From: Jeffrey D. Mathias (jeffrey.d.mathias@worldnet.att.net)
Date: 09/01/01-06:25:21 AM Z
Darryl Baird wrote:
> I often find listings for reagent, technical, or pure grades of
> chemistry available at varying levels of cost. I'm certain reagent
> (ACS?) grade is the best, but do I need this level of quality for
> photo emulsions, or would a technical or "pure" grade be ok?
I believe the "ultra pure" or "pure" grade would be the purest and most
expensive. This would likely be overkill for a photographic process.
I would recommend the "reagent grade" as this will likely pay for itself
in consistency of results. There are two types of reagent grade
available. One has an analysis and the other does not. The analysis
tests a batch for certain impurities and lists them on the label and
costs more. The other is the same, supposedly, without the analysis and
may save some costs.
The "technical grade" may be all right for making formulas that have
been figured out and tested and known to have little influence from the
variability of this grade. This is the lower of these 3 grades. Food
grade can be considered a technical grade which may have impurities but
safe for consumption. If investigating new formulas and optimizing
processes, this grade could introduce inconsistencies that could cause a
lot of aggravation and waste a lot of time.
Additionally it should be important to be careful and clean in every
aspect of a sensitive process.
-- Jeffrey D. Mathias http://home.att.net/~jeffrey.d.mathias/
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