Re: pot. ox.

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From: Jeffrey D. Mathias (jeffrey.d.mathias@worldnet.att.net)
Date: 02/13/01-09:10:09 PM Z


DAVID DISTEFANO wrote:
> ...... after
> the session the developer has a dingy color to it. ...
> Is this normal or would I be better off making new developer for each
> session?

Use the potassium oxalate until fogging is noticed. This can be quite a
long time, even years. Greenish, grayish, or blackish crystals that
eventually build up can be removed by decanting (pouring liquid off the
top). These crystals should not be a problem, but could cause damage to
a fragile paper. It is the build up a sensitizer that becomes
problematic. The addition of some metal salt solution to the developer
actually helps with the consistency of the developer. It only takes a
small amount. A print made with fresh developer can have a slightly
different look and some color difference.

> Another question: for a ziatype before surface drying I let it rest for
> 2 minutes so it can soak into the paper, is this also a good idea in the
> DOP. Arches is the paper that I use.

A general rule of thumb would be to let the coating soak until the
surface looses the glossy look before blowing air (hot or cold).
Blowing too soon could form pudding or a thick build up on the surface
which usually results in a lighter blotch in the print. Leaving the
coating sit too long could result in increased graininess or a loss of
maximum density. It is a good idea to get the coating to the final
dryness or humidity and exposed as soon as practicable. I have noticed
some differences with some materials by waiting an hour, and most all
materials have shown some loss of quality after waiting four hours
(times are from drying to exposing). It is best to not let humid
coatings (like those for z__) sit around once they are ready to expose
as the coatings seem to be more susceptible to havoc when humid.
However it is very important to have an even distribution of humidity in
the coating which careful handling of the drier and perhaps a short wait
(assuming the ambient is at the desired RH) can achieve.

-- 
Jeffrey D. Mathias
http://home.att.net/~jeffrey.d.mathias/


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