What is a camera obscura anyway?
Charles Falco, David Hockney’s partner and scientist working with optics, describes the camera obscura “as something to make, not something to buy.”18 He recommends working in a bathroom with a small window in which the right ambient level of lighting can easily be achieved. To enhance the camera obscura effect either a shaving mirror (concave) or a magnifying glass (a biconvex lens) can be utilized. If a shaving mirror is being used it should be aimed at the wall alongside the small window. An upside-down image will appear on the wall. With a magnifying glass the image must be reflected onto the wall opposite the small window. The image will not only be upside-down, but will also be reversed. The concave mirror is considered by Hockney and Falco to have been the first technical improvement on the natural camera obscura effect, while they consider the refractive biconvex lens to be the next step.19 It is the concave mirror effect that Stork erroneously uses in his rebuttal rather than
