This immediately raises the question of what sort of optical system Leonardo
might have used. I strongly suspect camera obscures in his day simply
weren't up to forming life size images with sufficient illumination at the
focal plane. Pinhole cameras might be worth considering with other emulsions
but with the dark reaction occurring in dichromated colloids after about a
week they're probably out of the question.
On the other hand, if I remember correctly the colour of the shroud seems
vaguely right and dichromated albumen seems so simple and intuitive that you
wouldn't have to be Leonardo to arrive at a workable process: grind up some
chromite ore; mix with albumen (this was, after all, standard procedure in
Foto temporarily yours,
Philip Jackson
pjackson@nla.gov.au
hello Philip ,
Yes I share Your Skepticism however it does make a loverly story published
in the Daily Mail of the 15/16th Aug 1994 the authors did show practical
evidence that seemed to back their story.I have meant to purchase the book
"The Turin Shroud " but have not got around to it yet ,the publisher is
Bloomsbury Press,for those of you who may be interested .It seems one vital
constituent to the emulsion was urine I don't quite now how to take that !
cheers pete :--))