Editing Stained glass (section)

===Flashed glass===
Architectural glass must be at least {{sfrac|1|8}} of an inch (3&nbsp;mm) thick to survive 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 {{sfrac|1|8}} inch (3&nbsp;mm), the red glass transmits little light and appears black. The method employed to create red stained glass is to laminate 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 is that the double-layered glass can be engraved or [[Abrasion (mechanical)|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 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.

Islamic civilization played a major role in inspiring the art of stained glass from the 8th century onward. Mosques, homes, and cities were transformed into beautiful spaces decorated with glass. Beauty and function were essential elements of design in Islamic civilization. Perhaps in an effort to supply thousands of mosques, but also thanks to the input provided by thriving scientific activity in fields such as optics and chemistry, Islamic glassmakers transformed what had previously been a craft into Islamic stained glass, an industry employing new technologies and a large workforce from across Islamic civilization.

Across Islamic civilization, glass vessels were mass-produced from the 8th century onwards, either by blowing liquid glass in chambers or by cutting it from crystal. Glassmakers in [[Syria]], and to a lesser extent Egypt, inherited and improved upon this glassmaking technique, developing their own techniques for mastering the art of Islamic stained glass, its coloring, and its decoration, expanding the variety of products.

The history of stained glass in [[Syria]] dates back to ancient times, as [[Syria]] was influenced by successive civilizations, such as the Roman and Byzantine. [[Syrians|Syrian]] stained glass is characterized by its intricate geometric and floral designs, reflecting the skill of Syrian artisans.

There are a number of glass factories, particularly in [[Germany]], the United States, [[England]], [[France]], [[Poland]], [[Russia]], and [[Syria]], which produce high-quality glass, both hand-blown (cylinder, disc, and crown) and rolled (cathedral and opalescent). Contemporary stained glass artists have a number of resources to draw on in their work for centuries from other artists, from whom they learn, continuing the tradition in new ways. In the late 19th and 20th centuries, there were many innovations in techniques and types of glass used. Many new types of glass were developed for use in stained glass windows, notably Tiffany glass and stained glass panels.