U of S | Mailing List Archive | alt-photo-process-l | Re: Eliminating CaCO3 in buffer in "achival" watercolor papers

Re: Eliminating CaCO3 in buffer in "achival" watercolor papers

I've just read somewhere that calcium acetate (the salt of calcium
carbonate with acetic acid) is also quite soluble. So, I may try a mild
solution of acetic acid instead of HCl too...


12 Ağustos 2008, Salı, 1:29 pm tarihinde, Loris Medici yazmış:
> Thanks Diana,
> I also thought about citric acid but the product is insoluble Calcium
> Citrate (a food additive), thus, it remains in the paper. I'd prefer
> something that totally leaves the paper. Calcium citrate may interfere
> with the process I intend to use - maybe that's why you didn't get perfect
> results...
> Thanks again,
> Loris.
> 12 Ağustos 2008, Salı, 9:16 am tarihinde, dhbloomfield@bellsouth.net
> yazmış:
>> Hi Loris,
>> Not a chemist here, but I also had a horrible time trying to soak
>> Fabriano
>> in oxalic acid, specifically in preparation for pt/pd printing. Seems
>> like I had to be extremely precise with everything; otherwise it was a
>> disaster. I could never get it consistently even (the soaking, the
>> amount I used, or something). Anyway, something came up about this once
>> in
>> a conversation with Mike Ware. He said that he thought oxalic acid was
>> the wrong way to go, and he believed citric acid would be a much better
>> choice-- and gave all the reasons why. That was some time ago, but if I
>> can find that email, I'll forward it on. So I did try the citric acid,
>> and it worked much better, though I never got an idea of the right
>> amount
>> to use, how long to soak, etc-- so it was never perfect (though 100
>> times
>> better than the oxalic acid soak).  I got busy and on to something else
>> and never continued with it. or followed up about exact amounts, etc.,
>> but
>> it did work.