On Wednesday we discussed the Hockney hypothesis that optical devices were used by Renaissance artists. We described a number of characteristics of paintings that according to Hockney suggest the use of optical aids. These include: (i) photographic realism (visible in folds and patterns of fabric, reflected light, faces and curved objects such as lutes). (ii) Strange objects such as the distorted skull in the Holbein painting discussed in class. (iii) The film noir effect (blurring of background or foreground objects). (iv) Multiple vanishing points (the Falco effect also often associated with blurring). (v) Multiple viewpoints; collage effect. (vi) Shadows or other indications of excessively bright lighting. (vii) Parity violations (subjects exhibiting unnatural left handedness).