An oil sketch or oil study is an artwork made primarily in oil paint in preparation for a larger, finished work. Originally these were created as preparatory studies or modelli, especially so as to gain approval for the design of a larger commissioned painting. They were also used as designs for specialists in other media, such as printmaking or tapestry, to follow. Later they were produced as independent works, often with no thought of being expanded into a full-size painting. The usual medium for modelli was the drawing, but an oil sketch, even if done in a limited range of colours, could better suggest the tone of the projected work. It is also possible to more fully convey the flow and energy of a composition in paint. For a painter with exceptional technique, the production of an oil sketch may be as rapid as that of a drawing, and many practitioners had superb brush skills. In its rapidity of execution the oil sketch may be used not only to express movement and transient effects of light and color, its gestural nature may even represent a mimetic parallel to the action of the subject. History One of the earliest artists to produce oil sketches was Polidoro da Caravaggio, a fine draftsman and pupil of Raphael, but not one who had passed through the traditional Florentine training, with its emphasis on drawing. His are all apparently related to works later done on a larger scale, and are themselves relatively large and on panel, with examples in the National Gallery, London and Courtauld Institute of Art being 75 and 65 cm tall respectively. Sometimes a number of sketches for the same composition have survived. In the early 17th century the oil sketch became widely used, as it was suited to conveying the drama of Baroque art. Rubens made great use of them, as working studies, and as modelli for clients, his own assistants, engravers and tapestry-makers. Their degree of finish varies accordingly. Rubens' working practices influenced others, such as Anthony van Dyck, who did not normally use oil sketches for the portraits that were the bulk of his output, but did for his print series the Iconographie, and for other works such as a projected series of tapestries and some religious paintings. The Magistrate of Brussels, recognised in England in 2013, may be a Van Dyck portrait oil sketch. Perhaps the first to