Eyck's drawing of Cardinal Albergati reproduced with a concave mirror

Projection of a life-size reproduction of van Eyck's drawing of Cardinal Albergati (right), by a concave mirror (center), onto a screen at a magnification of ~40% (left). Because a digital camera can capture only a limited brightness range, the exposure for this photo was a compromise to keep the drawing at the right from being washed out. This setup was created by Natalie Gakopoulos as part of her senior capstone project in optical engineering (fall 2007). Even though the measured illumination of the drawing was only 12% of noon sunlight, the brightness and sharpness of this projected image were more than sufficient to allow Natalie to easily trace it with the level of accuracy that is exhibited in the van Eyck painting. The sketch Natalie made using this optical setup is below. This is the same optical setup that Stork used for his calculation that he claims found "there is never a sharp focus," from which he concludes it "casts doubt upon this claim [that a projected image was used]." As Natalie's sketch shows, all one needs to do is to project an image at the appropriate magnification to see that Stork's conclusion from his computer calculation of this optical setup is quite obviously wrong.

Category:

Education

Tags:

• camera obscura
• Hockney
• Falco
• Eyck
• Cardinal Albergati
• concave mirror
• camera lucida
• old masters
• drawing
• painting