Summer, 1978, Nils   # 36.  Oil on collage after a photograph from National Geographic Magazine September 1977.  5 1/4" x 9 1/4" ( 13.5 cm x 23.5 cm)

Most people know that the time honoured medium for creating fine paintings is oil.  More specifically, linseed oil.  One of the major achievements of the early Renaissance was the refinement (but probably not the discovery) of the oil technique - by Flemish painters, most notably Jan van Eyck.  At that time (and even previous to it), experiments had been carried out with linseed, poppyseed, walnut, and hempseed oils.   

Like any discovery, it is as much due to the technology of the time, as it is to the needs of that moment in time.  Mayer notes that artists turned to oils in the fifteenth century to create effects in easel painting for new client demands that traditional tempera paints could not render.  What seems clear is that the paintings of the Flemish Masters of the Fifteenth Century can literally be  seen as oil enhancements applied over the surface of a traditional  tempera painting rather than totally new discoveries rising from the dust.