From: Richard Knoppow (dickburk@ix.netcom.com)
Date: 07/20/01-06:51:26 PM Z
At 11:18 AM 07/20/2001 -0600, you wrote:
>Hi:
>
>What film are your using to make your enlarged negatives with? If you are
>using an ortho film try using water instead of stop-bath. I used to do a
>lot of 35mm kodadk ortho for work and it invariably had pinholes if stop
>bath was used. None if plain water was used as a "stop bath".
>
>I don't know if large format ortho's have this problem. I still stop my
>big ortho pinhole negs in water.
>
Pinholes can be caused by effervescence in the stop bath but it depends
on the type of alkali in the developer. Developers using carbonates and
caustics produce carbon dioxide gas, those using Borax or Metaborate
(Kodalk) do not. The effect is fairly rare because it requires that the gas
be generated faster than it can diffuse out of the emulsion.
If you use a water bath make sure you rinse long enough to get the bulk
of the developer out of the film. It may be useful to use a sulfate bath
which will reduce the swelling of the emulsion caused by the developer.
Pinholes caused by outgassing are genuine disruptions in the gelatin.
More often pinholes are tiny clear spots caused by dust on the negative at
the time of exposure or from small bubbles or particles of dirt stuck to
the film in the developer.
>On Fri, 20 Jul 2001, Matthew Hoffman wrote:
>
>>
>> Help! Does anyone have experience repairing pinholes, dust specks, etc., on
>> enlarged negatives? No matter how meticulous I am about preparing negatives
>> (with an anti-static brush and compressed nitrogen) prior to enlarging,
>> doobers invariably appear....usually in big-sky areas, where they're
>> impossible to ignore. I've tried spotting negatives with india ink, but
>> it's hard to control. Even with a fine sable brush, I tend to wind up with
>> ink blobs that are worse than the original defects. Is there a more precise
>> approach?
>> Thanks!
>> -- Matthew
>>
>
>---------------------------------------------------------
>Gordon J. Holtslander Dept. of Biology
>holtsg@duke.usask.ca 112 Science Place
>http://duke.usask.ca/~holtsg University of Saskatchewan
>Tel (306) 966-4433 Saskatoon, Saskatchewan
>Fax (306) 966-4461 Canada S7N 5E2
>---------------------------------------------------------
>
>
---- Richard Knoppow Los Angeles,Ca. dickburk@ix.netcom.com
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