Re: Everclear

On Fri, 15 Oct 2004, Christina Z. Anderson wrote:

> I am going to wager a bet that the yellowing has to do with alkalinity,
> either of the paper or the water supply. This whole batch I did with
> distilled water, and if after 3 months my sample papers don't turn
> dramatically yellow, I could retest with tap water.

We seem to have enough different experiences with yellowing/non-yellowing
to suggest that more than one factor, probably even a combination of
factors, are operative. But I have an idea that my own experience with
the yellowing was on paper that was not rinsed after the glyoxal bath. At
a certain point I began giving a longer bath (3 minutes) and rinsing
afterwards and I think none of those sheets has yellowed...

(I note here what I found in a series of tests a couple of years ago -- a
glyoxal soak of less than 3 minutes didn't properly harden if it was
rinsed before drying. But a bath of 3 to 5 minutes could be rinsed without
compromising the hardening. I suppose therefore that the glyoxal solution
continued to harden the gelatin while it dried on the paper.)

Judy

I suppose I could also
> test that by adding sodium carbonate to a batch and seeing if the yellowing
> increases dramatically. The paper that I had over the summer that did not
> yellow was Lenox, and the other one was Fabriano, which I know is alkaline
> because Ware's cyano turns lavender on it.
> Chris
>
>>
>> It occurs to me to wonder what the pH of your water is... Because, tho I
>> have seen that yellowing in a bead of gelatin at the edge, that only
>> happened once or twice and yellowing has been very rare otherwise... In
>> fact i've got some paper out on a couple of surfaces in my studio that's
>> been hanging around for a year or two -- unchanged. Since I did see strong
>> discoloration from a couple of alkalis (I remember sodium carbonate in
>> particular) added to the glyoxal, supposedly to strengthen linking of the
>> gelatin, I'm wondering if that could be at work...
>>
>> What's the pH of Everclear?
>>
>> Or maybe it's from being IN the gelatin, not over it???? I've never put
>> the glyoxal in the gelatin...
>>
>> Judy
>>
>
>
Received on Fri Oct 15 21:26:30 2004