RE: Ammonium Dichromate

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

                
__________________________________
Do you Yahoo!?
Meet the all-new My Yahoo! - Try it today!
http://my.yahoo.com
 
Received on Wed Dec 29 06:17:18 2004