[pure-silver] Re: what causes pinholes in emulsion?
- From: Jean-David Beyer <jeandavid8@xxxxxxxxxxx>
- To: pure-silver@xxxxxxxxxxxxx
- Date: Fri, 20 Feb 2009 18:14:50 -0500
Shannon Stoney wrote:
I live in the tropics sometimes. It's tropical in summer here. I think I
processed that film in the winter, though, when it wasn't all that hot
in Houston. I always use developer at 70 degrees or so, but I don't
always check the temperature of the stop.
There seem to be a lot of "old wive's tales" out there about this.
Modern films can probably be processed up to about 100F. Likewise, while I
manage to process my films at 75F, I was not always able to do so.
Nevertheless, never any pinholes. I now use a Jobo CPE2 and most of the
year, I use tempered water for washing the film. In the hottest weather, I
put artificial ice in the water bath until it is just below the temperature
I want, and then remove it. I watch the thermometer to see if I need to
replace the ice, but I have never actually had to do that.
While old (pre WW-II films) films needed more careful control of
temperatures, now days you really do not need to be so careful, and a
several degree difference between the bath temperatures should not matter
much (other than the developer, where you will get confused if you do not
always use the same temperature).
While I always use SB-5 as stop bath for negatives, some people like to use
plain water. I suggest if you want to do that to put some sodium sulfate in
there (the same amount as required in SB-5) so that you do not take the film
from a bath high in salts (mainly sodium sulfite) into one with none, and
then back into one with a lot more sulfite, the fixer. That kind of shocking
may not be so good for the film. But here, too, the modern hardened films
can withstand much more abuse than the old ones that needed processing
around 65F. But there should not be any more of that left anymore.
--
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