"In keeping with the traditions of the Venetians, El Greco's canvas ground was often red. However, in contrast to the Italian opaque ground, his red color was thinly laid on the white priming of the canvas, though not... as... . ...I believe that this ground was not made of red bole, but that it was an oil ground. The characteristic... brushstroke and the blending of his colors point to the use of a heat-treated oil rather than raw . ...[P]rincipally one layer of pigment was applied on top of the underpainting. ...The painter evidently did not labor over his paintings. The relative speed with which he advanced his work can be realized from the fact that "The Burial of Count Orgaz," his greatest painting, was delivered [in] fourteen months... Considering that he executed many other commissions during that... period and that his paintings were not the result of teamwork... he must have worked rapidly. ...El Greco's technique must be regarded as... the soundest method of oil painting. ...[T]here are practically no cracks or deteriorations of any kind... on most of his paintings."