History of Optics in Art
The Lost Secrets of the Old Masters:This is a very interesting interview with David Hockney, where he explains and demonstrates the use of camera obscuras and camera lucidas in the artwork of the Old Masters chronicled in his book “Secret Knowledge: Rediscovering the Lost Techniques of the Old Masters”.
An article about Hockney’s theory: click here.
A study of Hockney's finding: click here.
A History of How Optics Has Helped Artists Create Better Paintings
Some of the scientific evidence for Hockney’s theory
What’s the difference between a camera obscura and a camera lucida?
The short answer: A camera lucida, like the LUCY or LUCID-Art, is a device used to reflect a large image over your drawing surface, so you can sketch out the subject.A camera obscura is a device that projects an image onto a screen to help you with perspective, tonal rendering, composition, handling of light, and getting a classic ‘Vermeer look’ to your paintings. The camera obscura can also be very useful for photographers.
The next video gives a more detailed answer with images and diagrams.