From: Jeffrey D. Mathias (jeffrey.d.mathias@worldnet.att.net)
Date: 02/17/00-04:28:58 PM Z
Coating technique can typically require about 3.6 ml of coating mixture
for a typical paper to meet the threshold necessary for an area of 100
square inches. 100 square inches is the area of an 8x10 negative with
about a half inch boarder all around. (Do note that this amount can
vary, 4.3ml and 3.1ml are not unusual for other papers) Half of this
mixture, or 1.8 ml, is a metal solution the other half sensitizer.
With the same paper and technique it was found that Ammonium Ferric
Oxalate (AFO, the Printing Out Process) had a threshold of about 35 and
Ferric Oxalate (FO, the Developing Out Process) had a threshold of about
23 (for a quality FO powder). The associated metal solutions for each
type of sensitizer would be as follows:
++++++++
for AFO:
Li2PdCl4 mixed as a 21.43% solution.
K2PdCl4 made as a 26.7% solution.
or
K2PtCl4 made as a 33.9% solution.
-
The amount of metal salt used is:
145 g/l PdCl2 or
339 g/l K2PtCl4
++++++++
For FO:
Li2PdCl4 mixed as a 12.5% solution.
K2PdCl4 made as a 15.5%% solution.
or
K2PtCl4 made as a 19.7% solution.
-
The amount of metal salt used is:
84.2 g/l PdCl2 or
197 g/l K2PtCl4
++++++++
For the 8x10 print, the amount of metal salt required would be:
For AFO:
0.26 grams PdCl2 or
0.61 grams K2PtCl4
For: FO:
0.15 grams PdCl2 or
0.35 gram K2PdCl4
Do note that Ferric Oxalate (DOP) will produce a print using about 57%
of the metals needed for an AFO (POP) print. Note also that a palladium
print will require about 43% less metal salt than the platinum print.
Do remember that other less expensive materials are also included but
not represented here. Bottom line for the cheapest print, use FO (DOP)
and PdCl4 (if it is less than twice the price of K2PtCl4).
-- Jeffrey D. Mathias http://home.att.net/~jeffrey.d.mathias/
This archive was generated by hypermail 2b29 : 04/24/00-04:37:10 PM Z CST