| Very interesting!
Does anyone have any data for washing PT/PD prints? I'm using Permawash to clear and then hand washing — filling a tray then dumping it.
If I can conserve on water, I would like to do so.
Best Wishes,
Mark Nelson
On Aug 8, 2008, at 9:40:53 PM, "Ryuji Suzuki" <rs@silvergrain.org> wrote: What matters is whether there is high enough flow of water in
contact with the emulsion side. However, prints floating on
the surface (even if face down), or print sticking to the
bottom (even if face up), is probably not as efficient as
complete immersion and free flow of water on both sides.
When following instructions of old washers, or consulting old
textbooks, you may see very long washing time, such as 30-60
minutes wash in running water. You might want to adapt more
modern practice in that case.
I have run some tests for residual fixer level with fiber
based prints, using non-hardening rapid fixers and washing
aids. I can meet and exceed the current ISO archival standard
for residual thiosulfate level with much shorter washing
time. Indeed, I could easily meet the standard by a few runs
of fill-and-dump sequenses in a tray, using far less water
than otherwise required by "archival washers."
I have written a fill-and-dump washing recommentation for
prints, similar to that for film washing recommended by
Ilford. The instruction is for Clearfix and Clearwash, but you
can use any generic sulfite-based washing aid. In fact, you
can just use plain 2% sodium sulfite, if you prefer.
Another advantage of washing aid is that it allows efficient
washing with colder water. Although standard instruction
recommends 13C or 55F or higher, in some of my tests, using
Boston's cold winter water at 5C, I could easily meet and
exceed the standard, and I no longer use hot water and a
temperature regulator to adjust the washing water temp for
prints, since hot tap water has environmental load about 30x
that of cold tap water (depending on the heating system, but
the factor of 30 came from a calculation using gas).
Incidentally, I've seen that bottled waters have environmental
load of about 500x the tap water, based on the report I used.
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