131-418: Stained glass is colored glass as a material or works created from it. Although, it is traditionally made in flat panels and used as windows, the creations of modern stained glass artists also include three-dimensional structures and sculpture . Modern vernacular usage has often extended the term "stained glass" to include domestic lead light and objets d'art created from foil glasswork exemplified in
262-405: A glass (or vitreous solid) is a non-crystalline solid formed by rapid melt quenching . However, the term "glass" is often defined in a broader sense, to describe any non-crystalline ( amorphous ) solid that exhibits a glass transition when heated towards the liquid state. Glass is an amorphous solid . Although the atomic-scale structure of glass shares characteristics of the structure of
393-466: A lead lattice work and fitted into the window frame. Crown glass was one of the two most common processes for making window glass until the 19th century. The other was blown plate . Crown glass window panes with ceramic frames have been found at Soba East , the medieval capital of Alodia . They are only 110–115 millimetres (4.3–4.5 in) in diameter and were probably used to provide light in storerooms. The process of making crown glass window panes
524-436: A supercooled liquid , glass exhibits all the mechanical properties of a solid. As in other amorphous solids , the atomic structure of a glass lacks the long-range periodicity observed in crystalline solids . Due to chemical bonding constraints, glasses do possess a high degree of short-range order with respect to local atomic polyhedra . The notion that glass flows to an appreciable extent over extended periods well below
655-809: A turquoise colour in glass, in contrast to copper(I) oxide (Cu 2 O) which gives a dull red-brown colour. Soda–lime sheet glass is typically used as a transparent glazing material, typically as windows in external walls of buildings. Float or rolled sheet glass products are cut to size either by scoring and snapping the material, laser cutting , water jets , or diamond-bladed saw. The glass may be thermally or chemically tempered (strengthened) for safety and bent or curved during heating. Surface coatings may be added for specific functions such as scratch resistance, blocking specific wavelengths of light (e.g. infrared or ultraviolet ), dirt-repellence (e.g. self-cleaning glass ), or switchable electrochromic coatings. Structural glazing systems represent one of
786-479: A brushable texture, with a binder such as gum arabic . This was painted on the pieces of coloured glass, and then fired to burn away the ingredients giving texture, leaving a layer of the glass and colouring, fused to the main glass piece. "Silver stain", introduced soon after 1300, produced a wide range of yellow to orange colours; this is the "stain" in the term "stained glass". Silver compounds (notably silver nitrate ) are mixed with binding substances, applied to
917-485: A clear "ring" sound when struck. However, lead glass cannot withstand high temperatures well. Lead oxide also facilitates the solubility of other metal oxides and is used in coloured glass. The viscosity decrease of lead glass melt is very significant (roughly 100 times in comparison with soda glass); this allows easier removal of bubbles and working at lower temperatures, hence its frequent use as an additive in vitreous enamels and glass solders . The high ionic radius of
1048-520: A different colour). In medieval glass flashing was especially used for reds, as glass made with gold compounds was very expensive and tended to be too deep in colour to use at full thickness. Another group of techniques give additional colouring, including lines and shading, by treating the surfaces of the coloured sheets, and often fixing these effects by a light firing in a furnace or kiln. These methods may be used over broad areas, especially with silver stain, which gave better yellows than other methods in
1179-761: A great demand for the revival of the art of stained glass window making. Among the earliest 19th-century English manufacturers and designers were William Warrington and John Hardman of Birmingham, whose nephew, John Hardman Powell, had a commercial eye and exhibited works at the Philadelphia Exhibition of 1876, influencing stained glass in the United States of America. Other manufacturers included William Wailes , Ward and Hughes , Clayton and Bell , Heaton, Butler and Bayne and Charles Eamer Kempe . A Scottish designer, Daniel Cottier , opened firms in Australia and
1310-443: A green tint in thick sections. Manganese dioxide (MnO 2 ), which gives glass a purple colour, may be added to remove the green tint given by FeO. FeO and chromium(III) oxide (Cr 2 O 3 ) additives are used in the production of green bottles. Iron (III) oxide , on the other-hand, produces yellow or yellow-brown glass. Low concentrations (0.025 to 0.1%) of cobalt oxide (CoO) produce rich, deep blue cobalt glass . Chromium
1441-408: A human timescale. Silicon dioxide (SiO 2 ) is a common fundamental constituent of glass. Fused quartz is a glass made from chemically pure silica. It has very low thermal expansion and excellent resistance to thermal shock , being able to survive immersion in water while red hot, resists high temperatures (1000–1500 °C) and chemical weathering, and is very hard. It is also transparent to
SECTION 10
#17330928108701572-405: A lighter alternative to traditional glass. Molecular liquids, electrolytes , molten salts , and aqueous solutions are mixtures of different molecules or ions that do not form a covalent network but interact only through weak van der Waals forces or transient hydrogen bonds . In a mixture of three or more ionic species of dissimilar size and shape, crystallization can be so difficult that
1703-561: A long period at a temperature just insufficient to cause fusion. In this way, the crystalline, devitrified material, known as Réaumur's glass porcelain is produced. Although generally transparent to visible light, glasses may be opaque to other wavelengths of light . While silicate glasses are generally opaque to infrared wavelengths with a transmission cut-off at 4 μm, heavy-metal fluoride and chalcogenide glasses are transparent to infrared wavelengths of 7 to 18 μm. The addition of metallic oxides results in different coloured glasses as
1834-517: A market across Europe, in America and Australia. Stained glass studios were also founded in Italy and Belgium at this time. Glass Glass is an amorphous ( non-crystalline ) solid. Because it is often transparent and chemically inert, glass has found widespread practical, technological, and decorative use in window panes, tableware , and optics . Some common objects made of glass are named after
1965-482: A mass of hot semi-molten glass, inflating it into a bubble using a hollow blowpipe, and forming it into the required shape by blowing, swinging, rolling, or moulding. While hot, the glass can be worked using hand tools, cut with shears, and additional parts such as handles or feet attached by welding. Flat glass for windows and similar applications is formed by the float glass process, developed between 1953 and 1957 by Sir Alastair Pilkington and Kenneth Bickerstaff of
2096-454: A more Classical manner, and characterised by the brilliant cerulean colour of the blue backgrounds (as against the purple-blue of the glass of Chartres) and the use of pink and mauve glass. During the mid- to late 19th century, many of Germany's ancient buildings were restored, and some, such as Cologne Cathedral , were completed in the medieval style. There was a great demand for stained glass. The designs for many windows were based directly on
2227-453: A non-crystalline intergranular phase of grain boundaries . Glass-ceramics exhibit advantageous thermal, chemical, biological, and dielectric properties as compared to metals or organic polymers. The most commercially important property of glass-ceramics is their imperviousness to thermal shock. Thus, glass-ceramics have become extremely useful for countertop cooking and industrial processes. The negative thermal expansion coefficient (CTE) of
2358-438: A number of resources to use and the work of centuries of other artists from which to learn as they continue the tradition in new ways. In the late 19th and 20th centuries there have been many innovations in techniques and in the types of glass used. Many new types of glass have been developed for use in stained glass windows, in particular Tiffany glass and dalle de verre . The primary method of including colour in stained glass
2489-401: A plastic resin with glass fibres . It is made by melting glass and stretching the glass into fibres. These fibres are woven together into a cloth and left to set in a plastic resin. Fibreglass has the properties of being lightweight and corrosion resistant and is a good insulator enabling its use as building insulation material and for electronic housing for consumer products. Fibreglass
2620-462: A refractive index of 1.4 to 2.4, and an Abbe number (which characterises dispersion) of 15 to 100. The refractive index may be modified by high-density (refractive index increases) or low-density (refractive index decreases) additives. Glass transparency results from the absence of grain boundaries which diffusely scatter light in polycrystalline materials. Semi-opacity due to crystallization may be induced in many glasses by maintaining them for
2751-442: A rigid frame. Painted details and yellow stain are often used to enhance the design. The term stained glass is also applied to windows in enamelled glass in which the colors have been painted onto the glass and then fused to the glass in a kiln; very often this technique is only applied to parts of a window. Stained glass, as an art and a craft , requires the artistic skill to conceive an appropriate and workable design, and
SECTION 20
#17330928108702882-641: A slightly mauve tint, characteristic of the glass in older houses in New England . Selenium has been used for the same purpose. While very pale green is the typical colour of transparent glass, deeper greens can be achieved by the addition of Iron(II) oxide which results in a bluish-green glass. Together with chromium it gives glass of a richer green colour, typical of the glass used to make wine bottles . The addition of chromium yields dark green glass, suitable for flashed glass. Together with tin oxide and arsenic it yields emerald green glass. The first stage in
3013-412: A spinning metal disk. Several alloys have been produced in layers with thicknesses exceeding 1 millimetre. These are known as bulk metallic glasses (BMG). Liquidmetal Technologies sells several zirconium -based BMGs. Batches of amorphous steel have also been produced that demonstrate mechanical properties far exceeding those found in conventional steel alloys. Experimental evidence indicates that
3144-409: A stain known as "Cousin's rose" was used to enhance flesh tones. In the 16th century, a range of glass stains were introduced, most of them coloured by ground glass particles. They were a form of enamelled glass . Painting on glass with these stains was initially used for small heraldic designs and other details. By the 17th century a style of stained glass had evolved that was no longer dependent upon
3275-435: A structural analogue of silica, fluoride , aluminate , phosphate , borate , and chalcogenide glasses) have physicochemical properties useful for their application in fibre-optic waveguides in communication networks and other specialised technological applications. Silica-free glasses may often have poor glass-forming tendencies. Novel techniques, including containerless processing by aerodynamic levitation (cooling
3406-413: A structurally metastable state with respect to its crystalline form, although in certain circumstances, for example in atactic polymers, there is no crystalline analogue of the amorphous phase. Glass is sometimes considered to be a liquid due to its lack of a first-order phase transition where certain thermodynamic variables such as volume , entropy and enthalpy are discontinuous through
3537-423: A thin layer of red glass to a thicker body of glass that is clear or lightly tinted, forming " flashed glass ". A lightly coloured molten gather is dipped into a pot of molten red glass, which is then blown into a sheet of laminated glass using either the cylinder (muff) or the crown technique described above. Once this method was found for making red glass, other colours were made this way as well. A great advantage
3668-491: A traditional type, it is usually left to the discretion of the designer to fill the surrounding areas with borders, floral motifs and canopies. A full-sized cartoon is drawn for every "light" (opening) of the window. A small church window might typically have two lights, with some simple tracery lights above. A large window might have four or five lights. The east or west window of a large cathedral might have seven lights in three tiers, with elaborate tracery. In medieval times
3799-518: A wider spectral range than ordinary glass, extending from the visible further into both the UV and IR ranges, and is sometimes used where transparency to these wavelengths is necessary. Fused quartz is used for high-temperature applications such as furnace tubes, lighting tubes, melting crucibles, etc. However, its high melting temperature (1723 °C) and viscosity make it difficult to work with. Therefore, normally, other substances (fluxes) are added to lower
3930-418: Is 3.25 × 10 /°C as compared to about 9 × 10 /°C for a typical soda–lime glass ). They are, therefore, less subject to stress caused by thermal expansion and thus less vulnerable to cracking from thermal shock . They are commonly used for e.g. labware , household cookware , and sealed beam car head lamps . The addition of lead(II) oxide into silicate glass lowers the melting point and viscosity of
4061-552: Is a common volcanic glass with high silica (SiO 2 ) content formed when felsic lava extruded from a volcano cools rapidly. Impactite is a form of glass formed by the impact of a meteorite , where Moldavite (found in central and eastern Europe), and Libyan desert glass (found in areas in the eastern Sahara , the deserts of eastern Libya and western Egypt ) are notable examples. Vitrification of quartz can also occur when lightning strikes sand , forming hollow, branching rootlike structures called fulgurites . Trinitite
Stained glass - Misplaced Pages Continue
4192-702: Is a glassy residue formed from the desert floor sand at the Trinity nuclear bomb test site. Edeowie glass , found in South Australia , is proposed to originate from Pleistocene grassland fires, lightning strikes, or hypervelocity impact by one or several asteroids or comets . Naturally occurring obsidian glass was used by Stone Age societies as it fractures along very sharp edges, making it ideal for cutting tools and weapons. Glassmaking dates back at least 6000 years, long before humans had discovered how to smelt iron. Archaeological evidence suggests that
4323-528: Is a murky mustard color but glows purple-red to transmitted light, and the cameo glass Portland vase which is midnight blue, with a carved white overlay. In early Christian churches of the 4th and 5th centuries, there are many remaining windows which are filled with ornate patterns of thinly-sliced alabaster set into wooden frames, giving a stained-glass like effect. Evidence of stained-glass windows in churches and monasteries in Britain can be found as early as
4454-418: Is a very powerful colouring agent, yielding dark green. Sulphur combined with carbon and iron salts produces amber glass ranging from yellowish to almost black. A glass melt can also acquire an amber colour from a reducing combustion atmosphere. Cadmium sulfide produces imperial red , and combined with selenium can produce shades of yellow, orange, and red. Addition of copper(II) oxide (CuO) produces
4585-449: Is achieved by homogenizing the raw materials mixture ( glass batch ), stirring the melt, and crushing and re-melting the first melt. The obtained glass is usually annealed to prevent breakage during processing. Colour in glass may be obtained by addition of homogenously distributed electrically charged ions (or colour centres ). While ordinary soda–lime glass appears colourless in thin section, iron(II) oxide (FeO) impurities produce
4716-402: 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, and gold produces wine red and violet glass. Much of modern red glass is produced using copper, which is less expensive than gold and gives a brighter, more vermilion shade of red. Glass coloured while in the clay pot in the furnace
4847-676: Is extensively used for fibreglass , used for making glass-reinforced plastics (boats, fishing rods, etc.), top-of-stove cookware, and halogen bulb glass. The addition of barium also increases the refractive index. Thorium oxide gives glass a high refractive index and low dispersion and was formerly used in producing high-quality lenses, but due to its radioactivity has been replaced by lanthanum oxide in modern eyeglasses. Iron can be incorporated into glass to absorb infrared radiation, for example in heat-absorbing filters for movie projectors, while cerium(IV) oxide can be used for glass that absorbs ultraviolet wavelengths. Fluorine lowers
4978-455: Is in widespread use in optical systems due to its ability to refract, reflect, and transmit light following geometrical optics . The most common and oldest applications of glass in optics are as lenses , windows , mirrors , and prisms . The key optical properties refractive index , dispersion , and transmission , of glass are strongly dependent on chemical composition and, to a lesser degree, its thermal history. Optical glass typically has
5109-481: Is incorrect, as once solidified, glass stops flowing. The sags and ripples observed in old glass were already there the day it was made; manufacturing processes used in the past produced sheets with imperfect surfaces and non-uniform thickness (the near-perfect float glass used today only became widespread in the 1960s). A 2017 study computed the rate of flow of the medieval glass used in Westminster Abbey from
5240-418: Is known as pot metal glass, as opposed to flashed glass . Using a blow-pipe , a glass maker will gather a glob of molten glass that was taken from the pot heating in the furnace. The 'gather' is formed to the correct shape and a bubble of air blown into it. Using metal tools, molds of wood that have been soaking in water, and gravity, the gather is manipulated to form a long, cylindrical shape. As it cools, it
5371-446: Is now sometimes used instead of lead. For further technical details, see Came glasswork . Traditionally, when a window was inserted into the window space, iron rods were put across it at various points to support its weight. The window was tied to these rods with lead strips or, more recently, with copper wires. Some very large early Gothic windows are divided into sections by heavy metal frames called ferramenta . This method of support
Stained glass - Misplaced Pages Continue
5502-901: Is produced by forcing molten glass through a fine mesh by centripetal force and breaking the extruded glass fibres into short lengths using a stream of high-velocity air. The fibres are bonded with an adhesive spray and the resulting wool mat is cut and packed in rolls or panels. Besides common silica-based glasses many other inorganic and organic materials may also form glasses, including metals , aluminates , phosphates , borates , chalcogenides , fluorides , germanates (glasses based on GeO 2 ), tellurites (glasses based on TeO 2 ), antimonates (glasses based on Sb 2 O 3 ), arsenates (glasses based on As 2 O 3 ), titanates (glasses based on TiO 2 ), tantalates (glasses based on Ta 2 O 5 ), nitrates , carbonates , plastics , acrylic , and many other substances. Some of these glasses (e.g. Germanium dioxide (GeO 2 , Germania), in many respects
5633-458: Is reheated so that the manipulation can continue. 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, and the cylinder is then put into another oven to quickly heat and flatten it, and then placed in an annealer to cool at a controlled rate, making the material more stable. "Hand-blown" or "mouth-blown" cylinder (also called muff glass) and crown glass were
5764-415: Is still made today, but not on a large scale. Rolled glass (sometimes called "table glass") is produced by pouring molten glass onto a metal or graphite table and immediately rolling it into a sheet using a large metal cylinder, similar to rolling out a pie crust. The rolling can be done by hand or by machine. Glass can be "double rolled", which means it is passed through two cylinders at once (similar to
5895-461: Is stronger than most metals, with a theoretical tensile strength for pure, flawless glass estimated at 14 to 35 gigapascals (2,000,000 to 5,100,000 psi) due to its ability to undergo reversible compression without fracture. However, the presence of scratches, bubbles, and other microscopic flaws lead to a typical range of 14 to 175 megapascals (2,000 to 25,400 psi) in most commercial glasses. Several processes such as toughening can increase
6026-408: Is sufficiently rapid (relative to the characteristic crystallization time) then crystallization is prevented and instead, the disordered atomic configuration of the supercooled liquid is frozen into the solid state at T g . The tendency for a material to form a glass while quenched is called glass-forming ability. This ability can be predicted by the rigidity theory . Generally, a glass exists in
6157-468: Is that the double-layered glass can be engraved or abraded to reveal the clear or tinted glass below. The method allows rich detailing and patterns to be achieved without needing to add more lead-lines, giving artists greater freedom in their designs. A number of artists have embraced the possibilities flashed glass gives them. For instance, 16th-century heraldic windows relied heavily on a variety of flashed colours for their intricate crests and creatures. In
6288-411: Is to use glass, originally colourless, that has been given colouring by mixing with metal oxides in its melted state (in a crucible or "pot"), producing glass sheets that are coloured all the way through; these are known as "pot metal" glass. A second method, sometimes used in some areas of windows, is flashed glass , a thin coating of coloured glass fused to colourless glass (or coloured glass, to produce
6419-436: Is transparent, easily formed, and most suitable for window glass and tableware. However, it has a high thermal expansion and poor resistance to heat. Soda–lime glass is typically used for windows , bottles , light bulbs , and jars . Borosilicate glasses (e.g. Pyrex , Duran ) typically contain 5–13% boron trioxide (B 2 O 3 ). Borosilicate glasses have fairly low coefficients of thermal expansion (7740 Pyrex CTE
6550-709: The Aube department alone. At the Reformation in England, large numbers of medieval and Renaissance windows were smashed and replaced with plain glass. The Dissolution of the Monasteries under Henry VIII and the injunctions of Thomas Cromwell against "abused images" (the object of veneration) resulted in the loss of thousands of windows. Few remain undamaged; of these the windows in the private chapel at Hengrave Hall in Suffolk are among
6681-460: The Bible , history, or literature; may represent saints or patrons, or use symbolic motifs, in particular armorial. Windows within a building may be thematic, for example: within a church – episodes from the life of Christ ; within a parliament building – shields of the constituencies; within a college hall – figures representing the arts and sciences; or within a home – flora, fauna, or landscape. During
SECTION 50
#17330928108706812-467: The French Revolution . During the 19th century a great number of churches were restored by Viollet-le-Duc . Many of France's finest ancient windows were restored at that time. From 1839 onwards much stained glass was produced that very closely imitated medieval glass, both in the artwork and in the nature of the glass itself. The pioneers were Henri Gèrente and André Lusson. Other glass was designed in
6943-513: The Late Bronze Age , there was a rapid growth in glassmaking technology in Egypt and Western Asia . Archaeological finds from this period include coloured glass ingots , vessels, and beads. Much early glass production relied on grinding techniques borrowed from stoneworking , such as grinding and carving glass in a cold state. The term glass has its origins in the late Roman Empire , in
7074-525: The Renaissance period in Europe, the use of large stained glass windows became much less prevalent, although stained glass had a major revival with Gothic Revival architecture in the 19th century. During the 13th century, the island of Murano , Venice , became a centre for glass making, building on medieval techniques to produce colourful ornamental pieces in large quantities. Murano glass makers developed
7205-527: The Roman glass making centre at Trier (located in current-day Germany) where the late-Latin term glesum originated, likely from a Germanic word for a transparent , lustrous substance. Glass objects have been recovered across the Roman Empire in domestic, funerary , and industrial contexts, as well as trade items in marketplaces in distant provinces. Examples of Roman glass have been found outside of
7336-465: The dielectric constant of glass. Fluorine is highly electronegative and lowers the polarizability of the material. Fluoride silicate glasses are used in the manufacture of integrated circuits as an insulator. Glass-ceramic materials contain both non-crystalline glass and crystalline ceramic phases. They are formed by controlled nucleation and partial crystallisation of a base glass by heat treatment. Crystalline grains are often embedded within
7467-436: The glass batch preparation and mixing, the raw materials are transported to the furnace. Soda–lime glass for mass production is melted in glass-melting furnaces . Smaller-scale furnaces for speciality glasses include electric melters, pot furnaces, and day tanks. After melting, homogenization and refining (removal of bubbles), the glass is formed . This may be achieved manually by glassblowing , which involves gathering
7598-402: The "Bishop's Eye" at Lincoln Cathedral . While stained glass was widely manufactured, Chartres was the greatest centre of stained glass manufacture, producing glass of unrivalled quality. Probably the earliest scheme of stained glass windows that was created during the Renaissance was that for Florence Cathedral, devised by Lorenzo Ghiberti . The scheme includes three ocular windows for
7729-501: The 10th century onwards, glass was employed in stained glass windows of churches and cathedrals , with famous examples at Chartres Cathedral and the Basilica of Saint-Denis . By the 14th century, architects were designing buildings with walls of stained glass such as Sainte-Chapelle , Paris, (1203–1248) and the East end of Gloucester Cathedral . With the change in architectural style during
7860-461: The 1930s, which later became known as Depression glass . In the 1950s, Pilkington Bros. , England , developed the float glass process, producing high-quality distortion-free flat sheets of glass by floating on molten tin . Modern multi-story buildings are frequently constructed with curtain walls made almost entirely of glass. Laminated glass has been widely applied to vehicles for windscreens. Optical glass for spectacles has been used since
7991-455: The 7th century. The earliest known reference dates from 675 AD when Benedict Biscop imported workmen from France to glaze the windows of the monastery of St Peter which he was building at Monkwearmouth . Hundreds of pieces of coloured glass and lead, dating back to the late 7th century, have been discovered here and at Jarrow . In the Middle East, the glass industry of Syria continued during
SECTION 60
#17330928108708122-469: The 7th-century BC. The Kitab al-Durra al-Maknuna , attributed to the 8th century alchemist Jābir ibn Hayyān , discusses the production of colored glass in ancient Babylon and Egypt. The Kitab al-Durra al-Maknuna also describes how to create colored glass and artificial gemstones made from high-quality stained glass. The tradition of stained glass manufacture has continued, with mosques, palaces, and public spaces being decorated with stained glass throughout
8253-715: The Basílica Nuestra Señora de Lourde and the Templo Vótivo de Maipú both located in Chile. The Catholic revival in England, gaining force in the early 19th century with its renewed interest in the medieval church, brought a revival of church building in the Gothic style, claimed by John Ruskin to be "the true Catholic style". The architectural movement was led by Augustus Welby Pugin . Many new churches were planted in large towns and many old churches were restored. This brought about
8384-583: The Islamic period with major centres of manufacture at Raqqa , Aleppo and Damascus and the most important products being highly transparent colourless glass and gilded glass, rather than coloured glass. The creation of stained glass in Southwest Asia began in ancient times. One of the region's earliest surviving formulations for the production of colored glass comes from the Assyrian city of Nineveh , dating to
8515-554: The Islamic world. The stained glass of Islam is generally non-pictorial and of purely geometric design, but may contain both floral motifs and text. Stained glass creation had flourished in Persia (now Iran) during the Safavid dynasty (1501–1736 A.D.), and Zand dynasty (1751–1794 A.D.). In Persia stained glass sash windows are called Orosi windows (or transliterated as Arasi, and Orsi), and were once used for decoration, as well as controlling
8646-681: The Middle Ages. The production of lenses has become increasingly proficient, aiding astronomers as well as having other applications in medicine and science. Glass is also employed as the aperture cover in many solar energy collectors. In the 21st century, glass manufacturers have developed different brands of chemically strengthened glass for widespread application in touchscreens for smartphones , tablet computers , and many other types of information appliances . These include Gorilla Glass , developed and manufactured by Corning , AGC Inc. 's Dragontrail and Schott AG 's Xensation. Glass
8777-433: The Middle Ages. Alternatively they may be used for painting linear effects, or polychrome areas of detail. The most common method of adding the black linear painting necessary to define stained glass images is the use of what is variously called "glass paint", "vitreous paint", or " grisaille paint". This was applied as a mixture of powdered glass, iron or rust filings to give a black colour, clay, and oil, vinegar or water for
8908-540: The Pb ion renders it highly immobile and hinders the movement of other ions; lead glasses therefore have high electrical resistance, about two orders of magnitude higher than soda–lime glass (10 vs 10 Ω⋅cm, DC at 250 °C). Aluminosilicate glass typically contains 5–10% alumina (Al 2 O 3 ). Aluminosilicate glass tends to be more difficult to melt and shape compared to borosilicate compositions but has excellent thermal resistance and durability. Aluminosilicate glass
9039-530: The UK's Pilkington Brothers, who created a continuous ribbon of glass using a molten tin bath on which the molten glass flows unhindered under the influence of gravity. The top surface of the glass is subjected to nitrogen under pressure to obtain a polished finish. Container glass for common bottles and jars is formed by blowing and pressing methods. This glass is often slightly modified chemically (with more alumina and calcium oxide) for greater water resistance. Once
9170-546: The US. In France there was a greater continuity of stained glass production than in England. In the early 19th century most stained glass was made of large panes that were extensively painted and fired, the designs often being copied directly from oil paintings by famous artists. In 1824 the Sèvres porcelain factory began producing stained glass to supply the increasing demand. In France many churches and cathedrals suffered despoliation during
9301-719: The action of water, making it an ideal material for the manufacture of containers for foodstuffs and most chemicals. Nevertheless, although usually highly resistant to chemical attack, glass will corrode or dissolve under some conditions. The materials that make up a particular glass composition affect how quickly the glass corrodes. Glasses containing a high proportion of alkali or alkaline earth elements are more susceptible to corrosion than other glass compositions. The density of glass varies with chemical composition with values ranging from 2.2 grams per cubic centimetre (2,200 kg/m ) for fused silica to 7.2 grams per cubic centimetre (7,200 kg/m ) for dense flint glass. Glass
9432-408: The cartoon was drawn directly on the surface of a whitewashed table, which was then used as a pattern for cutting, painting and assembling the window. The cartoon is then divided into a patchwork, providing a template for each small glass piece. The exact position of the lead which holds the glass in place is also noted, as it is part of the calculated visual effect. Each piece of glass is selected for
9563-473: The clothes wringers on older washing machines) to yield glass of a specified thickness (typically about 1/8" or 3mm). The glass is then annealed. Rolled glass was first commercially produced around the mid-1830s and is widely used today. It is often called cathedral glass , but this has nothing to do with medieval cathedrals, where the glass used was hand-blown. Architectural glass must be at least 1 / 8 of an inch (3 mm) thick to survive
9694-411: The cost factor has a low priority. In the laboratory mostly pure chemicals are used. Care must be taken that the raw materials have not reacted with moisture or other chemicals in the environment (such as alkali or alkaline earth metal oxides and hydroxides, or boron oxide ), or that the impurities are quantified (loss on ignition). Evaporation losses during glass melting should be considered during
9825-427: The crystalline ceramic phase can be balanced with the positive CTE of the glassy phase. At a certain point (~70% crystalline) the glass-ceramic has a net CTE near zero. This type of glass-ceramic exhibits excellent mechanical properties and can sustain repeated and quick temperature changes up to 1000 °C. Fibreglass (also called glass fibre reinforced plastic, GRP) is a composite material made by reinforcing
9956-698: The cupola windows has since been lost, and that by Donatello has lost nearly all of its painted details. In Europe, stained glass continued to be produced; the style evolved from the Gothic to the Classical, which is well represented in Germany, Belgium and the Netherlands, despite the rise of Protestantism . In France, much glass of this period was produced at the Limoges factory, and in Italy at Murano , where stained glass and faceted lead crystal are often coupled together in
10087-399: The decorated surface to the atmosphere or mechanical damage. Once the glass is cut and painted, the pieces are assembled by slotting them into H-sectioned lead cames. All the joints are then soldered together and the glass pieces are prevented from rattling and the window made weatherproof by forcing a soft oily cement or mastic between the glass and the cames. In modern windows, copper foil
10218-409: The design, the structure of the window, the nature and size of the glass available and his or her own preferred technique. A traditional narrative window has panels which relate a story. A figurative window could have rows of saints or dignitaries. Scriptural texts or mottoes are sometimes included and perhaps the names of the patrons or the person to whose memory the window is dedicated. In a window of
10349-491: The desired colour and cut to match a section of the template. An exact fit is ensured by "grozing" the edges with a tool which can nibble off small pieces. Details of faces, hair and hands can be painted onto the inner surface of the glass using a special glass paint which contains finely ground lead or copper filings, ground glass, gum arabic and a medium such as wine, vinegar or (traditionally) urine. The art of painting details became increasingly elaborate and reached its height in
10480-683: The desired form is obtained, glass is usually annealed for the removal of stresses and to increase the glass's hardness and durability. Surface treatments, coatings or lamination may follow to improve the chemical durability ( glass container coatings , glass container internal treatment ), strength ( toughened glass , bulletproof glass , windshields ), or optical properties ( insulated glazing , anti-reflective coating ). New chemical glass compositions or new treatment techniques can be initially investigated in small-scale laboratory experiments. The raw materials for laboratory-scale glass melts are often different from those used in mass production because
10611-555: The dome and three for the facade which were designed from 1405 to 1445 by several of the most renowned artists of this period: Ghiberti , Donatello , Uccello and Andrea del Castagno . Each major ocular window contains a single picture drawn from the Life of Christ or the Life of the Virgin Mary , surrounded by a wide floral border, with two smaller facade windows by Ghiberti showing the martyred deacons, St Stephen and St Lawrence . One of
10742-578: The early 1600s; the earliest is the work of Dirck Crabeth and his brother Wouter . Many of the original cartoons still exist. Stained glass was first imported to Latin America during the 17th–18th centuries by Portuguese and Spanish settlers. By the 20th century, many European artists had begun to establish their own studios within Latin America and had started up local production. With these new local studios came inventive techniques and less traditional imagery. Examples of these more modern works of art are
10873-413: The early 20th century. From 1300 onwards, artists started using "silver stain" which was made with silver nitrate . It gave a yellow effect ranging from pale lemon to deep orange. It was usually painted onto the outside of a piece of glass, then fired to make it permanent. This yellow was particularly useful for enhancing borders, canopies and haloes, and turning blue glass into green glass. By about 1450,
11004-637: The eastern end of Canterbury Cathedral . As Gothic architecture developed into a more ornate form, windows grew larger, affording greater illumination to the interiors, but were divided into sections by vertical shafts and tracery of stone. This elaboration of form reached its height of complexity in the Flamboyant style in Europe, and windows grew still larger with the development of the Perpendicular style in England and Rayonnant style in France. Integrated with
11135-458: 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, and also, especially in the larger windows, must support its own weight. Many large windows have withstood the test of time and remained substantially intact since the Late Middle Ages . In Western Europe , together with illuminated manuscripts , they constitute
11266-462: The exceptionally clear colourless glass cristallo , so called for its resemblance to natural crystal, which was extensively used for windows, mirrors, ships' lanterns, and lenses. In the 13th, 14th, and 15th centuries, enamelling and gilding on glass vessels were perfected in Egypt and Syria. Towards the end of the 17th century, Bohemia became an important region for glass production, remaining so until
11397-435: The famous lamps of Louis Comfort Tiffany . As a material stained glass is glass that has been colored by adding metallic salts during its manufacture, and usually then further decorating it in various ways. The colored glass is crafted into stained glass windows in which small pieces of glass are arranged to form patterns or pictures, held together (traditionally) by strips of lead, called cames or calms, and supported by
11528-420: The finest. With the latter wave of destruction the traditional methods of working with stained glass died, and were not rediscovered in England until the early 19th century. See Stained glass – British glass, 1811–1918 for more details. In the Netherlands a rare scheme of glass has remained intact at Grote Sint-Jan Church, Gouda . The windows, some of which are 18 metres (59 feet) high, date from 1555 to
11659-454: The first true synthetic glass was made in Lebanon and the coastal north Syria , Mesopotamia or ancient Egypt . The earliest known glass objects, of the mid-third millennium BC, were beads , perhaps initially created as accidental by-products of metalworking ( slags ) or during the production of faience , a pre-glass vitreous material made by a process similar to glazing . Early glass
11790-733: The former Roman Empire in China , the Baltics , the Middle East , and India . The Romans perfected cameo glass , produced by etching and carving through fused layers of different colours to produce a design in relief on the glass object. In post-classical West Africa, Benin was a manufacturer of glass and glass beads. Glass was used extensively in Europe during the Middle Ages . Anglo-Saxon glass has been found across England during archaeological excavations of both settlement and cemetery sites. From
11921-555: The glass and melt phases. Important polymer glasses include amorphous and glassy pharmaceutical compounds. These are useful because the solubility of the compound is greatly increased when it is amorphous compared to the same crystalline composition. Many emerging pharmaceuticals are practically insoluble in their crystalline forms. Many polymer thermoplastics familiar to everyday use are glasses. For many applications, like glass bottles or eyewear , polymer glasses ( acrylic glass , polycarbonate or polyethylene terephthalate ) are
12052-399: The glass paint away to make the design, or the lettering of an inscription. This was the most common method of making inscriptions in early medieval glass, giving white or light letters on a black background, with later inscriptions more often using black painted letters on a transparent glass background. These are the colours in which the glass itself is made, as opposed to colours applied to
12183-501: The glass some protection against weathering, although this can also be true for paint. They were also probably fired separately, the stain needing a lower heat than the paint. "Sanguine", "carnation", "Rouge Jean Cousin " or "Cousin's rose", after its supposed inventor, is an iron-based fired paint producing red colours, mainly used to highlight small areas, often on flesh. It was introduced around 1500. Copper stain, similar to silver stain but using copper compounds, also produced reds, and
12314-493: The glass transition range. The glass transition may be described as analogous to a second-order phase transition where the intensive thermodynamic variables such as the thermal expansivity and heat capacity are discontinuous. However, the equilibrium theory of phase transformations does not hold for glass, and hence the glass transition cannot be classed as one of the classical equilibrium phase transformations in solids. Glass can form naturally from volcanic magma. Obsidian
12445-406: The glass transition temperature is not supported by empirical research or theoretical analysis (see viscosity in solids ). Though atomic motion at glass surfaces can be observed, and viscosity on the order of 10 –10 Pa s can be measured in glass, such a high value reinforces the fact that glass would not change shape appreciably over even large periods of time. For melt quenching, if the cooling
12576-481: The glass. Ordinary soda-lime glass appears colourless to the naked eye when it is thin, although iron oxide impurities produce a green tint which becomes evident in thick pieces or with the aid of scientific instruments. A number of additives are used to reduce the green tint, particularly if the glass is to be used for plain window glass, rather than stained glass windows. These additives include manganese dioxide which produces sodium permanganate , and may result in
12707-586: The incoming sunlight in the hot and semi-arid climate. Stained glass, as an art form, reached its height in the Middle Ages when it became a major pictorial form used to illustrate the narratives of the Bible to a largely illiterate populace. In the Romanesque and Early Gothic period, from about 950 to 1240, the untraceried windows demanded large expanses of glass which of necessity were supported by robust iron frames, such as may be seen at Chartres Cathedral and at
12838-425: 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 very high temperature to melt, something not all glass factories were able to achieve. Such materials as potash , soda , and lead can be added to lower the melting temperature. Other substances, such as lime , are added to make the glass more stable. Glass
12969-458: The liquid can easily be supercooled into a glass. Examples include LiCl: R H 2 O (a solution of lithium chloride salt and water molecules) in the composition range 4< R <8. sugar glass , or Ca 0.4 K 0.6 (NO 3 ) 1.4 . Glass electrolytes in the form of Ba-doped Li-glass and Ba-doped Na-glass have been proposed as solutions to problems identified with organic liquid electrolytes used in modern lithium-ion battery cells. Following
13100-464: The lofty verticals of Gothic cathedrals and parish churches, glass designs became more daring. The circular form, or rose window , developed in France from relatively simple windows with openings pierced through slabs of thin stone to wheel windows, as exemplified by the west front of Chartres Cathedral, and ultimately to designs of enormous complexity, the tracery being drafted from hundreds of different points, such as those at Sainte-Chapelle , Paris and
13231-424: The major form of medieval 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 even 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 abstract or figurative; may incorporate narratives drawn from
13362-611: The material, e.g. "glass" , " glasses ", " magnifying glass ". Glass is most often formed by rapid cooling ( quenching ) of the molten form. Some glasses such as volcanic glass are naturally occurring, and obsidian has been used to make arrowheads and knives since the Stone Age . Archaeological evidence suggests glassmaking dates back to at least 3600 BC in Mesopotamia , Egypt , or Syria . The earliest known glass objects were beads , perhaps created accidentally during metalworking or
13493-488: The medieval period the glass was abraded; later, hydrofluoric acid was used to remove the flash in a chemical reaction (a very dangerous technique), and in the 19th century sandblasting started to be used for this purpose. There are a number of glass factories, notably in Germany, the United States, England, France, Poland and Russia, which produce high-quality glass, both hand-blown (cylinder, muff, crown) and rolled (cathedral and opalescent). Modern stained-glass artists have
13624-481: The melt whilst it floats on a gas stream) or splat quenching (pressing the melt between two metal anvils or rollers), may be used to increase the cooling rate or to reduce crystal nucleation triggers. In the past, small batches of amorphous metals with high surface area configurations (ribbons, wires, films, etc.) have been produced through the implementation of extremely rapid rates of cooling. Amorphous metal wires have been produced by sputtering molten metal onto
13755-433: The melt. The high density of lead glass (silica + lead oxide (PbO) + potassium oxide (K 2 O) + soda (Na 2 O) + zinc oxide (ZnO) + alumina) results in a high electron density, and hence high refractive index, making the look of glassware more brilliant and causing noticeably more specular reflection and increased optical dispersion . Lead glass has a high elasticity, making the glassware more workable and giving rise to
13886-619: The melting temperature and simplify glass processing. Sodium carbonate (Na 2 CO 3 , "soda") is a common additive and acts to lower the glass-transition temperature. However, sodium silicate is water-soluble , so lime (CaO, calcium oxide , generally obtained from limestone ), along with magnesium oxide (MgO), and aluminium oxide (Al 2 O 3 ), are commonly added to improve chemical durability. Soda–lime glasses (Na 2 O) + lime (CaO) + magnesia (MgO) + alumina (Al 2 O 3 ) account for over 75% of manufactured glass, containing about 70 to 74% silica by weight. Soda–lime–silicate glass
14017-410: The metallic ions will absorb wavelengths of light corresponding to specific colours. In the manufacturing process, glasses can be poured, formed, extruded and moulded into forms ranging from flat sheets to highly intricate shapes. The finished product is brittle but can be laminated or tempered to enhance durability. Glass is typically inert, resistant to chemical attack, and can mostly withstand
14148-409: The most significant architectural innovations of modern times, where glass buildings now often dominate the skylines of many modern cities . These systems use stainless steel fittings countersunk into recesses in the corners of the glass panels allowing strengthened panes to appear unsupported creating a flush exterior. Structural glazing systems have their roots in iron and glass conservatories of
14279-422: The nineteenth century Crown glass (window) Crown glass was an early type of window glass. In this process, glass was blown into a "crown" or hollow globe. This was then transferred from the blowpipe to a punty and then flattened by reheating and spinning out the bowl-shaped piece of glass (bullion) into a flat disk by centrifugal force , up to 5 or 6 feet (1.5 to 1.8 metres) in diameter. The glass
14410-462: The process. The centre 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 also has the pontil mark , a 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
14541-922: The production of faience , which is a form of pottery using lead glazes. Due to its ease of formability into any shape, glass has been traditionally used for vessels, such as bowls , vases , bottles , jars and drinking glasses. Soda–lime glass , containing around 70% silica , accounts for around 90% of modern manufactured glass. Glass can be coloured by adding metal salts or painted and printed with vitreous enamels , leading to its use in stained glass windows and other glass art objects. The refractive , reflective and transmission properties of glass make glass suitable for manufacturing optical lenses , prisms , and optoelectronics materials. Extruded glass fibres have applications as optical fibres in communications networks, thermal insulating material when matted as glass wool to trap air, or in glass-fibre reinforced plastic ( fibreglass ). The standard definition of
14672-476: The production of a window is to make, or acquire from the architect or owners of the building, an accurate template of the window opening that the glass is to fit. The subject matter of the window is determined to suit the location, a particular theme, or the wishes of the patron. A small design called a Vidimus (from Latin "we have seen") is prepared which can be shown to the patron. A scaled model maquette may also be provided. The designer must take into account
14803-400: The push and pull of typical wind loads. However, in the creation of red glass, the colouring ingredients must be of a certain concentration, or the colour will not develop. This results in a colour so intense that at the thickness of 1 / 8 inch (3 mm), the red glass transmits little light and appears black. The method employed to create red stained glass is to laminate
14934-524: The same window. The French Revolution brought about the neglect or destruction of many windows in France. Nonetheless, the country still holds the largest set of Renaissance stained glass in its churches, particularly in the regions of Normandy and Champagne where there were vivid ateliers in many cities until the early 17th century with the stained glass painter Linard Gonthier being active in Troyes until 1642 . There are 1042 preserved 16th-century windows in
15065-424: The selection of the raw materials, e.g., sodium selenite may be preferred over easily evaporating selenium dioxide (SeO 2 ). Also, more readily reacting raw materials may be preferred over relatively inert ones, such as aluminium hydroxide (Al(OH) 3 ) over alumina (Al 2 O 3 ). Usually, the melts are carried out in platinum crucibles to reduce contamination from the crucible material. Glass homogeneity
15196-509: The skilful cutting of coloured glass into sections. Scenes were painted onto glass panels of square format, like tiles. The colours were then annealed to the glass before the pieces were assembled. A method used for embellishment and gilding is the decoration of one side of each of two pieces of thin glass, which are then placed back to back within the lead came . This allows for the use of techniques such as Angel gilding and Eglomise to produce an effect visible from both sides but not exposing
15327-587: The start of the 20th century. By the 17th century, glass in the Venetian tradition was also being produced in England . In about 1675, George Ravenscroft invented lead crystal glass, with cut glass becoming fashionable in the 18th century. Ornamental glass objects became an important art medium during the Art Nouveau period in the late 19th century. Throughout the 20th century, new mass production techniques led to
15458-469: The strength of glass. Carefully drawn flawless glass fibres can be produced with a strength of up to 11.5 gigapascals (1,670,000 psi). The observation that old windows are sometimes found to be thicker at the bottom than at the top is often offered as supporting evidence for the view that glass flows over a timescale of centuries, the assumption being that the glass has exhibited the liquid property of flowing from one shape to another. This assumption
15589-406: The surface of glass, and then fired in a furnace or kiln. They can produce a range of colours from orange -red to yellow. Used on blue glass they produce greens. The way the glass is heated and cooled can significantly affect the colours produced by these compounds. The chemistry involved is complex and not well understood. The chemicals actually penetrate the glass they are added to a little way, and
15720-460: The system Al-Fe-Si may undergo a first-order transition to an amorphous form (dubbed "q-glass") on rapid cooling from the melt. Transmission electron microscopy (TEM) images indicate that q-glass nucleates from the melt as discrete particles with uniform spherical growth in all directions. While x-ray diffraction reveals the isotropic nature of q-glass, a nucleation barrier exists implying an interfacial discontinuity (or internal surface) between
15851-417: The technique therefore gives extremely stable results. By the 15th century it had become cheaper than using pot metal glass and was often used with glass paint as the only colour on transparent glass. Silver stain was applied to the opposite face of the glass to silver paint, as the two techniques did not work well one on top of the other. The stain was usually on the exterior face, where it appears to have given
15982-589: The types used in the traditional fabrication of stained-glass windows. Crown glass is hand-blown glass created by blowing a bubble of air into a gather of molten glass and then spinning it, either by hand or on a table that revolves rapidly like a potter's wheel . The centrifugal force causes the molten bubble to open up and flatten. It can then 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
16113-451: The widespread availability of glass in much larger amounts, making it practical as a building material and enabling new applications of glass. In the 1920s a mould -etch process was developed, in which art was etched directly into the mould so that each cast piece emerged from the mould with the image already on the surface of the glass. This reduced manufacturing costs and, combined with a wider use of coloured glass, led to cheap glassware in
16244-459: The work of famous engravers such as Albrecht Dürer . Original designs often imitate this style. Much 19th-century German glass has large sections of painted detail rather than outlines and details dependent on the lead. The Royal Bavarian Glass Painting Studio was founded by Ludwig I in 1827. A major firm was Mayer of Munich , which commenced glass production in 1860, and is still operating as Franz Mayer of Munich, Inc. . German stained glass found
16375-402: The year 1268. The study found that the room temperature viscosity of this glass was roughly 10 Pa · s which is about 10 times less viscous than a previous estimate made in 1998, which focused on soda-lime silicate glass. Even with this lower viscosity, the study authors calculated that the maximum flow rate of medieval glass is 1 nm per billion years, making it impossible to observe in
16506-619: Was also favoured for large, usually painted, windows of the Baroque period. Coloured glass has been produced since ancient times. Both the Egyptians and the Romans excelled at the manufacture of small colored glass objects. Phoenicia was important in glass manufacture with its chief centres Sidon , Tyre and Antioch . The British Museum holds two of the finest Roman pieces, the Lycurgus Cup , which
16637-475: Was mainly used in the 18th and 19th centuries. "Cold paint" is various types of paint that were applied without firing. Contrary to the optimistic claims of the 12th century writer Theophilus Presbyter , cold paint is not very durable, and very little medieval paint has survived. As well as painting, scratched sgraffito techniques were often used. This involved painting a colour over pot metal glass of another colour, and then before firing selectively scratching
16768-510: Was originally used in the United Kingdom and United States during World War II to manufacture radomes . Uses of fibreglass include building and construction materials, boat hulls, car body parts, and aerospace composite materials. Glass-fibre wool is an excellent thermal and sound insulation material, commonly used in buildings (e.g. attic and cavity wall insulation ), and plumbing (e.g. pipe insulation ), and soundproofing . It
16899-462: Was perfected by French glassmakers in the 1320s, notably around Rouen , and was a trade secret. Hence crown glass was not made in London until 1678. Crown glass is one of many types of hand-blown glass. Other methods include: broad sheet , blown plate , polished plate and cylinder blown sheet . These methods of manufacture lasted at least until the end of the 19th century. The early 20th century marks
17030-539: Was rarely transparent and often contained impurities and imperfections, and is technically faience rather than true glass, which did not appear until the 15th century BC. However, red-orange glass beads excavated from the Indus Valley Civilization dated before 1700 BC (possibly as early as 1900 BC) predate sustained glass production, which appeared around 1600 BC in Mesopotamia and 1500 BC in Egypt. During
17161-450: Was then cut to the size required. The thinnest glass was in a band at the edge of the disk, with the glass becoming thicker and more opaque toward the center. Known as a bullseye , the thicker center area around the pontil mark was used for less expensive windows. To fill large window spaces with the best glass, many small diamond shapes were cut from the edge of the disk, and then some might be halved into triangles. These were mounted in
#869130