Re: Eliminating CaCO3 in buffer in "achival" watercolor papers
The Na4EDTA way seems interesting, since I have plenty of that on hand...
12 Ağustos 2008, Salı, 9:11 pm tarihinde, Ryuji Suzuki yazmış:
> In order to wash out calcium, I suggest an alkaline solution
> of potassium sodium tartrate, an alkaline solution of
> potassium sodium saccharate, an alkaline solution of sodium
> gluconate or Na4EDTA solution. These would be my first
> choice. Besides, though less effectively, you could use an
> alkaline solution of sodium citrate.
> As a starting point, I'd suggest 1% of any of the above agent
> and 1% sodium hydroxide, and soak the paper in the solution
> with intermittent agitation until you find the paper has lost
> the calcium salt, as determined by test prints or whatever
> means you prefer. Na4EDTA does not need additional NaOH and it
> may be effective at an even lower concentration. However, EDTA
> is not biodegradable (and in some areas of Germany and perhaps
> other areas, EDTA pollution is a problem).
> Once you treat the paper, you may wish to rinse off the
> chelating agent and also neutralize the paper to the acidic
> side. I suggest to use a dilute solution of acetic acid for this.