Mosaic

From Free net encyclopedia

This article is about a decorative art. See Mosaic (disambiguation) for other meanings.

Image:Mosaic.woodchester.arp.750pix.jpg

Mosaic is the art of decoration with small pieces of colored glass, stone or other material. It may be a technique of decorative art, an aspect of interior decoration or of cultural significance as in a cathedral. Small tiles or fragments of pottery (known as tesserae, diminutive tessellae) or of colored glass or clear glass backed with metal foils, are used to create a pattern or picture.

1 Use
2 Mosaic technique
3 Mathematics
4 Digital imaging
5 External links

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Use

Mosaic was used across the ancient world for domestic interior decoration. Mosaics of the 4th century BC are found in the Macedonian palace-city of Aegina and they enriched the floors of Hellenistic villas, but mosaic floors are particularly associated with Roman dwellings, from Britain to Dura-Europas. Splendid mosaic floors distinguished luxurious Roman villas across north Africa. In Rome, Nero and his architects used mosaics to cover the surfaces of wall and ceilings in the Domus Aurea, built 64 CE.

With the building of Christian basilicas in the late 4th century, wall and ceiling mosaics were adapted to Christian uses. The greatest development of Christian mosaics unfolded in the Byzantine empire including its outpost the Exarchate of Ravenna and its territories in Sicily, and in its rival Venice, where mosaic encrusts the exterior and interior of St Mark's. In Western Europe, the demanding techniques of fresco replaced the even more labor-intensive techniques of mosaic.

Islamic architecture used mosaic technique in intricate geometric designs. The process is known as zillij in North Africa and qashani further east. Some of the best examples of Islamic mosaics were produced in Moorish Spain and are still visible at the Alhambra. The craft has also been popular in the Eastern Orthodox tradition and in Russia.

A modern example of mosaic is the Museum of Natural History station of the New York Subway.

Some spectacular modern mosaics are the work of modernisme style architects Antoni Gaudí and Josep Maria Jujol, for example the unique mosaics in the Park Güell in Barcelona. Ravenna (Italy) is known world-wide as the Capital of Mosaic on account of its unique artistic heritage. A few miles from Venice and Florence, Ravenna means a fantastic tour to discover a city rich of artistic treasures such as S. Apollinare Nuovo, Basilica di San Vitale, Mausoleo di Galla Placidia.

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Mosaic technique

There are three main methods - the direct method, the indirect method and the double indirect method.

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Direct method

The direct method of mosaic construction involves directly placing (gluing) the individual tesserae onto the supporting surface. This method is well suited to surfaces which have a three dimensional quality such as vases.

The direct method suits small projects which are transportable. Another advantage of the direct method is that the resulting mosaic is progressively visible allowing for any adjustments to tile placing or colors to.

The disadvantage of the direct method is that the artist must work directly at the chosen surface which is often not practical for long periods of time. It is unsuitable for large scale projects. Also, it is difficult to control the evenness of the finished surface. This is of particular importance when creating a functional surface such as a floor or a table top.

A modern version of the direct method, sometimes called "Double Direct" is to work direct onto fiberglass mesh. The mosaic can then be constructed the right way up and then transported to its final place. Large work can be done in this way, with the mosaic being cut up for shipping and then put back together for installation. It enables the artist to work in comfort in a studio rather than at the site of installation. South African mosaic artist Stevie Godson is widely acclaimed for her works using this method.

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Indirect method

The indirect method of applying tesserae is often used for very large projects with repetitive elements. Tiles are applied upside down to an adhesive backing paper, and later transferred onto walls, floors or craft projects. This method is most useful for mosaics with simple or geometric patterns, solid blocks of color, and extremely large projects. Mosaic tabletops are usually made using the indirect method, as it results in a smoother and more even surface.

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Double indirect method

The double indirect method is often used when it is important to see the work during the creation process as it will appear when completed. The tesserae are placed face-up on a medium (often adhesive-backed paper or sticky plastic) as it will appear when installed. When the mosaic is complete, a similar medium is placed atop it. The piece is then turned over, the original underlaying material is removed, and the piece is installed as in the indirect method described above.

Both indirect and double-indirect methods are often performed in sections, allowing extremely large projects such as murals to be completed off-site and transported to their destination without large trucks being needed.

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Mathematics

The best way to arrange various shaped tiles on a surface can lead to complicated mathematical problems - see tessellation for details. Roger Penrose is a mathematician who has worked with tiling problems - see Penrose tilings.

The artist M.C. Escher was influenced by Moorish mosaics to begin his investigations into tessellation.

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Digital imaging

A mosaic in digital imaging is a plurality of non-overlapping images, arranged in some tessellation. A photomosaic is a picture made up of various other pictures (pioneered by Joseph Francis), in which each "pixel" is actually another picture, when examined closely.

A tile mosaic is a digital image made up of individual tiles, arranged in a non-overlapping fashion, e.g. to make a static image on a shower room or bathing pool floor, by breaking the image down into square pixels formed from ceramic tiles (a typical size is 1 inch by 1 inch, as for example, on the floor of the University of Toronto pool, though sometimes larger tiles such as 2 by 2 inch are used). These digital images are coarse in resolution, and often simply express text, such as the depth of the pool in various places, but some such digital images are used to show a sunset, or other beach theme. Obviously digital images expressed in ceramic tile are of very low resolution.

Thus apart from the artistic value (i.e. the work of Robert Silvers, and others who use mosaicing creatively), the mosaicing is usually considered an artifact to be filtered out, through interpolation by demosaicing.

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