Those of you with access to suitable libraries or who can get hole of a copy
of this week's British Journal of Photography (20/27 Dec 1995, Vol 142
No.7056) might like to know that there is a 2 page article in it (p24-25)
by Dallas Simpson entitled 'Heavy Metal Magic' giving some preliminary
information on new approaches to the process.
Dallas Simpson builds on the work of Mike Ware (see BJP 13 June 1991 - The
Argyrotype Process) in looking for methods that prevent the deposition of
insoluble ferric hydroxide in the paper - which leads to the common fading
of kallitypes. The absence of oxidising agents (such as nitrate ion,
dichromate or chlorate) enables higher sensitivity to light and the paper
can be exposed by projection (typically 30 mins using a 150 watt slide
projector). Methods using a pure iron sensitiser and an iron/silver
sensitiser are outlined.
(Of particular interest to me was the use of ammoniacal silver tartrate as I
did some experimentation with various related sensitisers a few years ago,
abandoning these on reading Mike Ware's article.)
Sufficient details area given of both the approach and the rationale to make
this a useful source for anyone wanting to experiment with the process.
Peter Marshall
petermarshall@cix.compulink.co.uk