Oils, lacquers, turpentine, and additives comprise a group of
painting auxiliary materials. Skillful use of mediums, including mixing them with paints,
applying thin preliminary layers of lacquer in multilayer painting,
finishing a fully dried painting with lacquer for a sheen or matte finish, etc.,
facilitates the achievement of desired effects and increases the life of a
painting.
Carefully chosen natural ingredients such as natural tars, linseed oil and soft resin turpentine are used for manufacturing these auxiliary materials. 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 create a thinner, faster or slower drying paint. 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 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. Linseed Oil Linseed oil is made from the seeds of the flax plant. It adds gloss and transparency to paints and is available in several forms. Linseed oil dries the most thoroughly of all the oils used as mediums. Use linseed oil for an underpainting or in the bottom layers of any oil painting done wet-on-dry. Refined linseed oil is a popular, all-purpose, pale to light yellow oil which dries withing three to five days. Cold-pressed linseed oil dries slightly faster than refined linseed oil and is considered to be the best quality linseed oil. Stand oil is a thicker processed form of linseed oil, with a slower drying time (about a week to be dry to the touch, though it will remain tacky for some time). It's ideal for glazing (when mixed with a diluent or solvent such as turpentine) and produces a smooth, enamel-like finish without any visible brush marks. Turpentines Turpentine (also called spirit of turpentine, oil of turpentine, wood turpentine and gum turpentine) is a fluid obtained by the distillation of resin from trees, mainly pine trees. Turpentines are used as thinners for artistic oil paints and lacquers as well as for removing paints from the tools (cleaning brushes, palettes, etc.). They: - evaporate quickly - increase penetration of oils in paints in between layers increasing the durability of paint layers - improve visual qualities of paints. Pinenes form the primary constituents of turpentine. As the name suggests, pinenes are important constituents of pine resin. Varnishes Lacquers or varnishes are solutions of natural tars and oils in fluid turpentine used traditionally in manufacturing of lacquers. Lacquers are used: - as additives for oil paints during painting (lacquers for the palette) to prevent wrinkling and dimming of layers of paints, to preserve brightness and purity of colours, to increase intensity of hue and to decrease the possibility of appearance of a yellow tint in the film - as intermediary layers in order to prevent tarnishing and to increase adhesiveness of layers of paint - for protecting paintings - for fixating pencil, charcoal or pastel drawings (fixative) .
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