> I am writing this in benefit of Mr. Paul Keck of Hawthorne, N.Y. who is
> attempting to produce Autochrome plates. He has been researching this for
> a number of years and is presently stalled due to lack of access to, in
> his words, techically inclined photographic experts.
There are some technically inclined experts in France who are researching
this right now. I don't have the reference to hand but there was an
excellent article in the issue before last (or thereabouts) of History of
Photography. Check it out.
> Here is the problem. What he needs is the knowledge of how
> to manufacture or a source of a panchromatic, extremely fine-grained and
> thin, reversal emulsion.
Although I haven't seen it I'd expect to find this sort of info in E. J.
Wall's Photographic emulsions : their preparation and coating on glass,
celluloid and paper, experimentally and on the large scale. Boston : Am.
Phot. Pub. Co., 1929.
> The emulsion must
> be capable of bonding to the varnish layer protecting the dyed starch
> grains on the glass plate. Any information would be greatly appreciated.
Mr Keck will probably have to "sub" or put a substratum of plain gelatin
onto the plate before coating with the emulsion. There are probably
formulas for this in Wall's book or else see his History of Three-Color
Photography, p. 330.
> Wow! Wouldn't you like to have a handfull of "new" autochrome plates?
Unfortunately I don't think it's as easy as it sounds. One of the older
security guards here told me how he once tried making autochrome plates
when he was still at school. The dyes on the potato starch ran and made
one hell of a mess. The emulsion shouldn't be too much of a problem if you
get the screen right - from my reading of that recent article I think
that's the hard bit.
Good luck,
Philip Jackson
pjackson@nla.gov.au