<P> 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 . </P> <P> 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 . </P> <P> 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 . </P> <P> Oil paint is made by mixing pigments of colors with an oil medium . Different colors are made, or purchased premixed, before painting begins, but 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 of different colors . 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; the appearance of many old paintings today is very different from the original . 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 . </P>

What type of paper is used for oil painting