RE: Ammonium Dichromate

Do you think that a stonger gum would give me better
range?
--- Loris Medici <loris_medici@mynet.com> wrote:

>
> Trevor, it seems pretty normal that you have
> undissolved AD in your
> bottle. Actually, you "should" have some undissolved
> solid in order to
> guarantee a saturated solution. If I'm right, 60gr
> AD in 150ml water
> should make a 28.5% solution. As water solubility of
> AD is around 25%
> (IIRC, @ room temperature), your solution is a
> saturated one - you can
> use it comfortably, just make sure that you don't
> have solid in your
> coating mixture. IMO, your gum is weak; I've used
> ratios such as 1:1 or
> 1:2 (gum clumps/tears:water) but I never used low
> concentrations such as
> 14.2% (which is the exact concentration of your
> gum)...
>
> Regards,
> Loris.
>
> > -----Original Message-----
> > From: trevor cunningham
> [mailto:tr_cunningham@yahoo.com]
> > Sent: Wednesday, December 29, 2004 11:55 AM
> > To: alt-photo-process-l@sask.usask.ca
> > Subject: Ammonium Dichromate
> >
> >
> > Just finished my first gum! An infrared print of
> my
> > bedroom window (original at:
> >
>
http://www.geocities.com/chalk_jockey/bedwindow.html?1101125921406)
> >
> > Not a lot of contrast, but then I used "burnt
> sienna"
> > with a touch of black (sort of a curry
> brown)...then
> > again, our sunlight is a little hazed out today
> here
> > in Cairo, the local rice farms are burning their
> waste
> > again...you can smell it in the air... another
> > question: Why might my ammonium
> dichromate/distilled
> > water solution be forming crystal lumps in the
> bottom
> > of the bottle (glass, dark brown)? IS this
> normal?
> > Or should I dump and begin anew? My solution is
> 60g
> > dichromate to 150mL of distilled water. Should it
> be
> > stronger? Weaker? Gum is 30g to 180mL.
> >
> > =====
> >
> > "The optimist believes this is the best of all
> possible
> > worlds. The pessimist fears it's true" - J
> Robert Oppenheimer
> >
> http://www.geocities.com/tr_cunningham
>
>
>
>
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>

=====

"The optimist believes this is the best of all possible worlds.
 The pessimist fears it's true" - J Robert Oppenheimer
 
http://www.geocities.com/tr_cunningham

                
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Received on Wed Dec 29 07:42:17 2004