On Mon, 17 Oct 2005, Fabiano Busdraghi wrote:
> the only things I don't like is the precipitate that forms in the bottle. I
> adds solution C really slowly (30' to add 33ml of c solution to 66 of a+b).
> after more or less 25ml the solution start to precipitate. I wait two days
> and then I filter all this green precipitate. the solution is light green,
> and if I don't filter it I have I grainy and inconsistent result. I don't
> like the precipitate cause I say to my self that I'm loosing some salt that
> could be used to increase dmax...
I've puzzled over this report, Fabiano, and -- aside from awe at your
precision (makes me feel like Jackson Pollack) -- I can only suppose VDB
is something like gum, in that there are MORE VARIABLES than we know.
I admit I never measured VDB emulsion -- had it in an 8 ounce (ca 250
ml) dropper bottle and would drop the contents of 2 or 3 or however many
of the looong droppers at the edge of the paper and spread with a damp
foam brush. Still, I would have noticed graininess... And it was months
before a precipitate was visible in the bottle. Maybe the chemicals are
different here & there? (I always used tech grade.) Or the distilled
water?
Or the air?
Judy
Received on Wed Oct 19 00:57:22 2005
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