From: Jeffrey D. Mathias (jeffrey.d.mathias@worldnet.att.net)
Date: 05/14/01-07:52:19 AM Z
Philippe Ayral wrote:
> Yesterday night I prepared some more Oxalate Potassium developer to
> replenish the one I use,
> so I dissolved 300g of Potassium Oxalate in 1000 ml of demineralized hot
> water (the one in supermarket).
> I already used that Potassium Oxalate stock to prepare the developer I
> use for months now.
> Everything was OK and the solution absolutely transparent but this
> morning, when I wanted to store the bottle, all the stuff is
> crystallized at the bottom of the bottle.
> What is the problem ?
> Is there a way to put back in solution and to keep it?
What is the storage temperature?
It is also a good idea to use amber or brown bottles as used developer
likely contains light sensitive material.
I assume that you have crystallization in the unused solution.
I usually mix about the same as you and have seen some crystallization,
but not much, and certainly not enough to think it was substantially
weakened.
If it is only a little, add some more water.
If it is a lot, then consider it may be contaminated and make a new
batch.
If you have crystallization in the used solution, this can be considered
normal.
Get rid of the crystals by decanting. (let sit, slowly pour only liquid
into a tray or another bottle, clean out the solid material and discard
properly, return the poured liquid back.)
If the solution has been used for a large amount of coating (even with
replenishment, and esspecially if exposed to light), consider discarding
and starting with a fresh solution. Used solution can also contain
exposed material which could cause fogging (in the case of heavily used
solutions).
-- Jeffrey D. Mathias http://home.att.net/~jeffrey.d.mathias/
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