Dick,
So true, so true.
I have observed that long washing of Pt/Pd prints will, in most cases,
weaken the image (loss of depth, substance, and sometimes darkness). I
believe it to be from the paper fibers eventually weakening and
releasing the traped Pt and Pd particals. I have found that washing is
not the only culprit. The entire time in the wet processing must be
considered (this includes clearing). This has become a problem for me
with thicker papers since they seem to require more washing. However, I
think I have found some solutions.
Thin papers such as Biefang 360 can completly clear in about 9 minutes
and wash in about 4 minutes. No problems have been noticed.
Thicker papers such as Crains Busness Card Stock (such as that from B&S)
or Arches Platine seem to require longer clearing and washing times. In
the past, I had to clear for up to an hour. Because of deteriation of
image quality, I experimented and found that a water wash prior to
clearing reduced clearing times by more than half. Also with some
papers such as Arches Platine, some time in hypo remover or equivilent
chemical after the acid helps complete the clearing in less time.
As a general rule, I wash for about one quarter of the clearing time.
The longest times for these thicker papers after a one minute water
rinse are generally 20 minutes total in four or five acid baths and 5
minutes wash. Even with these time I somtimes suspect the the image is
suffering. Sometimes I can get away with less wet time. However, the
time determining factor is the ability to completly clear the print.
Also, when washing, I use fresh tap water, but I only have the smallest
amount of flow and no flow over the print. Since the thicker papers are
in a print washer, gravity does the work. Thin papers are washed in a
tray of fresh tap water, again with no flow.
Another technique is to place the print in a tray of tap water with some
baking soda mixed in for a quick rinse prior to washing. I do still
have a question of what the final PH of the print should be. I suspect
that a slight acidity may prevent atmospheric acids from entering the
paper. Atmospheric acids such as sulpheric and nitric are far more
detrimental to cotton than the phosphoric, hydocloric, or other clearing
solutions used. Perhaps even less washing time may be needed.
I hope this information is helpful. I await any other info. I have
always been conserned with the quality and longevity of my work.
Jeffrey D. Mathias