 The first proposal, on which cinematic motion is a secondary quality, threatens to destroy the distinction between the apparent and the illusory. It suggests a way of reinterpreting any case of perceptual illusion as a case involving the ascription of secondary qualities. That is, unless it can be shown that there are independent means of checking that we are mistaken about genuine illusions. But even if this can be shown, a problem remains: While there may not be an independent check for the motion in an image, there is likewise no independent check for a genuine illusion of color. Given the contrived conditions of movie viewing, there is more reason to think of cinematic motion as akin to an illusory, than to a genuine, experience of color. With the introduction of digital projection, the conditions are arguably even more contrived. For it is not just movement in the image but the image itself that is constituted by rapid flashes of light. And the technology involved is far less accessible than that of a traditional mechanical projector in the sense that one cannot, just by looking at the projection device, see (roughly) how it works. In this way, an analysis of digital movie projection serves to reinforce the traditional assumption that cinema is an art of illusion. In addition, however, the analysis suggests that the illusion at the heart of cinema is particularly impenetrable—akin to an illusion of color, and thus an illusion of a mere appearance that cannot be checked (Thomson-Jones 2013).