Re: [Rollei] Film washing technique

["Richard Knoppow" <dickburk >]

- ----- Original Message ----- 
From: "Philippe Tempel" <ptempel2000  >
To: <rollei  
Sent: Friday, May 02, 2003 2:03 PM
Subject: [Rollei] Film washing technique


> I've been using the six water change method in a Jobo
> tank.  Do you guys/gals think this is enough to get
> the fixer off the film?  This came up in B&W Photo III
> class last time and some though that the standard
> 10-15 minute wash combined with a Hypo clearing agent
> is needed.  I just wanna make sure I get no surprises
> 10 to 20 years down the road... ;-)
>
 A standard test for residual hypo is Kodak HT-2
Water, triple distilled        750.0 ml
Acetic Acid, 28%               125.0 ml
Silver Nitrate                   7.5 grams
Water, as above, to make         1.0 liter

This is about two life times supply. Cut by ten and make up
no more than 50 or 100 ml unless you plan to test whole
sheets of paper.

  Test film or paper when wet. Blot the surface and place a
couple of drops of the test solution on a clear area. Wait
about two minutes and rinse off.
  There should be no more than a very slight yellow
discoloration. Any more indicates the presense of excessive
hypo.
  Kodak makes a comparison chart for rough quanitative
measurement of hypo.
  Whole sheet tests are made to determine the uniformity of
washers.
  A more elaborate version of this test "fixes" the stain
with sodium chloride and can be used for densitometer
measurements to determine the hypo content. Quite small
amounts of hypo can be detected this way.
  Measure at an unused area of the film or on a scrap of
paper processed alongh with the prints. The stain from the
test solution is permanent. If not fixed with sodium
chloride it will darken with time.

- ---
Richard Knoppow
Los Angeles, CA, USA
dickburk  

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