Oil Painting

Oil painting is the process of painting in which drying oils are used as the medium; linseed oil is the best known, but others that have been used in painting include poppy oil, safflower oil and walnut oil. It was long believed that oil painting was invented by Jan van Eyck in the early 15th century, but it is now known that its origins are older and obscurer (the treatise of Theophilus, written probably in the 12th century, describes ‘grinding colours with oil’). There is no doubt, however, that van Eyck revolutionized the technique and brought it to a sudden peak of perfection. He showed the medium's flexibility, its rich and dense colour, its wide range from light to dark, and its ability to achieve both minute detail and subtle blending of tones. Other painters soon took up his innovations—first in northern Europe,then in Italy—and from the 16th century oil colour has been the dominant medium in Europe for serious painting (other than for murals, in which fresco continued to be the norm). Its success has been largely on account of its versatility and ability to show an artist's personal ‘handwriting’, for it can attain any variety of surfaces from porcelain smoothness to violent impasto. Its versatility was increased still further in the 19th century with the invention of the collapsible metal tube (devised in 1841), which made it convenient to work out of doors. In the 20th century, however, acrylic became a serious rival to oil paint.

Oil paint eventually became the principal medium used for creating artworks as its advantages became widely known. Traditional oil painting techniques often begin with the artist sketching the figure onto the canvas with charcoal or a "clean", which is thinned paint. Oil paint can be mixed with turpentine, linseed oil, artist grade mineral spirits or other solvents to create a thinner, faster drying paint. Then the artist builds the figure in layers. 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 form of mediums that can be used in oil painting, these includes cold wax, resins, and varnishes. These additional mediums 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. When looking at original oil paintings, the various traits of oil paint allow one to sense the choices the artist made as they applied the paint. For the viewer, the paint is still, but for the artist, the oil paint is a liquid or semi-liquid and must be moved 'onto' the painting. Traditionally, paint was transferred to the painting surface using paint brush but now there are other methods used like 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 a new one. 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. Scraping may also be used to smooth a portrait before scumbling and glazing. Many oil paintings reveal evidence of scraping on close inspection, particularly when the surface itself is examined. Oil paint dries by oxidation, not evaporation, and is usually dry to the touch in a day to 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.

Materials *Linseed Oil The linseed oil itself comes from the flax seed, and this flax was a common fiber crop. Recent advances 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, 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. *Canvas Traditional artists' canvas is made from linen, but the less expensive cotton fabric has gained popularity. The artist first prepares a wooden frame called a "stretcher" or "strainer". The difference between them 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. The next step is for the artist to apply 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” is made of titanium dioxide 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.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. Traditionally, an artist mixed his or her own paints for each project. Artists could mix colors quickly and easily without having to grind their own pigments. Also, the portability of tube paints allowed for plein air or outdoor painting.

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 applied by the Flemish painters in Northern Europe with pigments ground in linseed oil. More recently this adaptation has been called the "Mixed Technique" or "Mixed

Method". The first coat or “underpainting” is laid down, often painted with egg tempera or turpentine thinned paint. This layer helps to "tone" the canvas, and cover the white of the gesso. Many artists use this layer to sketch out the composition. This layer can be adjusted before moving forward, which is 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. This layer is then left to dry before applying details. The artist may apply several layers of details, using a technique called 'fat over lean.' This means that each additional layer of paint is a bit oilier than the layer below, to allow proper drying. As a painting receives additional layers, the paint itself must become more oleo saturated (leaner to fatter) so that the final painting will not crack and peel. After it is dry, the artist might apply “glaze” to the painting, which is a thin, transparent layer to seal the surface. A classical work might take weeks or even months to layer the paint, but the most skilled early artists, such as Jan van Eyck, could have worked more quickly using the Wet-on wet method of painting for some details. Click here for more information on How to Paint