From: Sandy King (sanking@clemson.edu)
Date: 01/05/03-08:40:11 PM Z
Ed Buffaloe wrote;
>Note that the ferric citrate/ferric oxalate process that Stevens includes in
>his brown print chapter was originally listed in Cassell's under "sepia
>print."
Yes, but many kallitype/brownprint formulas appear to be far more
complicated than necessary, and in this particular case one wonders
if the formula would not work just as well with only ferric citrate
since development is in water and it is a well known fact that ferric
oxalate will not activate and clear in water without further
additives.
>
>
>To sum up, none of the sources I possess, up to the 1930's, call Arndt &
>Troost's formula (or similar formulas) "Vandyke"--it is referred to as
>brown-line, brown print, sepia, or kallitype. The term "Vandyke" has only
>been applied to Arndt & Troost's process relatively recently, but I haven't
>been able to determine precisely when. At some point "brown print" and
>"Vandyke" became interchangeable, but early on they were totally different
>processes.
It would be interesting to know at what point vandyke and brownprint
became interchangeable. The terms were apparently not interchangeable
in the 30s but had become so by the time Crawford published KOP.
> I haven't been able to find any reference that says that
>"Vandyke" or "brown print" must be a ferric ammonium citrate process.
And I am not saying that either. However, it does appear clear that
from the earliest period there are two broad categories of
silver-iron printing, one based on ferric oxalate that required
special developers, and another based on ferric ammonium citrate (or
fac plus another ferric solution) that could be developed in water
alone. And of the ferric solutions that will develop in water fac is
the most effective, i.e. sensitive, at least according to Stevens'
experiments.
The addition of ferric oxalate to any formula containing ferric
ammonium citrate or ferric citrate that is developed and cleared in
water alone probably has little or no impact on the final image and
can be considered unnecessary complication of the formula. On the
other hand the combination of fac with one of the other ferric
solutions that can be developed in water along (ferric citrate,
sodium ferric citrate and potassium ferric citrate) may change the
nature of the final image by increasing contrast, decreasing
sensitivity and/or giving a higher Dmax.
Sandy King
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