Editing Mirror (section)

== History ==
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| image1 = Egypt, New Kingdom, Dynasty 18 - Caryatid Mirror - 1983.196 - Cleveland Museum of Art.tif
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| image2 = NAMA Femme au miroir.jpg
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| footer = '''Left:''' Bronze mirror, [[New Kingdom of Egypt]], [[Eighteenth dynasty of Egypt|Eighteenth Dynasty]], 1540–1296 BC, [[Cleveland Museum of Art]] (U.S.)<br />'''Right:''' seated woman holding a mirror; [[Ancient Greece|Ancient Greek]] Attic [[Red-figure pottery|red-figure]] [[lekythos]] by the [[Sabouroff Painter]], c. 470–460 BC, [[National Archaeological Museum, Athens]] (Greece)
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[[File:Naples National Archaeological Museum (14842094122).jpg|thumb|[[Roman art|Roman fresco]] of a woman fixing her hair using a mirror, from [[Stabiae]], Italy, 1st century AD]]
[[File:The Arnolfini Portrait, détail (2).jpg|thumb|Detail of the convex mirror from the [[Arnolfini portrait]], [[Bruges]], 1434 AD]]
[[File:Histoire de femme Gu Kai Zhi.jpg|thumb|'Adorning Oneself', detail from 'Admonitions of the Instructress to the Palace Ladies', [[Tang dynasty]] copy of an original by [[Chinese painting|Chinese painter]] [[Gu Kaizhi]], {{Circa|344–405 AD}}]]
[[File:Lady looking into mirror Belur Halebidu.jpg|thumb|A sculpture of a lady looking into a mirror, from [[Halebidu]], India, in the 12th century]]

===Prehistory===
The first mirrors used by humans were most likely pools of still water, or shiny stones.<ref>{{Cite book |last1=Melchior-Bonnet |first1=Sabine |title=The mirror: a history |last2=Jewett |first2=Katharina H. |last3=Delumeau |first3=Jean |date=2001 |publisher=Routledge |isbn=978-0-415-92447-4 |location=New York London}}</ref> The requirements for making a good mirror are a surface with a very high degree of [[Flat space|flatness]] (preferably but not necessarily with high [[reflectivity]]), and a [[surface roughness]] smaller than the wavelength of the light.

The earliest manufactured mirrors were pieces of polished stone such as [[obsidian]], a naturally occurring [[volcanic glass]].<ref name=fior2009/> Examples of obsidian mirrors found at [[Çatalhöyük]] in [[Anatolia]] (modern-day Turkey) have been dated to around 6000&nbsp;BCE.<ref name=enoch/> Mirrors of polished copper were crafted in [[Mesopotamia]] from 4000&nbsp;BCE,<ref name=enoch/> and in ancient Egypt from around 3000&nbsp;BCE.<ref name=stoc/> Polished stone mirrors from Central and South America date from around 2000&nbsp;BCE onwards.<ref name=enoch/>

===Bronze Age to Early Middle Ages===
{{main|Bronze mirror}}
By the [[Bronze Age]] most cultures were using mirrors made from polished discs of [[bronze]], [[copper]], [[silver]], or other metals.<ref name=fior2009/><ref name=whit2013/> The people of [[Kerma culture|Kerma]] in [[Nubia]] were skilled in the manufacturing of mirrors. Remains of their bronze [[kiln]]s have been found within the temple of Kerma.<ref>{{cite book| last = Bianchi| first = Robert Steven| title = Daily Life of the Nubians| year = 2004| publisher = Greenwood Publishing Group| isbn = 978-0-313-32501-4| page = 81 }}</ref> In China, [[bronze mirror]]s were manufactured from around 2000&nbsp;BC,<ref name="Ancient Chinese Bronze Mirrors">{{cite web |title=Ancient Chinese Bronze Mirrors |url=https://www.huntington.org/ancient-chinese-bronze-mirrors |website=The Huntington |publisher=The Huntington Library, Art Museum and Gardens |access-date=15 November 2020 |archive-date=17 November 2020 |archive-url=https://web.archive.org/web/20201117031015/https://www.huntington.org/ancient-chinese-bronze-mirrors |url-status=live }}</ref> some of the earliest bronze and copper examples being produced by the [[Qijia culture]]. Such metal mirrors remained the norm through to [[Greco-Roman]] Antiquity and throughout the [[Middle Ages]] in [[Europe]].<ref name=brit2009/> During the [[Roman Empire]] silver mirrors were in wide use by servants.<ref name=roma2019/>

[[Speculum metal]] is a highly reflective [[alloy]] of copper and [[tin]] that was used for mirrors until a couple of centuries ago.{{when|date=August 2022}}{{vague|date=August 2022}} Such mirrors may have originated in China and India.<ref name=need1974/> Mirrors of speculum metal or any precious metal were hard to produce and were only owned by the wealthy.<ref name=hopk1910/>

Common metal mirrors tarnished and required frequent polishing. Bronze mirrors had low reflectivity and poor [[color rendering]], and stone mirrors were much worse in this regard.<ref name=bonn2011/>{{rp|p.11}} These defects explain the [[New Testament]] reference in [[1 Corinthians 13]] to seeing "as in a mirror, darkly."

The [[Ancient Greece|Greek]] [[philosopher]] [[Socrates]] urged young people to look at themselves in mirrors so that, if they were beautiful, they would become worthy of their beauty, and if they were ugly, they would know how to hide their disgrace through learning.<ref name=bonn2011/>{{rp|p.106}}

[[Glass]] began to be used for mirrors in the 1st century [[Common Era|CE]], with the development of [[soda-lime glass]] and [[glass blowing]].<ref name=pulk1999/> The Roman scholar [[Pliny the Elder]] claims that artisans in [[Sidon]] (modern-day [[Lebanon]]) were producing glass mirrors coated with [[lead]] or [[gold leaf]] in the back. The metal provided good reflectivity, and the glass provided a smooth surface and protected the metal from scratches and tarnishing.<ref name=plin0077/><ref name=holl2009/><ref name=ande2008/><ref name=bonn2011/>{{rp|p.12}}<ref name=kels2007/> However, there is no archeological evidence of glass mirrors before the third century.<ref name=degy/>

These early glass mirrors were made by blowing a glass bubble, and then cutting off a small circular section from 10 to 20 [[centimetre|cm]] in diameter. Their surface was either concave or convex, and imperfections tended to distort the image. Lead-coated mirrors were very thin to prevent cracking by the heat of the molten metal.<ref name=bonn2011/>{{rp|p.10}} Due to the poor quality, high cost, and small size of glass mirrors, solid-metal mirrors (primarily of steel) remained in common use until the late nineteenth century.<ref name=bonn2011/>{{rp|p.13}}

Silver-coated metal mirrors were developed in China as early as 500 CE. The bare metal was coated with an [[amalgam (chemistry)|amalgam]], then heated until the [[mercury (element)|mercury]] boiled away.<ref name=rapp2009/>

===Middle Ages and Renaissance===
[[File:Johann Jacob Kirstein 001.JPG|thumb|An 18th century [[vermeil]] mirror in the [[Musée des Arts décoratifs, Strasbourg]]]]
[[File:Mirror with laquered back inlaid with 4 phoenixes holding ribbons in their mouths. Tang Dynasty. Eastern Xi'an city.jpg|thumb|A mirror with lacquered back inlaid with four phoenixes holding ribbons in their mouths during the [[Tang dynasty]] in eastern [[Xi'an]]]]
The evolution of glass mirrors in the [[Middle Ages]] followed improvements in [[glassmaking]] technology. Glassmakers in [[France]] made flat glass plates by blowing glass bubbles, spinning them rapidly to flatten them, and cutting rectangles out of them. A better method, developed in [[Germany]] and perfected in [[Venice]] by the 16th century, was to blow a cylinder of glass, cut off the ends, slice it along its length, and unroll it onto a flat hot plate.<ref name=bonn2011/>{{rp|p.11}} Venetian glassmakers also adopted [[lead glass]] for mirrors, because of its crystal-clarity and its easier workability.

During the early European [[Renaissance]], a [[gilding#Fire-gilding|fire-gilding]] technique developed to produce an even and highly reflective [[tin]] coating for glass mirrors. The back of the glass was coated with a tin-mercury amalgam, and the mercury was then evaporated by heating the piece. This process caused less [[thermal shock]] to the glass than the older molten-lead method.<ref name=bonn2011/>{{rp|p.16}} The date and location of the discovery is unknown, but by the 16th century Venice was a center of mirror production using this technique. These Venetian mirrors were up to {{convert|40|in|cm}} square.

For a century, Venice retained the monopoly of the tin amalgam technique. Venetian mirrors in richly decorated frames served as luxury decorations for palaces throughout Europe, and were very expensive. For example, in the late seventeenth century, the Countess de Fiesque was reported to have traded an entire wheat farm for a mirror, considering it a bargain.<ref name=hads1993/> However, by the end of that century the secret was leaked through industrial espionage. French workshops succeeded in large-scale industrialization of the process, eventually making mirrors affordable to the masses, in spite of the [[toxicity]] of mercury's vapor.<ref name=iriw2018/>

===Industrial Revolution===
{{Further|Industrial Revolution}}
The invention of the [[History of glass#Industrial production|ribbon machine]] in the late [[Industrial Revolution]] allowed modern glass panes to be produced in bulk.<ref name=bonn2011/> The [[Saint-Gobain]] factory, founded by royal initiative in France, was an important manufacturer, and [[Bohemia]]n and German glass, often rather cheaper, was also important.

The invention of the [[silvering|silvered-glass]] mirror is credited to German chemist [[Justus von Liebig]] in 1835.<ref name=lieb185/> His [[Silvering#Silver|wet deposition]] process involved the deposition of a thin layer of metallic silver onto glass through the chemical reduction of [[silver nitrate]]. This silvering process was adapted for mass manufacturing and led to the greater availability of affordable mirrors.

===Contemporary technologies===
Mirrors are often produced by the wet deposition of silver, or sometimes nickel or chromium (the latter used most often in automotive mirrors) via [[electroplating]] directly onto the glass substrate.<ref name=mlink2014/>

Glass mirrors for optical instruments are usually produced by [[vacuum deposition]] methods. These techniques can be traced to observations in the 1920s and 1930s that metal was being ejected from [[electrode]]s in [[gas discharge lamp]]s and condensed on the glass walls forming a mirror-like coating. The phenomenon, called [[sputtering]], was developed into an industrial metal-coating method with the development of [[semiconductor]] technology in the 1970s.

A similar phenomenon had been observed with [[incandescent light bulbs]]: the metal in the hot filament would slowly [[sublimation (phase transition)|sublimate]] and condense on the bulb's walls. This phenomenon was developed into the method of [[evaporation (deposition)|evaporation coating]] by Pohl and Pringsheim in 1912. [[John D. Strong]] used evaporation coating to make the first [[aluminium]]-coated telescope mirrors in the 1930s.<ref name=matt2004/> The first [[dielectric mirror]] was created in 1937 by Auwarter using evaporated [[rhodium]].<ref name=pulk1999/>

The metal coating of glass mirrors is usually protected from abrasion and corrosion by a layer of paint applied over it. Mirrors for optical instruments often have the metal layer on the front face, so that the light does not have to cross the glass twice. In these mirrors, the metal may be protected by a thin transparent coating of a non-metallic ([[dielectric]]) material. The first metallic mirror to be enhanced with a dielectric coating of [[silicon dioxide]] was created by Hass in 1937. In 1939 at the [[Schott Glass]] company, Walter Geffcken invented the first dielectric mirrors to use multilayer coatings.<ref name=pulk1999/>

===Burning mirrors===
The [[Ancient Greece|Greek]] in [[Classical Antiquity]] were familiar with the use of mirrors to concentrate light. [[Parabolic mirror]]s were described and studied by the mathematician [[Diocles (mathematician)|Diocles]] in his work ''On Burning Mirrors''.<ref name=fried2001/> [[Ptolemy]] conducted a number of experiments with curved polished iron mirrors,<ref name=pend2004/>{{rp|p.64}} and discussed plane, convex spherical, and concave spherical mirrors in his ''Optics''.<ref name=mark1996/>

Parabolic mirrors were also described by the [[Caliphate]] mathematician [[Ibn Sahl (mathematician)|Ibn Sahl]] in the tenth century.<ref name=rash1990/>