The art of any culture will show a wide differential of talent. But in no other culture is the difference between ‘masterpiece’ and average work so large as in the tradition of the oil painting. In this tradition the difference is not just a question of skill or imagination, but also of morale. The average work – and increasingly after the seventeenth century – was a work produced more or less cynically: that is to say the values it was nominally expressing were less meaningful to the painter than the finishing of the commission or the selling of his product. Hack work is not the result of either clumsiness or provincialism; it is the result of the market making more insistent demands than the art. The period of the oil painting corresponds with the rise of the open art market. And it is in this contradiction between art and market that the explanations must be sought for what amounts to the contrast, the antagonism existing between the exceptional work and the average.
– John Berger, Ways of Seeing (1972)