[pure-silver] Re: print washer
- From: Myron Gochnauer <goch@xxxxxx>
- To: pure-silver@xxxxxxxxxxxxx
- Date: Thu, 20 May 2010 10:16:35 -0300
I'm pretty sure I did HT-2 tests of a Paterson "rocking" 8x10 washer many years
ago.
Unfortunately, I don't have any record of my results, but I am dead certain
that I achieved results that were in the archival range --- to the extent that
the HT-2 test can show such a thing.
There were and are two concerns about the washer:
1) Dead spots with little or not water exchange
2) Insufficient flow rate to achieve archival results in a reasonable time
These are easily remedied by intervening in the wash process.
To the best of my recollection this is the procedure I used (or at least what I
would start with now):
1) Proper rapid fixing, no hardener
2) Hypo clearing
3) Pre-washing (a minute or two)
4) When all prints are in the washer, adjust water flow to achieve good rocking
of the basket, but not overflowing the washer.
5) At 10 minutes, take the print basket out and dump the washer. Refill
(quickly) and reinsert the prints.
6) Repeat the complete dump and refill at 20-25 minutes into the wash, and once
more at around 40-45 minutes.
7) Every once in a while lift and lower the print-holding basket two or three
times. (Pull it most or all of the way up.)
8) Finish at 60 minutes unless you want to let the prints soak --- in spite of
dire warnings, I have not seen any detriment until the soak extended to
something like 24 hours (and after a few days the emulsion starts floating off).
The complete dumps unsure that the level of fixer in the wash water is
sufficiently low and uniform, and the up-and-down agitation helps minimize dead
areas near the prints.
All of this is probably overkill. If you can get ahold of the chemicals to
make HT-2, you can experiment to see what you really need in the way of water
exchanges and time.
You might discover that dump-and-fill three or four times in an hour, plus some
level of up-and-down agitation, does a surprisingly good job, especially if you
use a rapid fix technique.
The Paterson washer was included in tests done by David Vestal back in the
early 1980's. I probably still have the report somewhere downstairs (along
with Ctein's depressing tests of enlarger lenses).
Myron
On 2010-05-20, at 1:50 AM, Peter Badcock wrote:
> Thanks Jean-David,
>
> That's rather depressing to read. I'd love to see the test
> details/conditions if possible. Were they testing residual fixer levels in
> the paper to a level that is considered archival by today's
> standards/consensus ? In the mean time I'll see what I can do to make it
> shower over the top.
>
> rgds
> Peter
>
> On 20 May 2010 00:11, Jean-David Beyer <jeandavid8@xxxxxxxxxxx> wrote:
>
> When I got my Zone VI print washer, Fred Picker enclosed a test report of
> print washers by a test lab he hired. I assume Zone VI paid for the testing,
> so the Zone VI came out first -- about the same as the East Street print
> washer that was no longer available. The oscillating Patterson tested the
> worst. They found the oscillating feature was of no use and you got
> comparable results with it or without it. They made it work about as well as
> all the others if they built a gizmo that showered the water in the top all
> over the reservoir. But by the time I read that, I had no interest in making
> something like that and besides it was not big enough for 11x14 inch prints.
>
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