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Oil painting is the process of painting with pigments with a medium of drying oil as the binder. Commonly used drying oils include linseed oil, poppy seed oil, walnut oil, and safflower oil. The choice of oil imparts a range of properties to the oil paint, such as the amount of yellowing or drying time. The paint could be thinned with Turpentine. Certain differences, depending on the oil, are also visible in the sheen of the paints. An artist might use several 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. The oil may be boiled with a resin, such as pine resin or frankincense, to create a varnish prized for its body and gloss. The paint itself can be molded into different textures from the plasticity that it contains. Before oil painting was fully discovered egg tempera was commonly used. Tempera did not have the flexibility in pigment that oil paints provided.
The oldest known oil paintings were created by Buddhist artists in Afghanistanand date back to the 7th century AD. The technique of binding pigments in oil eventually made its way to Europe by at least the 12th century. The adoption of oil paint by Europeans began with Early Netherlandish painting in Northern Europe, and by the height of the Renaissance, oil painting techniques had almost completely replaced the use of previously favored tempera paints in the majority of Europe.
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 make the paint thinner, faster or slower-drying. (Because the solvents thin the oil in the paint, they can also be used to clean paint brushes.) A basic rule of oil paint application is 'fat over lean', meaning 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. The consistency on the canvas depend on the layering of the oil paint. This rule does not ensure permanence; it is the quality and type of oil that leads to a strong and stable paint film.
There are other media that can be used with the oil, 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 aspects of the paint are closely related to the expressive capacity of oil paint.
Traditionally, paint was most often transferred to the painting surface using paintbrushes, but there are other methods, including using palette knives and rags. Palette knives can scrape off any paint from a canvas, it can also be used for application. 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 a rag and some turpentine for a time while the paint is wet, but after a while the hardened layer must be scraped off. Oil paint dries by oxidation, not evaporation, and is usually dry to the touch within a span of two weeks (some colors dry within days).
The earliest known surviving oil paintings are Buddhist murals created circa 650AD in Bamiyan, Afghanistan. Bamiyan is an historic settlement along the silk road and is famous for the Bamiyan Buddhas, a series of giant statues, behind which rooms and tunnels are carved from the rock. The murals are located in these rooms. The artworks display a wide range of pigments and ingredients, and even included the use of a final varnish layer. The refinement of this painting technique and the survival of the paintings into the present day suggests that oil paints had been used in Asia for some time before the 7th century.
Most European Renaissance sources, in particular Vasari, falsely credit northern European painters of the 15th century, and Jan van Eyck in particular, with the "invention" of oil paintsHowever, Theophilus (Roger of Helmarshausen?) clearly gives instructions for oil-based painting in his treatise, On Various Arts, written about 1125. At this period, it was probably used for painting sculptures, carvings and wood fittings, perhaps especially for outdoor use. Outdoor surfaces and 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. However, early Netherlandish painting with artists like Van Eyck and Robert Campin in the early and mid-15th century were 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.
Such works were painted on wooden panels, but towards the end of the 15th century canvas began to be used as a support, as it was cheaper, easier to transport, allowed larger works, and did not require complicated preliminary layers of gesso (a fine type of plaster). Venice, where sail-canvas was easily available, was a leader in the move to canvas. Small cabinet paintings were also made on metal, especially copper plates. These supports were more expensive but very firm, allowing intricately fine detail. Often printing plates from printmaking were reused for this purpose. The increasing use of oil spread through Italy from Northern Europe, 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 chalk-based fresco for wall paintings, which was less successful and durable in damper northern climates.
Renaissance techniques used a number of thin almost transparent layers or glazes, usually each allowed to dry before the next was added, greatly increasing the time a painting took. The underpainting or ground beneath these was usually white (typically gesso coated with a primer), allowing light to reflect back through the layers. But van Eyck, and Robert Campin a little later, used a wet-on-wet technique in places, painting a second layer soon after the first. Initially the aim was, as with the established techniques of tempera and fresco, to produce a smooth surface when no attention was drawn to the brushstrokes or texture of the painted surface. Among the earliest impasto effects, using a raised or rough texture in the surface of the paint, are those from the later works of the Venetian painter Giovanni Bellini, around 1500.
This became much more common in the 16th century, as may painters began to draw attention to the process of their painting, by leaving individual brushstrokes obvious, and a rough painted surface. Another Venetian, Titian, was a leader in this. In the 17th century some artists, including Rembrandt, began to use dark grounds. Until the mid-19th century there was a division between artists who exploited "effects of handling" in their paintwork, and those who continued to aim at "an even, glassy surface from which all evidences of manipulation had been banished".
Before the 19th century, artists or their apprentices ground pigments and mixed their paints for the range of painting media. This made portability difficult and kept most painting activities confined to the studio. This changed when tubes of oil paint became widely available following the American portrait painter John Goffe Rand's invention of the squeezable or collapsible metal tube in 1841. Artists could mix colors quickly and easily, which enabled, for the first time, relatively convenient plein air painting (a common approach in French Impressionism)
The linseed oil itself comes from the flax seed, a common fiber crop. Linen, a "support" for oil painting (see relevant section), also comes from the flax plant. Safflower oil or the walnut or poppyseed oil are sometimes used in formulating lighter colors like white because they "yellow" less on drying than linseed oil, but they have the slight drawback of drying more slowly and may not provide the strongest paint film. Linseed oil tends to dry yellow and can change the hue of the color.
Recent advances in chemistry have produced modern water miscible oil paints that can be used and cleaned up with water. Small alterations in the molecular structure of the oil creates this water miscible property.
The earliest oil paintings were almost all panel paintings on wood, which had been seasoned and prepared in a complicated and rather expensive process with the panel constructed from several pieces of wood, although such a support has a tendency to warp. Panels continued to be used well into the 17th century, including by Rubens, who painted several large works on wood. The artists of the Italian regions moved towards canvas in the early 16th century, led partly by a wish to paint larger images, which would have been too heavy as panels. Canvas for sails was made in Venice and so easily available and cheaper than wood.
Smaller paintings, with very fine detail, were easier to paint on a very firm surface, and wood panels or copper plates, often reused from printmaking, were often chosen for small cabinet paintings even in the 19th century. Portrait miniatures normally used very firm supports, including ivory, or stiff paper card.
Traditional artists' canvas is made from linen, but less expensive cotton fabric has been used. The artist first prepares a wooden frame called a "stretcher" or "strainer". The difference between the two names is that stretchers are slightly adjustable, while strainers are rigid and lack adjustable corner notches. The canvas is then pulled across the wooden frame and tacked or stapled tightly to the back edge. Then the artist applies a "size" to isolate the canvas from the acidic qualities of the paint. Traditionally, the canvas was coated with a layer of animal glue (modern painters will use rabbit skin glue) as the size and primed with lead white paint, sometimes with added chalk. Panels were prepared with a gesso, a mixture of glue and chalk.
Modern acrylic "gesso" is made of titanium dioxide with an acrylic binder. It is frequently used on canvas, whereas real gesso is not suitable for canvas. The artist might apply several layers of gesso, sanding each smooth after it has dried. Acrylic gesso is very difficult to sand. One manufacturer makes a "sandable" acrylic gesso, but it is intended for panels only and not canvas. It is possible to make the gesso a particular color, but most store-bought gesso is white. The gesso layer, depending on its thickness, will tend to draw the oil paint into the porous surface. Excessive or uneven gesso layers are sometimes visible in the surface of finished paintings as a change that's not from the paint.
Standard sizes for oil paintings were set in France in the 19th century. The standards were used by most artists, not only the French, as it was—and evidently still is—supported by the main suppliers of artists' materials. Size 0 (toile de 0) to size 120 (toile de 120) is divided in separate "runs" for figures (figure), landscapes (paysage) and marines (marine) that more or less preserve the diagonal. Thus a 0 figure corresponds in height with a paysage 1 and a marine 2.
Although surfaces like linoleum, wooden panel, paper, slate, pressed wood, Masonite, and cardboard have been used, the most popular surface since the 16th century has been canvas, although many artists used panel through the 17th century and beyond. Panel is more expensive, heavier, harder to transport, and prone to warp or split in poor conditions. For fine detail, however, the absolute solidity of a wooden panel has an advantage.
Oil paint is made by mixing pigments of colors with an oil medium. Since the 19th century the different main colors are purchased in paint tubes pre-prepared before painting begins, further shades of color are usually obtained by mixing small quantities together as the painting process is underway. An artist's palette, traditionally a thin wood board held in the hand, is used for holding and mixing paints. Pigments may be any number of natural or synthetic substances with color, such as sulphides for yellow or cobalt salts for blue. Traditional pigments were based on minerals or plants, but many have proven unstable over long periods of time. Modern pigments often use synthetic chemicals. The pigment is mixed with oil, usually linseed, but other oils may be used. The various oils dry differently, which creates assorted effects.
A brush is most commonly employed by the artist to apply the paint, often over a sketched outline of their subject (which could be in another medium). Brushes are made from a variety of fibers to create different effects. For example, brushes made with hog bristle might be used for bolder strokes and impasto textures. Fitch hair and mongoose hair brushes are fine and smooth, and thus answer well for portraits and detail work. Even more expensive are red sable brushes (weasel hair). The finest quality brushes are called "kolinsky sable"; these brush fibers are taken from the tail of the Siberian weasel. This hair keeps a superfine point, has smooth handling, and good memory (it returns to its original point when lifted off the canvas), known to artists as a brush's "snap". Floppy fibers with no snap, such as squirrel hair, are generally not used by oil painters.
In the past few decades, many synthetic brushes have been marketed. These are very durable and can be quite good, as well as cost efficient.
Brushes come in multiple sizes and are used for different purposes. The type of brush also makes a difference. For example, a "round" is a pointed brush used for detail work. "Flat" brushes are used to apply broad swaths of color. "Bright" is a flat brush with shorter brush hairs, used for "scrubbing in". "Filbert" is a flat brush with rounded corners. "Egbert" is a very long, and rare, filbert brush. The artist might also apply paint with a palette knife, which is a flat metal blade. A palette knife may also be used to remove paint from the canvas when necessary. A variety of unconventional tools, such as rags, sponges, and cotton swabs, may be used to apply or remove paint. Some artists even paint with their fingers.
Old masters usually applied paint in layers known as "glazes", a method also simply called "indirect painting". This method was first perfected through an adaptation of the egg tempera painting technique (egg yolks used as a binder, mixed with pigment), and was applied by the Early Netherlandish painters in Northern Europe with pigments usually ground in linseed oil. This approach has been called the "mixed technique" or "mixed method" in modern times. The first coat (the underpainting) is laid down, often painted with egg tempera or turpentine-thinned paint. This layer helps to "tone" the canvas and to cover the white of the gesso. Many artists use this layer to sketch out the composition. This first layer can be adjusted before proceeding further, an advantage over the "cartooning" method used in fresco technique. After this layer dries, the artist might then proceed by painting a "mosaic" of color swatches, working from darkest to lightest. The borders of the colors are blended together when the "mosaic" is completed and then left to dry before applying details.
Artists in later periods, such as the Impressionist era (late 19th century), often expanded on this wet-on-wet method, blending the wet paint on the canvas without following the Renaissance-era approach of layering and glazing. This method is also called "alla prima". This method was created due to the advent of painting outdoors, instead of inside a studio, because while outside, an artist did not have the time to let each layer of paint dry before adding a new layer. Several contemporary artists use a combination of both techniques to add bold color (wet-on-wet) and obtain the depth of layers through glazing.
When the image is finished and has dried for up to a year, an artist often seals the work with a layer of varnish that is typically made from dammar gum crystals dissolved in turpentine. Such varnishes can be removed without disturbing the oil painting itself, to enable cleaning and conservation. Some contemporary artists decide not to varnish their work, preferring the surface unvarnished.
Acrylic paint is a fast-drying paint made of pigment suspended in acrylic polymer emulsion and plasticizers, silicon oils, defoamers, stabilizers, or metal soaps. Most acrylic paints are water-based, but become water-resistant when dry. Depending on how much the paint is diluted with water, or modified with acrylic gels, mediums, or pastes, the finished acrylic painting can resemble a watercolor, a gouache, or an oil painting, or have its own unique characteristics not attainable with other media.
A mural is any piece of artwork painted or applied directly on a wall, ceiling or other permanent surfaces. A distinguishing characteristic of mural painting is that the architectural elements of the given space are harmoniously incorporated into the picture.
Paint is any pigmented liquid, liquefiable, or solid mastic composition that, after application to a substrate in a thin layer, converts to a solid film. It is most commonly used to protect, color, or provide texture to objects. Paint can be made or purchased in many colors—and in many different types, such as watercolor or synthetic. Paint is typically stored, sold, and applied as a liquid, but most types dry into a solid. Most paints are either oil-based or water-based and each have distinct characteristics. For one, it is illegal in most municipalities to discard oil-based paint down household drains or sewers. Clean up solvents are also different for water-based paint than they are for oil-based paint. Water-based paints and oil-based paints will cure differently based on the outside ambient temperature of the object being painted Usually the object being painted must be over 10 °C (50 °F), although some manufacturers of external paints/primers claim they can be applied when temperatures are as low as 2 °C (35 °F).
Tempera, also known as egg tempera, is a permanent, fast-drying painting medium consisting of colored pigments mixed with a water-soluble binder medium, usually glutinous material such as egg yolk. Tempera also refers to the paintings done in this medium. Tempera paintings are very long-lasting, and examples from the first century AD still exist. Egg tempera was a primary method of painting until after 1500 when it was superseded by the invention of oil painting. A paint consisting of pigment and binder commonly used in the United States as poster paint is also often referred to as "tempera paint", although the binders in this paint are different from traditional tempera paint.
Gesso is a white paint mixture consisting of a binder mixed with chalk, gypsum, pigment, or any combination of these. It is used in painting as a preparation for any number of substrates such as wood panels, canvas and sculpture as a base for paint and other materials that are applied over it.
Gouache, body color, or opaque watercolor, is a water-medium, paint consisting of natural pigment, water, a binding agent, and sometimes additional inert material. Gouache is designed to be opaque. Gouache has a considerable history, having been used for at least twelve centuries. It is used most consistently by commercial artists for posters, illustrations, comics, and other design work.
Canvas is an extremely durable plain-woven fabric used for making sails, tents, marquees, backpacks, shelters, as a support for oil painting and for other items for which sturdiness is required, as well as in such fashion objects as handbags, electronic device cases, and shoes. It is also popularly used by artists as a painting surface, typically stretched across a wooden frame.
Oil paint is a type of slow-drying paint that consists of particles of pigment suspended in a drying oil, commonly linseed oil. The viscosity of the paint may be modified by the addition of a solvent such as turpentine or white spirit, and varnish may be added to increase the glossiness of the dried oil paint film. Oil paints were first used in Asia as early as the 7th century AD, and can be seen in examples of Buddhist painting in Afghanistan. Oil based paints made their way to Europe by the 12th century and were used for simple decoration, but did not begin to be adopted as an artistic medium there until the early 15th century. Common modern applications of oil paint are in finishing and protection of wood in buildings and exposed metal structures such as ships and bridges. Its hard-wearing properties and luminous colors make it desirable for both interior and exterior use on wood and metal. Due to its slow-drying properties, it has recently been used in paint-on-glass animation. Thickness of coat has considerable bearing on time required for drying: thin coats of oil paint dry relatively quickly.
Water-miscible oil paint is oil paint either engineered or to which an emulsifier has been added, allowing it to be thinned and cleaned up with water. These paints make it possible to avoid using, or at least reduce volatile organic compounds such as turpentine that may be harmful if inhaled. Water-miscible oil paint can be mixed and applied using the same techniques as traditional oil-based paint, but while still wet it can be removed from brushes, palettes, and rags with ordinary soap and water. One of the ways its water solubility comes from is the use of an oil medium in which one end of the molecule has been engineered to be hydrophilic and thus bind loosely to water molecules, as in a solution. This type of paint is different to those that are engineered to enable cleaning of brushes and application equipment in water but are not in themselves water reducible.
Wet-on-wet, or alla prima, direct painting or au premier coup, is a painting technique in which layers of wet paint are applied to previously administered layers of wet paint. Used mostly in oil painting, the technique requires a fast way of working, because the work has to be finished before the first layers have dried.
Craquelure is a fine pattern of dense cracking formed on the surface of materials. It can be a result of drying, aging, intentional patterning, or a combination of all three. The term is most often used to refer to tempera or oil paintings, but it can also develop in old ivory carvings or painted miniatures on an ivory backing. Recently, analysis of craquelure has been proposed as a way to authenticate art.
A panel painting is a painting made on a flat panel made of wood, either a single piece, or a number of pieces joined together. Until canvas became the more popular support medium in the 16th century, it was the normal form of support for a painting not on a wall (fresco) or vellum, which was used for miniatures in illuminated manuscripts and paintings for the framing.
Rabbit-skin glue is a sizing that also acts as an adhesive. It is essentially refined rabbit collagen, and was originally used as an ingredient in traditional gesso.
Drybrush is a painting technique in which a paint brush that is relatively dry, but still holds paint, is used. Load is applied to a dry support such as paper or primed canvas. The resulting brush strokes have a characteristic scratchy look that lacks the smooth appearance that washes or blended paint commonly have.
A glaze is a thin transparent or semi-transparent layer on a painting which modifies the appearance of the underlying paint layer. Glazes can change the chroma, value, hue and texture of a surface. Glazes consist of a great amount of binding medium in relation to a very small amount of pigment. Drying time will depend on the amount and type of paint medium used in the glaze. The medium, base, or vehicle is the mixture to which the dry pigment is added. Different media can increase or decrease the rate at which oil paints dry.
A wash is a term for a visual arts technique resulting in a semi-transparent layer of colour. A wash of diluted ink or watercolor paint applied in combination with drawing is called pen and wash, wash drawing, or ink and wash. Normally only one or two colours of wash are used; if more colours are used the result is likely to be classified as a full watercolor painting.
Acrylic painting techniques are different styles of manipulating and working with polymer-based acrylic paints. Acrylics differ from oil paints in that they have shorter drying times and are soluble in water. These types of paint eliminate the need for turpentine and gesso, and can be applied directly onto canvas. Aside from painting with concentrated color paints, acrylics can also be watered down to a consistency that can be poured or used for glazes.
Painting is the practice of applying paint, pigment, color or other medium to a solid surface. The medium is commonly applied to the base with a brush, but other implements, such as knives, sponges, and airbrushes, can be used.
Glue-size is a painting technique in which pigment is bound (sized) to cloth with hide glue, and typically the unvarnished cloth was then fixed to the frame using the same glue. Glue-size is also known as distemper, though the term "distemper" is applied variously to different techniques. Glue-size was used because hide glue was a popular binding medium in the 15th century, particularly among artists of the Early Netherlandish period, who used it as an inexpensive alternative to oil. Although a large number of works using this medium were produced, few survive today, mainly because of the high perishability of linen cloth and the solubility of hide glue. Well-known and relatively well-preserved — though substantially damaged — the most notable examples include Quentin Matsys' Virgin and Child with Saints Barbara and Catherine and Dirk Bouts' Entombment. In German the technique is known as Tüchleinfarben, meaning “small cloth colours”, or Tüchlein, derived from the German words Tüch and Lein.
The conservation and restoration of paintings is carried out by professional painting conservators. Paintings cover a wide range of various mediums, materials, and their supports. Painting types include fine art to decorative and functional objects spanning from acrylics, frescoes, and oil paint on various surfaces, egg tempera on panels and canvas, lacquer painting, water color and more. Knowing the materials of any given painting and its support allows for the proper restoration and conservation practices. All components of a painting will react to its environment differently, and impact the artwork as a whole. These material components along with collections care will determine the longevity of a painting. The first steps to conservation and restoration is preventive conservation followed by active restoration with the artist's intent in mind.
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