[alt-photo] Re: platinum

[Marek Matusz]

Sounds about right, I never ran the acid bath till exhaustion. as far as washin I fill the bathtub with a couple of inches of water and wash the sheets for a whie an hour or half an hour or two if I forget, then drain the water and repeat that. It might be too much, but I got these washing habits from B&W darkroom. Never too much washing.. Marek
 > From: alt.list at albertonovo.it
> To: alt-photo-process-list at lists.altphotolist.org
> Date: Sat, 16 Feb 2013 09:51:35 +0100
> Subject: [alt-photo] Re: platinum
> 
> > Muriatic acid is 37% here in the US and is very inexpensive. It can be found
> > at many hardware stores and home care centers such as Lowes and Home Depot
> > to name a couple.
> 
> Thank you, Don. 
> 
> So, 40 cc/L of 37% HCl (d=1.186 kg/dm3) is about 40*1.186*0.37 = 17.55 g/L.
> If I have to use 10%, d=1.05, that become 17.55/0.1/1.05 = 167 cc/L.
> So written, it seems a fairly high amount. But... 
> 
> Further math for calcium carbonate content accordingly with ISO 9706 (at 
> least 2%):
> 1 sheet (56x76 cm) of 300 g/m2 paper has a CaCO3 content of
> 0.56*0.76*2/100 = 2.55 g 
> 
> 1 g of CaCO3 is neutralized by 36.456/50 = 0.7293 g of HCl.
> This last is in 0.7293/0.37/1.186 = 1.662 cc of HCl 37% 
> 
> The CaCO3 of 1 sheet of paper as above is neutralized by (at least)
> 2.55*1.662 = 4.243973565 cc 
> 
> Finally, 10 sheets will require about (at least...) 45 cc of 37% HCl.
> I'd say that the amount used by Marek (2 L water plus 80 cc HCL for 6-10 
> sheets) is about double than required, but he surely removed all the buffer 
> from his papers. 
> 
> Alberto 
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> Alberto
> www.facebook.com/alberto.novo.1
> www.grupponamias.com
> www.alternativephotography.com/wp/photographers/rodolfo-namias-group 
> 
> 
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