Letter: Photography in the Middle Ages

Sir: In her claim (report, 8 March) that the Turin Shroud image was made using a camera obscura, I think that Ms Rye is making the error of assuming that because optics and light-sensitive materials were known in the Middle Ages their combination to produce the elements of photography must therefore have also been known.

If this technology was known, why use it only to make a forgery? The next obvious step would have followed: to use the negative images as subjects and so produce positive pictures as rudimentary photographs. Where are the pictures of palaces, gardens etc, from these centuries, even as negative images? Or even the historical references to such images? It is difficult to imagine how such know-how, with all its potential, if it really had existed, could ever have been lost.

R D Mannix, FRCS

Bebington, Merseyside