Oil painting

Oil painting

Overview
Oil painting is the process of painting with pigment
Pigment
A pigment is a material that changes the color of reflected or transmitted light as the result of wavelength-selective absorption. This physical process differs from fluorescence, phosphorescence, and other forms of luminescence, in which a material emits light.Many materials selectively absorb...

s that are bound with a medium of drying oil
Drying oil
A drying oil is an oil that hardens to a tough, solid film after a period of exposure to air. The oil hardens through a chemical reaction in which the components crosslink by the action of oxygen . Drying oils are a key component of oil paint and some varnishes...

—especially in early modern Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...

, linseed oil
Linseed oil
Linseed oil, also known as flaxseed oil, is a clear to yellowish oil obtained from the dried ripe seeds of the flax plant . The oil is obtained by cold pressing, sometimes followed by solvent extraction...

. Often an oil such as linseed was boiled with a resin such as pine resin or even frankincense
Frankincense
Frankincense, also called olibanum , is an aromatic resin obtained from trees of the genus Boswellia, particularly Boswellia sacra, B. carteri, B. thurifera, B. frereana, and B. bhaw-dajiana...

; these were called 'varnishes' and were prized for their body and gloss. Other oils occasionally used include poppyseed oil
Poppyseed oil
Poppyseed oil is an edible oil from poppy seeds . The oil has culinary and pharmaceutical uses, as well as long established uses in the making of paints, varnishes, and soaps.Poppy seeds yield 45–50% oil...

, walnut oil
Walnut oil
Walnut oil is oil extracted from English walnuts . It is about 50% linoleic acid, an essential omega-6 fatty acid. Walnut oil is also a good source of omega-3 fatty acids which are also essential to human nutrition....

, and safflower oil. These oils confer various properties to the oil paint
Oil paint
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...

, such as less yellowing or different drying times.
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Encyclopedia
Oil painting is the process of painting with pigment
Pigment
A pigment is a material that changes the color of reflected or transmitted light as the result of wavelength-selective absorption. This physical process differs from fluorescence, phosphorescence, and other forms of luminescence, in which a material emits light.Many materials selectively absorb...

s that are bound with a medium of drying oil
Drying oil
A drying oil is an oil that hardens to a tough, solid film after a period of exposure to air. The oil hardens through a chemical reaction in which the components crosslink by the action of oxygen . Drying oils are a key component of oil paint and some varnishes...

—especially in early modern Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...

, linseed oil
Linseed oil
Linseed oil, also known as flaxseed oil, is a clear to yellowish oil obtained from the dried ripe seeds of the flax plant . The oil is obtained by cold pressing, sometimes followed by solvent extraction...

. Often an oil such as linseed was boiled with a resin such as pine resin or even frankincense
Frankincense
Frankincense, also called olibanum , is an aromatic resin obtained from trees of the genus Boswellia, particularly Boswellia sacra, B. carteri, B. thurifera, B. frereana, and B. bhaw-dajiana...

; these were called 'varnishes' and were prized for their body and gloss. Other oils occasionally used include poppyseed oil
Poppyseed oil
Poppyseed oil is an edible oil from poppy seeds . The oil has culinary and pharmaceutical uses, as well as long established uses in the making of paints, varnishes, and soaps.Poppy seeds yield 45–50% oil...

, walnut oil
Walnut oil
Walnut oil is oil extracted from English walnuts . It is about 50% linoleic acid, an essential omega-6 fatty acid. Walnut oil is also a good source of omega-3 fatty acids which are also essential to human nutrition....

, and safflower oil. These oils confer various properties to the oil paint
Oil paint
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...

, 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
Buddhism
Buddhism is a religion and philosophy encompassing a variety of traditions, beliefs and practices, largely based on teachings attributed to Siddhartha Gautama, commonly known as the Buddha . The Buddha lived and taught in the northeastern Indian subcontinent some time between the 6th and 4th...

 Paintings by India
India
India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...

n and Chinese
China
Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...

 painters in western Afghanistan
Afghanistan
Afghanistan , officially the Islamic Republic of Afghanistan, is a landlocked country located in the centre of Asia, forming South Asia, Central Asia and the Middle East. With a population of about 29 million, it has an area of , making it the 42nd most populous and 41st largest nation in the world...

 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. Oil paint eventually became the principal medium used for creating artworks as its advantages became widely known. The transition began with Early Netherlandish painting
Early Netherlandish painting
Early Netherlandish painting refers to the work of artists active in the Low Countries during the 15th- and early 16th-century Northern renaissance, especially in the flourishing Burgundian cities of Bruges and Ghent...

 in northern Europe, and by the height of the Renaissance
Renaissance
The Renaissance was a cultural movement that spanned roughly the 14th to the 17th century, beginning in Italy in the Late Middle Ages and later spreading to the rest of Europe. The term is also used more loosely to refer to the historical era, but since the changes of the Renaissance were not...

 oil painting techniques had almost completely replaced tempera
Tempera
Tempera, also known as egg tempera, is a permanent fast-drying painting medium consisting of colored pigment mixed with a water-soluble binder medium . Tempera also refers to the paintings done in this medium. Tempera paintings are very long lasting, and examples from the 1st centuries AD still exist...

 paints in the majority of Europe.

In recent years, water miscible oil paint
Water miscible oil paint
Water miscible oil paint is a modern variety of oil paint engineered to be thinned and cleaned up with water, thus making it possible to avoid using chemicals such as turpentine, whose fumes may be harmful if inhaled...

 has come to prominence, to some extent replacing the usage of traditional oils. Water soluble paints contain an emulsifier which allows them to be thinned with water (rather than with paint thinner
Paint thinner
A paint thinner is a solvent used to thin oil-based paints or clean up after their use, although all such solvents have other uses. Commercially, "paint thinner" is usually a name for mineral spirits.Products used as paint thinners include:*Mineral spirits...

), and allows very fast drying times (1-3 days) when compared with traditional oils (1-3 weeks).

Techniques



Traditional oil painting techniques often begin with the artist sketching the subject onto the canvas with charcoal or thinned paint. Oil paint
Oil paint
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...

 is usually mixed with linseed oil, artist grade mineral spirits or other solvents to create a thinner, faster or slower drying paint. Because these 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
Fat over lean
Fat over lean refers to the principle in oil painting of applying paint with a higher oil to pigment ratio over paint with a lower oil to pigment ratio to ensure a stable paint film, since it is believed that the paint with the higher oil content remains more flexible.Oil paint dries at different...

'. 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
Palette knife
A palette knife is a blunt tool used for mixing or applying paint, with a flexible steel blade. It is primarily used for mixing paint colors, paste, etc., or for marbling, decorative endpapers, etc...

 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 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
Evaporation
Evaporation is a type of vaporization of a liquid that occurs only on the surface of a liquid. The other type of vaporization is boiling, which, instead, occurs on the entire mass of the liquid....

, and is usually dry to the touch within a span of two weeks. It is generally dry enough to be varnish
Varnish
Varnish is a transparent, hard, protective finish or film primarily used in wood finishing but also for other materials. Varnish is traditionally a combination of a drying oil, a resin, and a thinner or solvent. Varnish finishes are usually glossy but may be designed to produce satin or semi-gloss...

ed 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
Tempera
Tempera, also known as egg tempera, is a permanent fast-drying painting medium consisting of colored pigment mixed with a water-soluble binder medium . Tempera also refers to the paintings done in this medium. Tempera paintings are very long lasting, and examples from the 1st centuries AD still exist...

 and related media in Europe indicates that oil painting was discovered there independently.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
Tempera
Tempera, also known as egg tempera, is a permanent fast-drying painting medium consisting of colored pigment mixed with a water-soluble binder medium . Tempera also refers to the paintings done in this medium. Tempera paintings are very long lasting, and examples from the 1st centuries AD still exist...

 paints.

Most Renaissance
Renaissance
The Renaissance was a cultural movement that spanned roughly the 14th to the 17th century, beginning in Italy in the Late Middle Ages and later spreading to the rest of Europe. The term is also used more loosely to refer to the historical era, but since the changes of the Renaissance were not...

 sources, in particular Vasari, credited northern European painters of the 15th century, and Jan van Eyck
Jan van Eyck
Jan van Eyck was a Flemish painter active in Bruges and considered one of the best Northern European painters of the 15th century....

 in particular, with the "invention" of painting with oil media on wood panel
Panel painting
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 or vellum, which was used for...

, however Theophilus
Theophilus Presbyter
Theophilus Presbyter is the pseudonymous author or compiler ofa Latin text containing detailed descriptions of various medieval arts, a text commonly known as the Schedula diversarum artium or De diversis artibus , probably first compiled between 1100 and 1120...

 (Roger of Helmarshausen
Roger of Helmarshausen
Roger of Helmarshausen was a well-known goldsmith and metalwork artist, and also a Benedictine monk.-Artistic career:Roger is first heard of in connection with Stavelot Abbey in the Meuse valley, a centre of Mosan art, and especially goldsmith's work. He worked between 1100 and 1107 in St....

?) 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
Early Netherlandish painting
Early Netherlandish painting refers to the work of artists active in the Low Countries during the 15th- and early 16th-century Northern renaissance, especially in the flourishing Burgundian cities of Bruges and Ghent...

 in the 15th century was however the first to make oil the usual painting medium, and explore the use of layers and glaze
Glaze (painting technique)
Glazes can change the chroma, value, hue and texture of a surface. 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...

s, followed by the rest of Northern Europe, and only then Italy. Early works were still panel painting
Panel painting
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 or vellum, which was used for...

s on wood, but around the end of the 15th century canvas
Canvas
Canvas is an extremely heavy-duty plain-woven fabric used for making sails, tents, marquees, backpacks, and other items for which sturdiness is required. It is also popularly used by artists as a painting surface, typically stretched across a wooden frame...

 became more popular, as it was cheaper, easier to transport, and allowed larger works. Venice
Venice
Venice is a city in northern Italy which is renowned for the beauty of its setting, its architecture and its artworks. It is the capital of the Veneto region...

, where sail-canvas was easily available, led the move. The popularity of oil spread through Italy from the North, starting in Venice
Venice
Venice is a city in northern Italy which is renowned for the beauty of its setting, its architecture and its artworks. It is the capital of the Veneto region...

 in the late 15th century. By 1540 the previous method for painting on panel, tempera
Tempera
Tempera, also known as egg tempera, is a permanent fast-drying painting medium consisting of colored pigment mixed with a water-soluble binder medium . Tempera also refers to the paintings done in this medium. Tempera paintings are very long lasting, and examples from the 1st centuries AD still exist...

 had become all but extinct, although Italians continued to use fresco
Fresco
Fresco is any of several related mural painting types, executed on plaster on walls or ceilings. The word fresco comes from the Greek word affresca which derives from the Latin word for "fresh". Frescoes first developed in the ancient world and continued to be popular through the Renaissance...

 for wall paintings, which was more difficult in Northern climates.

Ingredients


The linseed oil itself comes from the flax
Flax
Flax is a member of the genus Linum in the family Linaceae. It is native to the region extending from the eastern Mediterranean to India and was probably first domesticated in the Fertile Crescent...

 seed, a common fiber crop. It is interesting to note that linen
Linen
Linen is a textile made from the fibers of the flax plant, Linum usitatissimum. Linen is labor-intensive to manufacture, but when it is made into garments, it is valued for its exceptional coolness and freshness in hot weather....

, an important "support" for oil painting (see below) also comes from the flax plant. Safflower
Safflower
Safflower is a highly branched, herbaceous, thistle-like annual. It is commercially cultivated for vegetable oil extracted from the seeds. Plants are 30 to 150 cm tall with globular flower heads having yellow, orange or red flowers. Each branch will usually have from one to five flower heads...

 oil, or the more traditional walnut
Walnut
Juglans is a plant genus of the family Juglandaceae, the seeds of which are known as walnuts. They are deciduous trees, 10–40 meters tall , with pinnate leaves 200–900 millimetres long , with 5–25 leaflets; the shoots have chambered pith, a character shared with the wingnuts , but not the hickories...

 or poppyseed oil
Poppyseed oil
Poppyseed oil is an edible oil from poppy seeds . The oil has culinary and pharmaceutical uses, as well as long established uses in the making of paints, varnishes, and soaps.Poppy seeds yield 45–50% oil...

, are 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
Chemistry
Chemistry is the science of matter, especially its chemical reactions, but also its composition, structure and properties. Chemistry is concerned with atoms and their interactions with other atoms, and particularly with the properties of chemical bonds....

 have produced modern water miscible oil paint
Water miscible oil paint
Water miscible oil paint is a modern variety of oil paint engineered to be thinned and cleaned up with water, thus making it possible to avoid using chemicals such as turpentine, whose fumes may be harmful if inhaled...

s that can be used with and cleaned up with water. Small alterations in the molecular
Molecule
A molecule is an electrically neutral group of at least two atoms held together by covalent chemical bonds. Molecules are distinguished from ions by their electrical charge...

 structure of the oil creates this water miscible property.

A still-newer type of paint, heat-set oils, remain liquid until heated to 265–280 °F
Fahrenheit
Fahrenheit is the temperature scale proposed in 1724 by, and named after, the German physicist Daniel Gabriel Fahrenheit . Within this scale, the freezing of water into ice is defined at 32 degrees, while the boiling point of water is defined to be 212 degrees...

 (130–138 °C
Celsius
Celsius is a scale and unit of measurement for temperature. It is named after the Swedish astronomer Anders Celsius , who developed a similar temperature scale two years before his death...

) 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
Chemical synthesis
In chemistry, chemical synthesis is purposeful execution of chemical reactions to get a product, or several products. This happens by physical and chemical manipulations usually involving one or more reactions...

 oily liquid, imbedded with a heat sensitive curing agent"), the paintings resemble oil paintings and are usually shown as oil paintings.

Supports for oil painting


Traditional artists' canvas is made from linen
Linen
Linen is a textile made from the fibers of the flax plant, Linum usitatissimum. Linen is labor-intensive to manufacture, but when it is made into garments, it is valued for its exceptional coolness and freshness in hot weather....

, but less expensive cotton
Cotton
Cotton is a soft, fluffy staple fiber that grows in a boll, or protective capsule, around the seeds of cotton plants of the genus Gossypium. The fiber is almost pure cellulose. The botanical purpose of cotton fiber is to aid in seed dispersal....

 fabric has gained popularity. The artist first prepares a wooden frame called a "stretcher" or "strainer". The difference between the first and second 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 (size), (modern painters will use rabbit skin glue) 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
Gesso
Gesso is a white paint mixture consisting of a binder mixed with chalk, gypsum, pigment, or any combination of these...

" is made of titanium dioxide
Titanium dioxide
Titanium dioxide, also known as titanium oxide or titania, is the naturally occurring oxide of titanium, chemical formula . When used as a pigment, it is called titanium white, Pigment White 6, or CI 77891. Generally it comes in two different forms, rutile and anatase. It has a wide range of...

 with an acrylic binder. It is frequently used on canvas, whereas real gesso is not suitable for that application. 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, not canvas. It is possible to tone the gesso to a particular color, but most store-bought gesso is white. The gesso layer will tend to draw the oil paint into the porous surface, depending on the thickness of the gesso layer. Excessive or uneven gesso layers are sometimes visible in the surface of finished paintings as a change in the layer 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 artist materials. The main separation from size 0 (toile de 0) to size 120 (toile de 120) is divided in separate runs for figures (figure), landscapes (paysage) and marines (marine) which more or less keep the diagonal. Thus a 0 figure corresponds in height with a paysage 1 and a marine 2.

Although surfaces like linoleum
Linoleum
Linoleum is a floor covering made from renewable materials such as solidified linseed oil , pine rosin, ground cork dust, wood flour, and mineral fillers such as calcium carbonate, most commonly on a burlap or canvas backing; pigments are often added to the materials.The finest linoleum floors,...

, wooden panel
Panel painting
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 or vellum, which was used for...

, paper
Paper
Paper is a thin material mainly used for writing upon, printing upon, drawing or for packaging. It is produced by pressing together moist fibers, typically cellulose pulp derived from wood, rags or grasses, and drying them into flexible sheets....

, slate
Slate
Slate is a fine-grained, foliated, homogeneous metamorphic rock derived from an original shale-type sedimentary rock composed of clay or volcanic ash through low-grade regional metamorphism. The result is a foliated rock in which the foliation may not correspond to the original sedimentary layering...

, pressed wood
Pressed wood
Pressed wood is any engineered wood building and furniture construction material made from wood veneers, particles, or wood fibers bonded together with an adhesive under heat and pressure.-See also:*Engineered wood*Fiberboard*Glued laminated timber...

, and cardboard
Paperboard
Paperboard is a thick paper based material. While there is no rigid differentiation between paper and paperboard, paperboard is generally thicker than paper. According to ISO standards, paperboard is a paper with a basis weight above 224 g/m2, but there are exceptions. Paperboard can be single...

 have been used, the most popular surface since the 16th century has been canvas
Canvas
Canvas is an extremely heavy-duty plain-woven fabric used for making sails, tents, marquees, backpacks, and other items for which sturdiness is required. It is also popularly used by artists as a painting surface, typically stretched across a wooden frame...

, 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 gives an advantage.

Process


The artist might sketch an outline of their subject prior to applying pigment to the surface. "Pigment
Pigment
A pigment is a material that changes the color of reflected or transmitted light as the result of wavelength-selective absorption. This physical process differs from fluorescence, phosphorescence, and other forms of luminescence, in which a material emits light.Many materials selectively absorb...

" may be any number of natural substances with color, such as sulphur for yellow or cobalt for blue. The pigment is mixed with oil, usually linseed oil but other oils may be used as well. The various oils dry differently, creating assorted effects.

Traditionally, artists mixed their own paints from raw pigments that they often ground themselves and medium. This made portability difficult and kept most painting activities confined to the studio. This changed in the late 1800s, when oil paint in tubes became widely available. Artists could mix colors quickly and easily, which enabled, for the first time, relatively convenient plein air (outdoor) painting (a common approach in French Impressionism
Impressionism
Impressionism was a 19th-century art movement that originated with a group of Paris-based artists whose independent exhibitions brought them to prominence during the 1870s and 1880s...

).

The artist most often uses a brush to apply the paint. Brushes are made from a variety of fibers to create different effects. For example, brushes made with hog's 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 mink. This hair keeps a superfine point, has smooth handling, and good memory (it returns to its original point when lifted off the canvas); this is known to artists as a brush's "snap."

In the past few decades, many synthetic brushes have come on the market. These are very durable and can be quite good, as well as cost efficient. Floppy fibers with no snap, such as squirrel hair, are generally not used by oil painters. Sizes of brushes also are widely varied and used for different effects. 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 with shorter brush hairs. "Filbert" is a flat with rounded corners. "Egbert" is a very long "Filbert" and is rare. 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. Some artists even paint with their fingers.


Most artists paint in layers, which is simply called "Indirect Painting". The method was first perfected through an adaptation of the egg tempera painting technique and was applied by the Flemish painters in Northern Europe with pigments ground in linseed oil. More recently, this approach has been called the "Mixed Technique" or "Mixed Method". The first coat (also called "underpainting
Underpainting
In art, an underpainting is an initial layer of paint applied to a ground, which serves as a base for subsequent layers of paint. Underpaintings are often monochromatic and help to define colour values for later painting...

") 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 moving forward, an advantage over the 'cartooning' method used in Fresco
Fresco
Fresco is any of several related mural painting types, executed on plaster on walls or ceilings. The word fresco comes from the Greek word affresca which derives from the Latin word for "fresh". Frescoes first developed in the ancient world and continued to be popular through the Renaissance...

 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. This mosaic layer is then left to dry before applying details.

Artists in later periods, such as the impressionist era, often used this Wet-on-wet
Wet-on-wet
Wet-on-wet is a painting technique in which layers of wet paint are applied to previous layers of wet paint. This technique requires a fast way of working, because the art work has to be finished before the first layers have dried....

 method more widely, blending the wet paint on the canvas without following the Renaissance-era approach of layering and glazing. This method is also called "alla prima
Alla prima
-Definition:alla prima is a painting technique done mostly in oils, in which the work is completed before the first layer of painting has dried up or is still wet, such as the 'impressionist' technique or 'Glaze '...

". This method was created due to the advent of painting outdoors, instead of inside a studio. 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 blend of both techniques, which can add bold color (wet-on-wet) as well as 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 damar 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 that the surfaces remain varnish-free.

See also

  • The Artist's Handbook of Materials and Techniques
    The Artist's Handbook of Materials and Techniques
    The Artist's Handbook of Materials and Techniques is a reference book by Ralph Mayer. Intended by the author for use by professional artists, it deals mostly with the chemical and physical properties of traditional painterly materials such as oil, tempera, and solvents...

    , comprehensive reference book by Ralph Mayer (1940)
  • Faux painting
    Faux painting
    Faux painting or faux finishing are terms used to describe a wide range of decorative painting techniques. The naming comes from the French word faux, meaning false, as these techniques started as a form of replicating materials such as marble and wood with paint, but has subsequently come to...

  • History of painting
    History of painting
    The history of painting reaches back in time to artifacts from pre-historic humans, and spans all cultures. It represents a continuous, though periodically disrupted tradition from Antiquity. Across cultures, and spanning continents and millennia, the history of painting is an ongoing river of...

  • Lists of painters
  • Oil sketch
    Oil sketch
    An Oil sketch or oil study is an artwork made primarily in oil paints that is more abbreviated in handling than a fully finished painting. Originally these were created as preparatory studies or modelli, especially so as to gain approval for the design of a larger commissioned painting...

  • Old Master
    Old Master
    "Old Master" is a term for a European painter of skill who worked before about 1800, or a painting by such an artist. An "old master print" is an original print made by an artist in the same period...

  • Paper marbling
    Paper marbling
    Paper marbling is a method of aqueous surface design, which can produce patterns similar to smooth marble or other stone. The patterns are the result of color floated on either plain water or a viscous solution known as size, and then carefully transferred to an absorbent surface, such as paper or...