass for navigation, they sculpted a directional spoon from lodestone in such a way that the handle of the spoon always pointed south. Alexander Neckam, by 1187, was the first in Europe to describe the compass and its use for navigation. In 1269, Peter Peregrinus de Maricourt wrote the Epistola de magnete, the first extant treatise describing the properties of magnets. In 1282, the properties of magnets and the dry compasses were discussed by Al-Ashraf, a Yemeni physicist and geographer.
In 1600, William Gilbert published his De Magnete, Magneticisque Corporibus, et de Magno Magnete Tellure. In this work he describes many of his experiments with his model earth called the terrella. From his experiments, he concluded that the Earth was itself magnetic and that this was the reason compasses pointed north. An understanding of the relationship between electricity and magnetism began in 1819 with work by Hans Christian Ørsted, a professor at the University of Copenhagen, who discovered by the accidental twitching of a compass needle near a wire that an electric current could create a magnetic field; this landmark experiment is known as Ørsted's Experiment. Several other experiments followed, with André-Marie Ampère, who in 1820 discovered that the magnetic field circulating in a closed-path was related to the current flowing through the perimeter of the path. James Clerk Maxwell synthesized and expanded these insights into Maxwell's equations, unifying electricity and optics into the field of electromagnetism.
In 1905, Einstein used these laws in motivating his theory of special relativity, requiring that the laws held true in all inertial reference frames. Electromagnetism has continued to develop into the 21st century, being incorporated into the more fundamental theories of gauge theory, quantum electrodynamics, electroweak theory, the standard model. Magnetism, at its root, arises from two sources: Electric current. Spin magnetic moments of elementary particles; the magnetic properties of materials are due to the magnetic moments of their atoms' orbiting electrons. The magnetic moments of the nuclei of atoms are thousands of times smaller than the electro
Phonofilm is an optical sound-on-film system developed by inventors Lee de Forest and Theodore Case in the 1920s. In 1919 and 1920, Lee De Forest, inventor of the audion tube, filed his first patents on a sound-on-film process, DeForest Phonofilm, which recorded sound directly onto film as parallel lines; these parallel lines photographically recorded electrical waveforms from a microphone, which were translated back into sound waves when the movie was projected. Some sources say that DeForest improved on the work of Finnish inventor Eric Tigerstedt —, granted German patent 309.536 on 28 July 1914 for his sound-on-film work — and on the Tri-Ergon process, patented in 1919 by German inventors Josef Engl, Hans Vogt, Joseph Massole. The Phonofilm system, which recorded synchronized sound directly onto film, was used to record vaudeville acts, musical numbers, political speeches, opera singers; the quality of Phonofilm was poor at first, improved somewhat in years, but was never able to match the fidelity of sound-on-disc systems such as Vitaphone, or sound-on-film systems such as RCA Photophone or Fox Movietone.
The films of DeForest were short films made as demonstrations to try to interest major studios in Phonofilm. These films are valuable to entertainment historians, as they include recordings of a wide variety of both well-known and less famous American vaudeville and British music hall acts which would otherwise have been forgotten; some of the films, such as Flying Jenny Airplane, Barking Dog, a film of DeForest himself explaining the Phonofilm system were experimental films to test the system. Some of the people filmed included vaudevillians Joe Weber and Lew Fields, Eva Puck and Sammy White, Eddie Cantor, Ben Bernie, Oscar Levant, Phil Baker, Frank McHugh, Roy Smeck, jazz musicians Noble Sissle and Eubie Blake, "all-girl" bandleader Helen Lewis, harmonicist Borrah Minevitch, Nikita Balieff's company La Chauve-Souris, opera singers Eva Leoni, Abbie Mitchell, Marie Rappold, Broadway stars Helen Menken and Fannie Ward, folklorist Charles Ross Taggart, copla singer Concha Piquer, politicians Calvin Coolidge, Robert La Follette, Al Smith, Franklin D. Roosevelt.
Smith and Roosevelt were filmed during the 1924 Democratic National Convention, held June 24 to July 9 at Madison Square Garden in New York City. Coolidge became the first U. S. President to appear in a sound motion picture when DeForest filmed him at the White House on 11 August 1924. In November 1922, De Forest founded the De Forest Phonofilm Corporation with studios at 314 East 48th Street in New York City, offices at 220 West 42nd Street in the Candler Building. However, DeForest was unable to interest any of the major Hollywood movie studios in his invention. From October 1921 to September 1922, DeForest lived in Berlin, meeting with the Tri-Ergon developers and investigating other European sound film systems, he announced to the press in April 1922. On 12 March 1923, DeForest presented a demonstration of Phonofilm to the press. On 12 April 1923, DeForest gave a private demonstration of the process to electrical engineers at the Engineering Society Building's Auditorium at 33 West 39th Street in New York City.
On 15 April 1923, DeForest premiered 18 short films made in Phonofilm — including vaudeville acts, musical performers and ballet — at the Rivoli Theater at 1620 Broadway in New York City. The Rivoli's music director Hugo Riesenfeld co-hosted the presentation; the printed program gave credit to the "DeForest-Case Patents", but according to a letter Theodore Case wrote to DeForest after the event, no credit was given to Case during the presentation itself. Case expressed his displeasure that the program credited only the "DeForest-Case Patents", as Phonofilm's success was due to the work of Case and his Case Research Lab. DeForest took his show on the road, pitching Phonofilm directly to the general public at a series of special engagements across the country; the shorts shown at one such demonstration, exact date unknown but circa 1925, were as follows: What the Phonofilm Means A Study in Contrasts From Far Seville Old Melodies The Harlequin's Serenade Stringed Harmony Parade of the Wooden Soldiers A Few Moments With Eddie Cantor, Star of "Kid Boots" A Musical Monologue President Calvin Coolidge Taken on the White House Lawn Ben Bernie's Orchestra Rigoletto, Act Two The Bubble Dance Weber and Fields A Boston Star DeWolfe Hopper Negro Folk Songs Opera Versus Jazz DeForest was forced to show these films in independent theaters such as the Rivoli, since Hollywood movie studios controlled all major U.
S. movie theater chains at the time. De Forest's decision to film short films, not feature films limited the appeal of his process. All or part of the Paramount Pictures features Bella Donna and The Covered Wagon were filmed with Phonofilm as an experiment. However, the Phonofilm versions were only shown at the premiere engagements at
A release print is a copy of a film, provided to a movie theater for exhibition. Release prints are not to be confused with other types of print used in the photochemical post-production process: Rush prints are one-light, contact-printed copies made from an unedited roll of original camera negative after processing and screened to the cast and crew in order to ensure that the takes can be used in the final film. Workprints, sometimes called cutting copies, like rush prints, copies of a camera negative roll, they are used for editing before the negative itself is conformed, or cut to match the edited workprint. An answer print is made either from the cut camera negative or an interpositive, depending on the production workflow, in order to verify that the grading conforms to specifications, so that final adjustments can be made before the main batch of release prints is made. A Showprint is a high quality projection print made for screening at special events such as gala premieres, it is printed directly from the composited camera negative, with each shot individually timed as a duplicate intermediate element would be, onto a higher quality of print stock than is usual for mass-production release prints.
As a showprint is at least two generations closer to the composited camera negative than a typical release print, the definition and saturation in the projected image is higher. Showprints have been colloquially referred to as "EKs", since "Showprint" is a tradename of DeLuxe, although it is not a registered trademark. In the traditional photochemical post-production workflow, release prints are copies, made using a high-speed continuous contact printer, of an internegative, which in turn is a copy of an interpositive, which in turn is a copy, optically printed to incorporate special effects, etc. from the cut camera negative. In short, a typical release print is three generations removed from the cut camera negative; the post-production of many feature films is now carried out using a digital intermediate workflow, in which the uncut camera negative is scanned and other post-production functions are carried out using computers, an internegative is burnt out to film, from which the release prints are struck in the normal way.
This procedure eliminates at least one generation of analogue duplication and results in a higher quality of release prints. It has the further advantage that a Digital Cinema Package can be produced as the final output in addition to or instead of film prints, meaning that a single post-production workflow can produce all the required distribution media; as of March 2015, Eastman Kodak is the only remaining manufacturer of colour release print stock in the world. Along with Kodak, ORWO of Germany sells black-and-white print stock. Other manufacturers, principally DuPont of the United States, Fujifilm of Japan, Agfa-Gevaert of Germany, Ilford of the United Kingdom and Tasma of the Soviet Union competed with Kodak in the print stock market throughout most of the twentieth century; the person operating the printer on which the release print is struck must take several factors into consideration in order to achieve accurate color. These include the stock manufacturer, the color temperature of the bulbs in the printer, the various color filters which may have been introduced during initial filming or subsequent generation of duplicates.
At the theater, release prints are projected through an aperture plate, placed between the film and the projector's light source. The aperture plate in combination with a prime lens of the appropriate focal distance determines which areas of the frame are magnified and projected and which are masked out, according to the aspect ratio in which the film is intended to be projected. Sometimes a hard matte is used in printing to ensure that only the area of the frame shot in the camera, intended to be projected is present on the release print; some theaters have used aperture plates that mask away part of the frame area, supposed to be projected where the screen is too small to accommodate a wider ratio and does not have a masking system in front of the screen itself. The audience may be confused. Director Brad Bird expressed frustration at this practice, which some theaters applied to his film The Incredibles. Release prints are expensive. For example, in the United States, it is not unusual for each one to cost around $1,500 to print and ship to theaters around the country.
The cost of a release print is determined by its length, the type of print stock used and the number of prints being struck in a given run. Laser subtitling release prints of foreign language films adds to the cost per print. Due to the fear of piracy, distributors try to ensure that prints are returned and destroyed after the movie's theatrical run is complete. However, small numbers of release prints do end up in the hands of private collectors entering this market via projectionists, who retain their prints at the end of the run and do not return them. A significant number of films have been preserved this way, via prints being donated to film archives and preservation masters printed from them; the polyester film base is recycled. EKs are more expensive as they are completely made by hand and to much higher quality standards
Fantasia (1940 film)
Fantasia is a 1940 American animated film produced by Walt Disney and released by Walt Disney Productions. With story direction by Joe Grant and Dick Huemer, production supervision by Ben Sharpsteen, it is the third Disney animated feature film; the film consists of eight animated segments set to pieces of classical music conducted by Leopold Stokowski, seven of which are performed by the Philadelphia Orchestra. Music critic and composer Deems Taylor acts as the film's Master of Ceremonies, providing a live-action introduction to each animated segment. Disney settled on the film's concept as work neared completion on The Sorcerer's Apprentice, an elaborate Silly Symphonies short designed as a comeback role for Mickey Mouse, who had declined in popularity; as production costs grew higher than what it could earn, Disney decided to include the short in a feature-length film with other segments set to classical pieces. The soundtrack was recorded using multiple audio channels and reproduced with Fantasound, a pioneering sound reproduction system that made Fantasia the first commercial film shown in stereophonic sound.
Fantasia was first released as a theatrical roadshow held in thirteen U. S. cities from November 13, 1940. While acclaimed by critics, it was unable to make a profit due to World War II cutting off distribution to the European market, the film's high production costs, the expense of leasing theatres and installing the Fantasound equipment for the roadshow presentations; the film was subsequently reissued multiple times with its original footage and audio being deleted, modified, or restored in each version. Fantasia is the 23rd highest-grossing film of all time in the U. S. when adjusted for inflation. The Fantasia franchise has grown to include video games, Disneyland attractions, a live concert. A sequel, Fantasia 2000, co-produced by Roy E. Disney, was released in 1999. Fantasia has grown in reputation over the years and is now acclaimed. Fantasia opens with live action scenes of members of an orchestra gathering against a blue background and tuning their instruments in half-light, half-shadow.
Master of ceremonies Deems Taylor introduces the program. Toccata and Fugue in D Minor by Johann Sebastian Bach. Live-action shots of the orchestra illuminated in blue and gold, backed by superimposed shadows, fade into abstract patterns. Animated lines and cloud formations reflect the sound and rhythms of the music. Nutcracker Suite by Pyotr Ilyich Tchaikovsky. Selections from the ballet suite underscore scenes depicting the changing of the seasons from summer to autumn to winter. A variety of dances are presented with fairies, flowers and leaves, including "Dance of the Sugar Plum Fairy", "Chinese Dance", "Arabian Dance", "Russian Dance", "Dance of the Flutes" and "Waltz of the Flowers"; the Sorcerer's Apprentice by Paul Dukas. Based on Goethe's 1797 poem "Der Zauberlehrling". Mickey Mouse, the young apprentice of the sorcerer Yen Sid, attempts some of his master's magic tricks but does not know how to control them. Rite of Spring by Igor Stravinsky. A visual history of the Earth's beginnings is depicted to selected sections of the ballet score.
The sequence progresses from the planet's formation to the first living creatures, followed by the reign and extinction of the dinosaurs. Intermission/Meet the Soundtrack: The orchestra musicians depart and the Fantasia title card is revealed. After the intermission there is a brief jam session of jazz music led by a clarinettist as the orchestra members return. A humorously stylized demonstration of how sound is rendered on film is shown. An animated sound track "character" a straight white line, changes into different shapes and colors based on the sounds played; the Pastoral Symphony by Ludwig van Beethoven. A mythical Greco-Roman world of colorful centaurs and "centaurettes", cupids and other figures from classical mythology is portrayed to Beethoven's music. A gathering for a festival to honor Bacchus, the god of wine, is interrupted by Zeus, who creates a storm and directs Vulcan to forge lightning bolts for him to throw at the attendees. Dance of the Hours by Amilcare Ponchielli. A comic ballet in four sections: Madame Upanova and her ostriches.
The finale finds all of the characters dancing together until their palace collapses. Night on Bald Mountain by Modest Mussorgsky and Ave Maria by Franz Schubert. At midnight the devil Chernabog awakes and summons evil spirits and restless souls from their graves to Bald Mountain; the spirits dance and fly through the air until driven back by the sound of an Angelus bell as night fades into dawn. A chorus is heard singing Ave Maria as a line of robed monks is depicted walking with lighted torches through a forest and into the ruins of a cathedral. In 1936, Walt Disney felt that the Disney studio's star character Mickey Mouse needed a boost in popularity, he decided to feature the mouse in The Sorcerer's Apprentice, a deluxe cartoon short based on the poem written by Johann Wolfgang von Goethe and set to the orchestral piece by Paul Dukas inspired by the original tale. The concept of matching animation to classical music was used as early as 1928 in Disney's cartoon series, the Silly Symphonies, but he wanted to go beyond the usual slapstick, produce shorts where "sheer fantasy unfolds... action controlled by a musical pattern has great charm in the realm of unreality."
Upon receiving the rights to use the music by the end of Ju
A light-emitting diode is a semiconductor light source that emits light when current flows through it. Electrons in the semiconductor recombine with electron holes, releasing energy in the form of photons; this effect is called electroluminescence. The color of the light is determined by the energy required for electrons to cross the band gap of the semiconductor. White light is obtained by using multiple semiconductors or a layer of light-emitting phosphor on the semiconductor device. Appearing as practical electronic components in 1962, the earliest LEDs emitted low-intensity infrared light. Infrared LEDs are used in remote-control circuits, such as those used with a wide variety of consumer electronics; the first visible-light LEDs were of low intensity and limited to red. Modern LEDs are available across the visible and infrared wavelengths, with high light output. Early LEDs were used as indicator lamps, replacing small incandescent bulbs, in seven-segment displays. Recent developments have produced white-light LEDs suitable for room lighting.
LEDs have led to new displays and sensors, while their high switching rates are useful in advanced communications technology. LEDs have many advantages over incandescent light sources, including lower energy consumption, longer lifetime, improved physical robustness, smaller size, faster switching. Light-emitting diodes are used in applications as diverse as aviation lighting, automotive headlamps, general lighting, traffic signals, camera flashes, lighted wallpaper and medical devices. Unlike a laser, the color of light emitted from an LED is neither coherent nor monochromatic, but the spectrum is narrow with respect to human vision, functionally monochromatic. Electroluminescence as a phenomenon was discovered in 1907 by the British experimenter H. J. Round of Marconi Labs, using a crystal of silicon carbide and a cat's-whisker detector. Russian inventor Oleg Losev reported creation of the first LED in 1927, his research was distributed in Soviet and British scientific journals, but no practical use was made of the discovery for several decades.
In 1936, Georges Destriau observed that electroluminescence could be produced when zinc sulphide powder is suspended in an insulator and an alternating electrical field is applied to it. In his publications, Destriau referred to luminescence as Losev-Light. Destriau worked in the laboratories of Madame Marie Curie an early pioneer in the field of luminescence with research on radium. Hungarian Zoltán Bay together with György Szigeti pre-empted led lighting in Hungary in 1939 by patented a lighting device based on SiC, with an option on boron carbide, that emmitted white, yellowish white, or greenish white depending on impurities present. Kurt Lehovec, Carl Accardo, Edward Jamgochian explained these first light-emitting diodes in 1951 using an apparatus employing SiC crystals with a current source of battery or pulse generator and with a comparison to a variant, crystal in 1953. Rubin Braunstein of the Radio Corporation of America reported on infrared emission from gallium arsenide and other semiconductor alloys in 1955.
Braunstein observed infrared emission generated by simple diode structures using gallium antimonide, GaAs, indium phosphide, silicon-germanium alloys at room temperature and at 77 kelvins. In 1957, Braunstein further demonstrated that the rudimentary devices could be used for non-radio communication across a short distance; as noted by Kroemer Braunstein "…had set up a simple optical communications link: Music emerging from a record player was used via suitable electronics to modulate the forward current of a GaAs diode. The emitted light was detected by a PbS diode some distance away; this signal was played back by a loudspeaker. Intercepting the beam stopped the music. We had a great deal of fun playing with this setup." This setup presaged the use of LEDs for optical communication applications. In September 1961, while working at Texas Instruments in Dallas, James R. Biard and Gary Pittman discovered near-infrared light emission from a tunnel diode they had constructed on a GaAs substrate. By October 1961, they had demonstrated efficient light emission and signal coupling between a GaAs p-n junction light emitter and an electrically isolated semiconductor photodetector.
On August 8, 1962, Biard and Pittman filed a patent titled "Semiconductor Radiant Diode" based on their findings, which described a zinc-diffused p–n junction LED with a spaced cathode contact to allow for efficient emission of infrared light under forward bias. After establishing the priority of their work based on engineering notebooks predating submissions from G. E. Labs, RCA Research Labs, IBM Research Labs, Bell Labs, Lincoln Lab at MIT, the U. S. patent office issued the two inventors the patent for the GaAs infrared light-emitting diode, the first practical LED. After filing the patent, Texas Instruments began a project to manufacture infrared diodes. In October 1962, TI announced the first commercial LED product, which employed a pure GaAs crystal to emit an 890 nm light output. In October 1963, TI announced the first commercial hemispherical LED, the SNX-110; the first visible-spectrum LED was developed in 1962 by Nick Holonyak, Jr. while working at General Electric. Holonyak first reported his LED in the journal Applied Physics Letters on December 1, 1962.
M. George Craford, a former graduate student of Holonyak, invented the first yellow LED and improved the brightness of red and red-orange LEDs by a factor of ten in 1972. In 1976, T. P. Pearsall created the first high-brightness, high-efficiency LEDs for optical fiber telecommunicat