Technique of Oil Painting

OIL PAINTING, TECHNIQUE OF. As the musician must be taught, and the subtlest of harmonies are subject to material limitations, so the art of the painter must be learned, and he, more perhaps than any other artist, is bound by severe mate rial necessities. It is not intended here to give instruction in the art of painting or to express individual preferences. The object in view is rather, taking as a basis the various methods employed by the great masters, to give an account of the technical considera tions which all painters are obliged to bear in mind.

One thing to be noted in a consideration of painting is that there is a wider divergence in the techniques employed than in that of any other art. We should not find this diversity so ex tensive if, instead of discussing the technique of oil painting, we were analysing the technical methods of the Primitives who painted with wax, yolk of egg, or in fresco. Whatever difference there may be in the appearance of a painting by Cimabue and one by Mantegna, it will be very much less than the difference be tween the work of two artists painting after the invention of oil painting.

It may not be necessary to recall that all the colours used in painting, whether they are of mineral or vegetable origin, finally appear in the form of more or less soft stones which are ground to a powder in order to be used. These coloured powders require some binding vehicle in order to bring them to a sufficient con sistency. The vehicle may be wax, mortar, glue, glycerine or resin. The brothers Van Eyck are generally believed to have been the first to mix their colours with oil. From the numerous contro versies to which their discovery has given rise, it would seem that the principal achievement of the brothers Van Eyck was that they perfected, for the purpose of painting easel pictures, the results of the much earlier practice which had been to use oil for the paint ing of large surfaces, and especially for the painting of boats. The effect of oil in rendering colours durable had been observed previously; pictures painted with yolk of egg had been covered with a coating of oil which was hardened by drying in the sun and which at once protected and intensified the colours.

Once, however, the practical method of grinding colours with oil had been discovered, a vast field of technical research opened up before painters, and they were naturally tempted to explore the new possibilities which were provided. It was this possibility of variety in technical methods which, in combination with the individual genius of the great masters, enabled the art of oil paint ing strictly so called to rise to such great heights at the time of the Renaissance.

The Support.

Oil paint will adhere to a number of materials, and during the ages painters have experimented in painting on a number of metal and mineral grounds. Slate, marble and alabaster have been used, but comparatively rarely owing to their fragility. Copper has also been utilised, though, of course, only for works of small size. Paper deserves special mention. Far from being an inferior material as might be supposed, paper is perhaps the most suitable ground for works of a spontaneous character. It was used by Flemish painters, who glued it to wood panels or canvases by means of casein. Later, in the 18th and early 19th centuries, a large number of French painters used this process, which was of great value in setting off their brilliant execution. No other material gives such transparency to browns or so much depth to blacks.

Practical considerations have, however, led most painters to prefer two supporting materials : first, wood, and second, canvas. Up to the end of the Renaissance period wood was generally employed; but it would be an error to suppose that the change to canvas was a sudden one. There are a number of examples of wood panels upon which a fine canvas has been glued. Besides, although the use of canvas became very frequent after the Renais sance, it cannot be said to have been universal, since at all periods in the history of painting, including the present, many artists have painted on wood. In Italy the white poplar was generally used ; in Flanders they used oak. To-day mahogany, which does not crack so easily as oak, is often used.