Thursday, July 11, 2013

Oil painting

Oil painting is the process of oil paintings with pigments that are bound with a medium of drying oil ??? especially in early modern Europe, linseed oil. Often an oil such as linseed was boiled with a resin such as pine resin or even frankincense; these were called 'varnishes' and were prized for their body and gloss. Other oils occasionally used include poppyseed oil, walnut oil, and safflower oil. These oils confer various properties to the oil paint, such as less yellowing or different drying times. Certain differences are also visible in the sheen of the paints depending on the oil. Painters often use different oils in the same painting depending on specific pigments and effects desired. The paints themselves also develop a particular consistency depending on the medium. Although oil paint was first used for the Buddhist Paintings by Indian and Chinese painters in western Afghanistan sometime between the fifth and ninth centuries, it did not gain popularity until the 15th century. Its practice may have migrated westward during the Middle Ages.

 Canvas Paintings eventually became the principal medium used for creating artworks as its advantages became widely known. The transition began with Early Netherlandish painting in northern Europe, and by the height of the Renaissance oil painting techniques had almost completely replaced tempera paints in the majority of Europe. Techniques Traditional oil painting techniques often begin with the artist sketching the subject onto the canvas with charcoal or thinned paint. Oil paint is usually mixed with linseed oil, artist grade mineral spirits or other solvents to create a thinner, faster or slower drying paint. A basic rule of oil paint application is 'fat over lean.' This means that each additional layer of paint should contain more oil than the layer below to allow proper drying. If each additional layer contains less oil, the final painting will crack and peel. There are many other media that can be used in oil painting, including cold wax, resins, and varnishes. These additional media can aid the painter in adjusting the translucency of the paint, the sheen of the paint, the density or 'body' of the paint, and the ability of the paint to hold or conceal the brushstroke. These variables are closely related to the expressive capacity of oil paint. Traditionally, paint was transferred to the painting surface using paint brushes, but there are other methods, including using palette knives and rags. Oil paint remains wet longer than many other types of artists' materials, enabling the artist to change the color, texture or form of the figure. At times, the painter might even remove an entire layer of paint and begin anew.

This can be done with Art for sale a rag and some turpentine for a certain time while the paint is wet, but after a while, the hardened layer must be scraped. Oil paint dries by oxidation, not evaporation, and is usually dry to the touch within a span of two weeks. It is generally dry enough to be varnished in six months to a year. Art conservators do not consider an oil painting completely dry until it is 60 to 80 years old History Although the history of tempera and related media in Europe indicates that oil painting was discovered there independently, there is evidence that oil painting was used earlier in Afghanistan.[1][2][3][4]Surfaces like shields ??? both those used in tournaments and those hung as decorations ??? were more durable when painted in oil-based media than when painted in the traditional tempera paints. Most Renaissance sources, in particular Vasari, credited northern European painters of the 15th century, and Jan van Eyck in particular, with the "invention" of painting with oil media on wood panel, however Theophilus (Roger of Helmarshausen?) clearly gives instructions for oil-based painting in his treatise, On Various Arts, written in 1125. At this period it was probably used for painting sculptures, carvings and wood fittings, perhaps especially for outdoor use. Early Netherlandish painting in the 15th century was however the first to make oil the usual painting medium, and explore the use of layers and glazes, followed by the rest of Northern Europe, and only then Italy. Early works were still panel paintings on wood, but around the end of the 15th century canvas became more popular, as it was cheaper, easier to transport, and allowed larger works. Venice, where sail-canvas was easily available, led the move. The popularity of oil spread through Italy from the North, starting in Venice in the late 15th century. By 1540 the previous method for painting on panel, tempera had become all but extinct, although Italians continued to use fresco for wall paintings, which was more difficult in Northern climates. Ingredients The linseed oil itself comes from the flax seed, a common fiber crop. It is interesting to note that linen, an important "support" for oil painting (see below) also comes from the flax plant. Safflower oil is sometimes used in formulating lighter colors such as white because it "yellows" less on drying than does linseed oil, but it has the slight drawback of drying more slowly. Recent advances in chemistry have produced modern water miscible oil paints that can be used with and cleaned up with water. Small alterations in the molecular structure of the oil creates this water miscible property. A still-newer type of paint,Canvas Art heat-set oils, remain liquid until heated to 265???280 F (130???138 C) for about 15 minutes. Since the paint never dries otherwise, cleanup is not needed (except when one wants to use a different color and the same brush). Although not technically true oils (the medium is an unidentified "non-drying synthetic oily liquid, imbedded with a heat sensitive curing agent"), the paintings resemble oil paintings and are usually shown as oil paintings. Traditional artists' canvas is made from linen, but less expensive cotton fabric has gained popularity. The artist first prepares a wooden frame called a "stretcher" or "strainer".

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