Charcoal
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Charcoal
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Charcoal. - PowerPoint PPT Presentation
Transcript of Charcoal
Charcoal
• Charcoal is a black substance that resembles coal and is used as a source of fuel. Charcoal is generally made from wood that has been burnt, or charred, while being deprived of oxygen so that what's left is an impure carbon residue. While charcoal is used in the manufacture of various objects from crayons to filters, its most common use is as a fuel.
How is Charcoal Made?
• To make charcoal, wood or wood scraps are put in either a kiln or dryers to suck out moisture so they’ll bake efficiently, then are typically cooked in cast iron retort ovens.
• These are cylindrically shaped furnaces that work with very little oxygen, so the wood bakes more slowly.
• More oxygen would produce a bigger fire, which would simply incinerate the wood rather than turning it into pure carbon, or wood char.
• The early origins of charcoal based drawings are found in the caves of Lascaux, France. Inscribed onto the walls are primitive drawings of bulls and horses that are believed to be drawn with branches and sticks burnt at the end.
• These paintings are estimated to be 16,000 years old
• The cave was discovered on September 12, 1940
• The cave contains nearly 2,000 figures• Many are too faint to discern, while others
have deteriorated• Over 900 can be identified as animals, and 605
of these have been precisely identified
• Public access was made easier after World War II. By 1955, the carbon dioxide produced by 1,200 visitors per day had visibly damaged the paintings.
• The cave was closed to the public in 1963 in order to preserve the art.
• After the cave was closed, the paintings were restored to their original state, and are now monitored on a daily basis.
• Replica was opened in 1983, 200 meters from the original.
• Since the year 2000 the cave has been beset with a fungus, variously blamed on a new air conditioning system that was installed in the caves, the use of high-powered lights, and the presence of too many visitors.
• As of 2008, the cave contained black mold which scientists are trying to keep away from the paintings.
• In January 2008, authorities closed the cave for three months even to scientists and preservationists. A single individual was allowed to enter the cave for 20 minutes once a week to monitor climatic conditions.
• Now only a few scientific experts are allowed to work inside the cave and just for a few days a month.
• During the Early and Middle Renaissance periods, many artists used charcoal drawing for study and exercises. Charcoal tends to "float" away from the grooves found on canvases, which give artists the ability to freely draw their pieces and easily make corrections. As a result, charcoal drawings were intended as a preliminary sketching tool.
• Charcoal is the oldest are medium known
• Charcoal is used in art for drawing, making rough sketches in painting . Drawing it must usually be preserved by the application of a fixative. Artists generally utilize charcoal in three forms:
• Vine charcoal is created by burning sticks of wood (usually willow) into soft, medium, and hard consistencies.
• Compressed charcoal charcoal powder mixed with gum binder compressed into round or square sticks. The amount of binder determines the hardness of the stick. Compressed charcoal is used in charcoal pencils.
• Powdered charcoal is often used to "tone" or cover large sections of a drawing surface. Drawing over the toned areas will darken it further, but the artist can also lighten (or completely erase) within the toned area to create lighter tones.
• http://gallery.sjsu.edu/arth198/painting/charcoal.html
