David Hockney's 'Secret Knowledge' Argues Old Masters Used Optical Tools

David Hockney's book 'Savoirs secrets' (Secret Knowledge), published by Éditions du Seuil, presents a controversial thesis that Western Old Masters from the 1430s onward used optical devices such as concave mirrors, camera obscura, and later camera lucida to trace projections onto flat surfaces. Hockney provides visual, documentary, and scientific evidence to argue that this practice was both early and widespread, challenging art historical certainties. He points to distortions, discontinuities, disproportions, and 'optical artifacts' in paintings, as well as an increase in left-handed figures, as evidence. The book suggests that artists 'cheated' without diminishing the quality of their work, demystifying innate artistic genius and the heroic image of the solitary artist. An accompanying exhibition of Hockney's work is on view at Galerie Lelong in Paris until January 12.