Gobo is a sound recording term for a movable acoustic isolation panel. In typical use, a recording engineer might put a gobo between two musicians to increase the isolation of their microphones from each other. For the stage and photographic lighting use of gobo, see Gobo; the origin of the term "gobo" is obscure, but is most short for "go-between." The gobo was invented by Charles Norris Hoyle, was a product of TayTrix. Gobo panels control the acoustical properties of a room by diffusing sound waves. Uses include treating recording and mixing areas for unwanted reverberation, or to separate two or more musicians so they can play close to each other with separate microphones. Gobo panels are constructed to accommodate portability and storage, an advantage over more permanent acoustical room treatments. A gobo consists of a wooden panel covered with foam, carpeting or other materials with sound damping properties. A gobo can be raised on adjustable legs. Clearsonic Forward Acoustics Primacousics Taytrix Yukon Acoustics World Wide Words – Michael Quinion writes about international English from a British viewpoint.
Ellipsoidal reflector spotlight
Ellipsoidal reflector light is the name for a type of stage lighting instrument, named for the ellipsoidal reflector used to collect and direct the light through a barrel that contains a lens or lens train. The optics of an ERS instrument are similar to those of a 35 mm slide projector. There are many types of ERS that are designed for the myriad applications found in the entertainment industry. ERS instruments come in all sizes; each particular model of ERS has its own set of characteristics. ERS instruments are the most varied and utilized type of stage lighting instrument. ERS may be referred to as Profile Spotlights because the beam can be shaped to the profile of an object. Ellipsoidal reflectors are used for their versatility. Leko and Source Four are brand names which are but inaccurately, used to refer to any sort of ellipsoidal. Characteristics of a typical ellipsoidal lighting unit include: An ellipsoidal reflector An adjustable lens tube containing the lens or lens train. Adjusting the tube by pushing it further in or pulling it further out of the unit allows changes to the focus of the beam of light projected by the unit.
This results from changing the distance between the lens train. "Zoom" ERS instruments can vary the size of beam as well as the focus One or two Plano-Convex lenses within the lens tube to create the lens train. The Plano-Convex lenses, named for having one flat side and one convex side, have their convex sides facing each other within the tube; the distance between these lenses and the distance between them and the reflector determines how wide the output beam of light is A set of brackets on the end of the lens tube for the insertion of gel frames, a color changing unit or any variety of accessories. Most modern units include two slots that allow for combining different accessories A series of four shutters mounted at the internal focal point of the unit; these allow for precise sizing of the unit's beam as lines. Additionally, an iris may be present to size the beam circularly. A slot in the body of the unit for the insertion of metal gobos to change the pattern of the light in most cases is present, this slot can hold a glass gobo, dichroic colour roundel or an effects unit such as a gobo rotator or irisThe lamps are loaded from the rear, either mounted axially, or radially with the base either up or down at a 45-degree angle or sometimes at a 90-degree angle.
The filament of the lamp is at one focal point of the ellipsoidal reflector and the gate with the shutters and gobo are at the other focal point. Ellipsoidals are supplied with a certain size lens or lenses that determines the field angle, anywhere from five to ninety degrees. Field angle is the angle of the beam of light where it reaches 10% of the intensity of the center of the beam. Most manufacturers now use field angle to indicate the fixture's spread in this series. Older fixtures are described by the width of the lens x focal length of the instrument. For example, a 6x9 ellipsoidal would have a 6" diameter lens and a focal length of 9". 6x9 Instruments have a field angle of 37°. 6x12 instruments have a field angle of 27°. As the field angle narrows, the instrument can be used further from the stage. Variable focus instruments with two lenses that move in and out from the lamp housing are available, allowing the user to manually adjust to the desired focal length within a certain range. Ellipsoidals can be used for any job but their primary function is to illuminate a specific proximity.
They are the common use for spotlights. It has an ellipsoidal reflector behind the lamp to reflect the light in the direction required, they have brackets on the end to attach gels and barn doors. Barn doors give a softer edge; the Electronic Theatre Controls Source Four, released in 1992, updated the traditional ERS design. The company took advantage of advances in lamp and reflector technology to increase luminous output with less wattage; the Source Four name comes from the improved lamp design utilizing four filament elements. Other improvements included the use of a single lens in most lens trains, making the unit lighter and more efficient in regards to light output, a rotating barrel containing lens tube assembly and accessory slot to allow increased precision in use of the shutters and/or more registering gobos. Since the release of the Source Four, other lighting manufacturers have since revised their products to compete in the market share alongside the ETC; the Selecon Pacific, an L shaped ERS, has an irregular shape due to an integrated dichroic cold mirror, which splits the visible wavelengths of the light beam from the infrared, allowing the heat to be drawn off by a heat sink and away from the instrument.
This keeps the beam of the fixture cool allowing for the use of plastic gobos. The beam improves shutter and color gel life, can improve the temperature on stage. Altman Lighting released their Shakespeare line of units in 1994 as a response to the Source Four. One improvement over the Source Four is a wider range of adjustment in regards to rotation of the barrel assembly; the patents for some components in this unit have been licensed from ETC. In 2004 ADB introduced WARP Profile - In this ellipsoidal profile spot convention
The term stained glass can refer to coloured glass as a material or to works created from it. Throughout its thousand-year history, the term has been applied exclusively to the windows of churches and other significant religious buildings. Although traditionally made in flat panels and used as windows, the creations of modern stained glass artists include three-dimensional structures and sculpture. Modern vernacular usage has extended the term "stained glass" to include domestic lead light and objects d'art created from foil glasswork exemplified in the famous lamps of Louis Comfort Tiffany; as a material stained glass is glass, coloured by adding metallic salts during its manufacture. The coloured glass is crafted into stained glass windows in which small pieces of glass are arranged to form patterns or pictures, held together by strips of lead and supported by a rigid frame. Painted details and yellow stain are used to enhance the design; the term stained glass is applied to windows in which the colours have been painted onto the glass and fused to the glass in a kiln.
Stained glass, as an art and a craft, requires the artistic skill to conceive an appropriate and workable design, the engineering skills to assemble the piece. A window must fit snugly into the space for which it is made, must resist wind and rain, especially in the larger windows, must support its own weight. Many large windows have withstood the test of time and remained intact since the Late Middle Ages. In Western Europe they constitute the major form of pictorial art to have survived. In this context, the purpose of a stained glass window is not to allow those within a building to see the world outside or primarily to admit light but rather to control it. For this reason stained glass windows have been described as "illuminated wall decorations"; the design of a window may be figurative. Windows within a building may be thematic, for example: within a church – episodes from the life of Christ. Stained glass is still popular today, but referred to as art glass, it is prevalent in luxury homes, commercial buildings, places of worship.
Artists and companies are contracted to create beautiful art glass ranging from domes, backsplashes, etc. During the late medieval period, glass factories were set up where there was a ready supply of silica, the essential material for glass manufacture. Silica requires a high temperature to melt, something not all glass factories were able to achieve; such materials as potash and lead can be added to lower the melting temperature. Other substances, such as lime, are added to rebuild the weakened network and make the glass more stable. Glass is coloured by adding metallic oxide powders or finely divided metals while it is in a molten state. Copper oxides produce green or bluish green, cobalt makes deep blue, gold produces wine red and violet glass. Much modern red glass is produced using copper, less expensive than gold and gives a brighter, more vermilion shade of red. Glass coloured while in the clay pot in the furnace is known as pot metal glass, as opposed to flashed glass. Using a blow-pipe, a "gather" of molten glass is taken from the pot heating in the furnace.
The gather is formed to a bubble of air blown into it. Using metal tools, molds of wood that have been soaking in water, gravity, the gather is manipulated to form a long, cylindrical shape; as it cools, it is reheated. During the process, the bottom of the cylinder is removed. Once brought to the desired size it is left to cool. One side of the cylinder is opened, it is put into another oven to heat and flatten it, placed in an annealer to cool at a controlled rate, making the material more stable. "Hand-blown" cylinder and crown glass were the types used in ancient stained-glass windows. Stained glass windows were in churches and chapels as well as many more well respected buildings; this hand-blown glass is created by blowing a bubble of air into a gather of molten glass and spinning it, either by hand or on a table that revolves like a potter's wheel. The centrifugal force causes the molten bubble to flatten, it can be cut into small sheets. Glass formed this way can be either coloured and used for stained-glass windows, or uncoloured as seen in small paned windows in 16th- and 17th-century houses.
Concentric, curving waves are characteristic of the process. The center of each piece of glass, known as the "bull's-eye", is subject to less acceleration during spinning, so it remains thicker than the rest of the sheet, it has the distinctive lump of glass left by the "pontil" rod, which holds the glass as it is spun out. This lumpy, refractive quality means the bulls-eyes are less transparent, but they have still been used for windows, both domestic and ecclesiastical. Crown glass is still made today, but not on a large scale. Rolled glass is produced by pouring molten glass onto a metal or graphite table and rolling it into a sheet using a large metal cylinder, similar to rolling out a pie crust; the rolling can be done by machine. Glass can be "double rolled", which means it is passed through two cylinders at once to yield glass of a specified thickness (typically about 1/8" or
Intelligent lighting refers to stage lighting that has automated or mechanical abilities beyond those of traditional, stationary illumination. Although the most advanced intelligent lights can produce extraordinarily complex effects, the intelligence lies with the designer of the control system rather than the programmer of the show or the lighting operator. For this reason, intelligent lighting is known as automated lighting, moving lights or moving heads. There are many patents for intelligent lighting dating back from 1906, with Edmond Sohlberg of Kansas City, USA; the lantern used a carbon-arc bulb and was operated not by motors or any form of electronics, but by cords that were operated manually to control pan and zoom. 1925 saw the first use of electrical motors to move the fixture, with it the beam position, by Herbet F. King. In 1936 US patent number 2,054,224 was granted to a similar device, with which the pan and tilt were controlled by means of a joystick as opposed to switches. From this point on until 1969, various other inventors made similar lights and improved on the technology, but with no major breakthroughs.
During this period, Century Lighting started retailing such units specially made to order, retrofitted onto any of their existing lanterns up to 750 W to control pan and tilt. George Izenour made the next breakthrough in 1969 with the first fixture to use a mirror on the end of an ellipsoidal to redirect the beam of light remotely. In 1969, Jules Fisher, from Casa Mañana area theatre in Texas saw the invention and use of 12 PAR 64 lanterns with 120 W, 12 V lamps fitted, 360 degrees of pan and 270 degrees of tilt, a standard that lasted until the 1990s; this lamp was known as the'Mac-Spot' In Bristol in 1968, progress was being made for use in live music. Peter Wynne Wilson refers to the use of 1 kW profiles, with slides onto which gobos were printed, inserted from a reel just like on a slide projector; the fixtures had an iris, a multiple coloured gel wheel. These lights were fitted with mirrors and made for an impressive light show for a Pink Floyd Gig in London. Another fixture known as the'Cycklops' was used for music in the USA, although it was limited in terms of capabilities.
With only pan and color functions, at 1.2 meters long and weighing in at 97 kilograms including the ballast, they were heavy and cumbersome. These units were designed more for replacing the unreliable local spotlight operators. In 1978 a Dallas, Texas-based lighting and sound company called Showco began developing a lighting fixture that changed color by rotating dichroic filters. During its development, the designers decided to add motors to motorize pan and tilt, they demonstrated the fixture for the band Genesis in a barn in England in 1980. The band decided to financially back the project. Showco spun off their lighting project into a company called Vari-Lite, the first fixture was called the Vari-lite, it used one of the first lighting desks with a digital core and this enabled lighting states to be programmed in. Genesis was to order 55 Vari-lites to use in their next chain of gigs across the UK; the lights were supplied with a Vari-Lite console which had 32 channels, five 1802 processors and a dramatic improvement of the first console, simple and had an external processing unit.
In 1986 Vari-Lite introduced a new series of lighting fixtures and control consoles. They referred to the new system as their Series 200, with the new lights designated "VL-2 Spot Luminaire", "VL-3 Wash Luminaire"; the Series 200 system was controlled by the Artisan console. Vari-Lite retroactively named the original system "series-100"; the Original Vari-Lite console was retroactively named the "series 100 console" and the original Vari-Lite was retroactively named the "VL-1 Spot Luminaire". The prototype fixture shown to Genesis in 1980 was re-designated the "VL-zero" in the mid-1990s to keep the naming consistent. In 1985, the first moving head to use the DMX protocol was produced by Summa Technologies. Up until that time, moving lights were using other communication protocols, such as DIN8, AMX, D54 and the proprietary protocols of other companies, such as VariLite, High End and Coemar; the Summa HTI had a 250 W HTI bulb, two colour wheels, a gobo wheel, a mechanical dimmer and zoom functions.
The first purchasable/mass-produced scanner was the Coemar Robot, first produced in 1986. Produced with either the GE MARC350 lamp, or the Philips SN250. Versions were factory equipped with the Osram HTI400, a modification that High End Systems had been doing since 1987; the Robot used model aircraft servo motors to control Pan, Tilt and Gobo, with the gobo wheel providing the shutter function as well. The Color wheel had 4 dichroic color filters, the gobo wheel contained 4 stamped patterns; the Robot communicated with a proprietary 8bit protocol, yet had no microprocessors/pal's/pics/ram, O/S or other modern logic device. In 1987, Clay Paky began producing their first scanners, the Golden Scan 1 & Crystal Scan, they utilized stepper motors instead of servos and used a HMI 575 lamp and with a far more uniform beam brightness. This was followed by the Intellabeam in 1989, released by High End, who, at the time were the Distributors for Clay Paky. In the 1990s, the future came closer with Martin, a Danish Company that produced fog machines.
They began to manufacture a line of scanners known as Roboscans, with a variety of different specifications for different users. They were named for their wattages, with a range starting with 1004 and 1016. Came the 804 and 805, designed for small venues. Other models were the 218, 518, 812, 918 and 1200Pro units. Martin al
The fleur-de-lis or fleur-de-lys is a stylized lily, used as a decorative design or motif. Many of the Catholic saints of France St. Joseph, are depicted with a lily. Since France is a Catholic nation, the fleur-de-lis became "at one and the same time, political, artistic and symbolic" in French heraldry; the fleur-de-lis is represented in Unicode at U+269C in the Miscellaneous Symbols block. While the fleur-de-lis has appeared on countless European coats of arms and flags over the centuries, it is associated with the French monarchy in a historical context, continues to appear in the arms of the King of Spain and the Grand Duke of Luxembourg and members of the House of Bourbon, it remains an enduring symbol of France which appears on French postage stamps, although it has never been adopted by any of the French republics. According to French historian Georges Duby, the three petals represent the three medieval social estates: the commoners, the nobility, the clergy, it remains unclear where the fleur-de-lis originated, though it has retained an association with French nobility.
It is used in French city emblems as in the coat of arms of the city of Lille, Saint-Denis, Clermont-Ferrand, Boulogne-Billancourt and Calais. Some cities, faithful to the French Crown were awarded a heraldic augmentation of two or three fleurs-de-lis on the chief of their coat of arms; the fleur-de-lis was the symbol of the core of the French kingdom. It has appeared on the coat-of-arms of other historical provinces of France including Burgundy, Picardy, Orléanais, Maine, Artois, Dauphiné, Saintonge and the County of La Marche. Many of the current French departments use the symbol on their coats-of-arms to express this heritage. In Italy, the fleur de lis, called giglio, is known from the crest of the city of Florence. In the Florentine fleurs-de-lis, the stamens are always posed between the petals. Argent on gules background, the emblem became the standard of the imperial party in Florence, causing the town government, which maintained a staunch Guelph stance, being opposed to the imperial pretensions on city states, to reverse the color pattern to the final gules lily on argent background.
This heraldic charge is known as the Florentine lily to distinguish it from the conventional design. As an emblem of the city, it is therefore found in icons of Zenobius, its first bishop, associated with Florence's patron Saint John the Baptist in the Florentine fiorino. Several towns subjugated by Florence or founded within the territory of the Florentine Republic adopted a variation of the Florentine lily in their crests without the stamens; the heraldic fleur-de-lis is still widespread: among the numerous cities which use it as a symbol are some whose names echo the word'lily', for example, Liljendal and Lelystad, Netherlands. This is called canting arms in heraldic terminology. Other European examples of municipal coats-of-arms bearing the fleur-de-lis include Lincoln in England, Morcín in Spain, Wiesbaden in Germany, Skierniewice in Poland and Jurbarkas in Lithuania; the Swiss municipality of Schlieren and the Estonian municipality of Jõelähtme have a fleur-de-lis on their coats. In Malta, the town of Santa Venera has three red fleurs-de-lis on its coat of arms.
These are derived from an arch, part of the Wignacourt Aqueduct that had three sculpted fleurs-de-lis on top, as they were the heraldic symbols of Alof de Wignacourt, the Grand Master who financed its building. Another suburb which developed around the area became known as Fleur-de-Lys, it features a red fleur-de-lis on its flag and coat of arms; the coat of arms of the medieval Kingdom of Bosnia contained six fleurs-de-lis, understood as the native Bosnian or Golden Lily, Lilium bosniacum. This emblem was revived in 1992 as a national symbol of the Republic of Bosnia and Herzegovina and was the flag of Bosnia-Herzegovina from 1992 to 1998; the state insignia were changed in 1999. The former flag of the Federation of Bosnia and Herzegovina contains a fleur-de-lis alongside the Croatian chequy. Fleurs appear in the flags and arms of many cantons, municipalities and towns, it is still used as official insignia of the Bosniak Regiment of the Armed Forces of Bosnia and Herzegovina. In the United Kingdom, a fleur-de-lis has appeared in the official arms of the Norroy King of Arms for hundreds of years.
A silver fleur-de-lis on a blue background is the arms of the Barons Digby. In English and Canadian heraldry the fleur-de-lis is the cadence mark of a sixth son. In Mauritius, slaves were branded with a fleur-de-lis, when being punished for escaping or stealing food; the Welsh poet Hedd Wyn used Fleur de Lys as his pen name when he won his chair at the National Eisteddfod of Wales, the national poetry contest. Fleurs-de-lis appear on the logos of many organizations. During the 20th century the symbol was adopted by various Scouting organizations worldwide for their badges. Architects and designers use it alone and as a repeated motif in a wide range of contexts, from ironwork to bookbinding where a French context is implied; the symbol is often used on a compass rose to mark the north direction, a tradition started
Light is electromagnetic radiation within a certain portion of the electromagnetic spectrum. The word refers to visible light, the visible spectrum, visible to the human eye and is responsible for the sense of sight. Visible light is defined as having wavelengths in the range of 400–700 nanometres, or 4.00 × 10−7 to 7.00 × 10−7 m, between the infrared and the ultraviolet. This wavelength means a frequency range of 430–750 terahertz; the main source of light on Earth is the Sun. Sunlight provides the energy that green plants use to create sugars in the form of starches, which release energy into the living things that digest them; this process of photosynthesis provides all the energy used by living things. Another important source of light for humans has been fire, from ancient campfires to modern kerosene lamps. With the development of electric lights and power systems, electric lighting has replaced firelight; some species of animals generate their own light, a process called bioluminescence.
For example, fireflies use light to locate mates, vampire squids use it to hide themselves from prey. The primary properties of visible light are intensity, propagation direction, frequency or wavelength spectrum, polarization, while its speed in a vacuum, 299,792,458 metres per second, is one of the fundamental constants of nature. Visible light, as with all types of electromagnetic radiation, is experimentally found to always move at this speed in a vacuum. In physics, the term light sometimes refers to electromagnetic radiation of any wavelength, whether visible or not. In this sense, gamma rays, X-rays and radio waves are light. Like all types of EM radiation, visible light propagates as waves. However, the energy imparted by the waves is absorbed at single locations the way particles are absorbed; the absorbed energy of the EM waves is called a photon, represents the quanta of light. When a wave of light is transformed and absorbed as a photon, the energy of the wave collapses to a single location, this location is where the photon "arrives."
This is. This dual wave-like and particle-like nature of light is known as the wave–particle duality; the study of light, known as optics, is an important research area in modern physics. EM radiation, or EMR, is classified by wavelength into radio waves, infrared, the visible spectrum that we perceive as light, ultraviolet, X-rays, gamma rays; the behavior of EMR depends on its wavelength. Higher frequencies have shorter wavelengths, lower frequencies have longer wavelengths; when EMR interacts with single atoms and molecules, its behavior depends on the amount of energy per quantum it carries. EMR in the visible light region consists of quanta that are at the lower end of the energies that are capable of causing electronic excitation within molecules, which leads to changes in the bonding or chemistry of the molecule. At the lower end of the visible light spectrum, EMR becomes invisible to humans because its photons no longer have enough individual energy to cause a lasting molecular change in the visual molecule retinal in the human retina, which change triggers the sensation of vision.
There exist animals that are sensitive to various types of infrared, but not by means of quantum-absorption. Infrared sensing in snakes depends on a kind of natural thermal imaging, in which tiny packets of cellular water are raised in temperature by the infrared radiation. EMR in this range causes molecular vibration and heating effects, how these animals detect it. Above the range of visible light, ultraviolet light becomes invisible to humans because it is absorbed by the cornea below 360 nm and the internal lens below 400 nm. Furthermore, the rods and cones located in the retina of the human eye cannot detect the short ultraviolet wavelengths and are in fact damaged by ultraviolet. Many animals with eyes that do not require lenses are able to detect ultraviolet, by quantum photon-absorption mechanisms, in much the same chemical way that humans detect visible light. Various sources define visible light as narrowly as 420–680 nm to as broadly as 380–800 nm. Under ideal laboratory conditions, people can see infrared up to at least 1050 nm.
Plant growth is affected by the color spectrum of light, a process known as photomorphogenesis. The speed of light in a vacuum is defined to be 299,792,458 m/s; the fixed value of the speed of light in SI units results from the fact that the metre is now defined in terms of the speed of light. All forms of electromagnetic radiation move at this same speed in vacuum. Different physicists have attempted to measure the speed of light throughout history. Galileo attempted to measure the speed of light in the seventeenth century. An early experiment to measure the speed of light was conducted by Ole Rømer, a Danish physicist, in 1676. Using a telescope, Rømer observed one of its moons, Io. Noting discrepancies in the apparent period of Io's orbit, he calculated that light takes about 22 minutes to traverse the diameter of Earth's orbit. However, its size was not known at that time. If Rømer had known the diameter of the Earth's orbit, he would have calculated a speed of 227,000,000 m/s. Another, more accurate, measurement of the speed of light was performed in Europe by Hippolyte Fizeau in 1849.