ABSTRACT
In 2000, the contemporary painter, photographer and set designer David Hockney claimed that some Western artists secretly built optical projectors, projected portions of a sunlit scene or subject onto their supports. This chapter describes the optical tracing theory in a bit more detail and explores its scholarly and even philosophical foundations in order to determine what aspects of the claims can—and cannot—be tested, even in principle. It also considers the image evidence from key paintings and the arguments concerning the projection claim, both pro and con; in particular alternative non-optical explanations for the "optical" evidence. The chapter turns to the important matter of contemporary documentary evidence—or lack of evidence—in support of the projection claim and the proponents' speculation that this lack of evidence is due to artists protecting "trade secrets" or fearing the Inquisition. It examines the physical evidence and material culture of the time to see if adequate materials and knowledge about appropriate projections existed.
