Mike Robinson's albumenizing and sensitizing description (May 30) is quite
accurate. Floating is the tried and true method. For a truly glossy albumen
paper, brush sensitizing is prone to bubbles and streaks, unless the albumen
is pre-hardened.
For a higher gloss, float twice and hang the paper "upside down" after the
second floating. (The second floating must be relatively short to prevent
dissolving the first coat.) The best coating is done when the humidity is
low. If the paper takes too long to dry, the albumen tends to sink in.
The density range of a negative to print fully on albumen paper (or a salted
paper) is about 2.20 to 2.30, as mentioned. That is with plain 10-15% silver
nitrate sensitizer. Some more complicated sensitizers will increase the
paper's contrast a bit, requiring a negative of only about 2.00 to 2.10
density range. Dropping the ammonium chloride concentration in the albumen to
about 0.5% (from the normal 3-4%) will further increase the paper's contrast
a bit.
By comparison, gelatine chloride printing-out paper (ie. Centennial) requires
a negative of about 1.80 density range for a full-scaled print. This density
range is about the same as that required for platinum with no contrast
increase.
It is difficult to state precise figures for the required negative density
range for any of these papers, as the highlight contrast of each of them is
rather low, and it is difficult to know whether to look for paper white or
highest discernable tonal separation.
The shadow and mid tones on the silver print-out papers and the platinum
papers have relatively high contrast. Hence the feeling of openness and
brilliance in a silver print-out or platinum paper.
By comparison, a DOP like Ilford Multigrade FB with a "00" filter also
requires a negative of about 1.80 density range to print fully, but its
characteristic curve is quite linear. A silver print-out paper or a platinum
paper will represent the same negative with quite open mid-tones and shadows
(higher contrst), but soft highlights. That's why, side by side, a DOP will
frequently look weighted down compared to a silver POP or a platinum print,
even though they are representing the same negative. It's not merely the
color or the paper surface that's the difference, its the manner in which the
shape of the characteristic curve renders the tonal values in each part of
the negative's scale. Even in reproduction, you can tell the difference.
The relatively low highlight contrast in silver print-out papers and in
platinum papers, dictates the use of long scale, linear negative materials.
Because the printing paper will soften the highlights, one whould want to
avoid making negatives with highlights placed anywhere near a negative
material's shoulder. There are very few panchromatic films which can remain
linear over the density range required of these contact processes. The two
best appear to be Ilford FP4+ and Agfa P330p. (But this should be a different
subject.)
Finally, yes, our address is:
Chicago Albumen Works
PO Box 805
Front Street
Housatonic, MA 01236
tel: (413)274-6901
fax: (413)274-6934
Regards,
Doug Munson