Smieglitz@aol.com
Date: 11/11/01-02:30:38 PM Z
In a message dated 11/11/2001 11:15:20, sanking@clemson.edu wrote:
<<
I do remember that in the remote past I worked with dichromate
solutions mixed with tap water. Solutions mixed with this water would
in fact change color and develop sludge and other residue on the
sides and bottom of the bottle after a few months time, and
eventually turn brown or green.>>
I'd guess that any weaker strength solutions mixed without distilled water or
containing a minor amount of contamination and/or stored partially full would
show deterioration effects to a greater degree than a stronger (e.g.,
saturated), purer solution. IOW, a 3% solution would have a weaker immune
system and be affected by contamination or a specific volume of oxygen in
partially full bottle sooner and to a greater degree (read loss of speed)
than a 10% solution or a saturated one.
Since Sandy no longer has this problem since topping off the bottles and
using distilled water, I'd say that sounds like the way to go if the
solutions are going to sit for awhile at any dilution and knowledge of actual
speed is a concern. (Which it isn't for me since other variables like
humidity and pigment change the outcome more and I usually lack notes and
have forgotten what happened 3 months ago. That initial step wedge print
informs the day for me.)
Joe
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