Hockney’s assumptions

Yet, if Hockney is right, why is there still so much confusion? And why are so few scholars supporting him? I believe Hockney added to the turmoil through making a number of misleading assumptions in his publication Secret Knowledge. One is that the camera lucida (technically) and the camera obscura have a place side by side, other than as possible drawing aids. William Wollaston’s camera lucida, which was introduced in 1807, is not anything like a modern camera (the heir to the camera obscura). It is a small optical instrument that incorporates a prism, and is used to facilitate drawing in daylight. The reflection does not actually fall onto the drafting paper as the camera projection does, being an optical illusion seen only by the user. Another assumption Hockney makes is that everyone would know what a camera obscura is (like saying the word television). But the camera obscura is not a material thing it is simply a phenomenon. Jonathan Crary, author of Techniques of the observer: on vision and modernity in the nineteenth century, explains: “It has been known for at least two thousand years that when light passes through a small hole into a dark, enclosed interior, an inverted image will appear on the wall opposite the hole.”¹⁶ The Latin name camera obscura (literally dark room) describing this effect, is attributed to the seventeenth-century German astronomer Johannes Kepler (1571-1630).¹⁷