Thanks to the kindness of Judy Seigel in forwarding some of your List
postings, I realise that this hiatus could not have happened at a worse
time. The thread on 'mediaeval photography' interests me greatly from a
photohistorical point of view. Until my communications problem is resolved,
I won't attempt to contribute at length, though I have seen both the BBC TV
programs on this topic. BTW the "ammonium salt" used by Picknett and Prince
to replicate Leonardo, bore a remarkable resemblance to ammonium
dichromate. I would like to ask all you Gumbies and Eggies (we'll leave out
the urine) if anyone knows of the successful use of a dichromated colloid
to record a negative *in a camera*.
I hope in the near future to publish some optical/photochemical
calculations on 'primitive' photographs, but never imagined this piece of
research could be so amusing. Thanks for all your magical contributions.
Meanwhile, may the Shroud remain in the reverential care of the Merciful
Sisters of the Unjustifiable Assumption.
Yours, from the Ninth Circle of Hades (reserved by Dante for the Alchemists)
Mike