Editing Oil painting (section)

==Supports for oil painting==
[[Image:Splined Canvas.jpg|thumb|[[Splined canvas]]|alt=A square canvas rests on top of another with its back showing a thick frame of wood.]]

The earliest oil paintings were almost all [[panel painting]]s on wood, which had been [[Wood drying|seasoned]] and prepared in a complicated and rather expensive process with the panel constructed from several pieces of wood, although such support tends 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 painting]]s even in the 19th century. [[Portrait miniature]]s 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 "[[sizing|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 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 on 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 still is—supported by the main suppliers of artists' materials. Size 0 (''toile de 0'') to size 120 (''toile de 120'') is divided into separate "runs" for figures (''figure''), landscapes ({{lang|fr|paysage}}), and marines ({{lang|fr|marine}}) that more or less preserve the diagonal. Thus a ''0 figure'' corresponds in height with a ''paysage 1'' and a ''marine 2''.<ref>{{Cite journal|last= Haaf|first= Beatrix|title=Industriell vorgrundierte Malleinen. Beiträge zur Entwicklungs-, Handels- und Materialgeschichte| journal=Zeitschrift für Kunsttechnologie und Konservierung|volume = 1|pages = 7–71|year = 1987}}</ref>

Although surfaces like [[linoleum]], [[panel painting|wooden panel]], [[paper]], [[slate]], [[pressed wood]], [[Masonite]], and [[Paperboard|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. The 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.

Some artists are now painting directly onto prepared Aluminium Composite Material (ACM) panels. Others combine the perceived benefits of canvas and panel by gluing canvas onto panels made from ACM, Masonite or other material.