From: Amanda N Bird (anb221@nyu.edu)
Date: 03/26/01-08:00:51 PM Z
----- Original Message -----
From: Judy Seigel <jseigel@panix.com>
Date: Monday, March 26, 2001 7:03 pm
Subject: Re: Clearing Gum Prints
>
>
> On Tue, 27 Mar 2001, Peter Fredrik wrote:
> > > FULLY OXIDIZED..... IF WHATEVER TINGE OF ORANGE REMAINS DOESN'T
> BOTHER> > YOU AESTHETICALLY (and I rather like it), IT WON'T BOTHER
> ANYTHING ELSE.*
> >
> > What's all the shouting about ?
>
> Actually Pete, I'm using a keyboard with a caps lock just under my
> pinkyand it's always going off... usually i go back & retype but
> this time I
> thought what the hey -- because some things seem to go against a
> gradient:and I've never seen a book or article in OUR time that
> didn't end with
> that ritual. (I don't seem to get visible stain myself, maybe my
> one sign
> of grace from on high -- maybe also because my soaks are usually
> long.)Anyway, apologies to all for "shouting" (it's been a
> shoutable week,
> though).
>
> > Your assumption is incorrect .I have over the years sort out
> chemists and put
> > this question to them they have said that given the dilution of
> the sulphuric
> > acid, it should not pose any problems, as long as simple soak of
> a few
> > minutes in clean running water follows the treatment
>
> On the one hand, I quite agree... imagining that such dilute affair
> unlikely to do harm... But, truth to tell, Pete, entre nous, my
> experienceis sometimes chemists speak beyond their area of
> expertise... ? (tho here
> I draw the veil). Conservators seem ..... more conservative perhaps.
>
> > Have you other scientific insight ?
>
> Never enough on hand, though hope springs eternal. But -- and I
> think you
> told this once before, permit me to ask for a refresher: Why the
> sulfuric,which I prefer not to handle (tho I have, I will, I can),
> instead of
> relatively benign sodium sulfite, or even k bisulfate... A half
> teaspoon,no pouring of strong stuff ????
>
> > > I think this a load of nonsnse. If you are doing multi- colour
> print> > controling that green stain gives real problems. Also
> given a bit of care
> > > and common sense this things do not pose any problem to saftey
> .As we have
> > > seen vis a vi the chrome /.dichromate debate in which you took
> a similar
> > > stance ie commen sense rules !
>
> Now here you've got me : WHAT green stain? I've never seen a *green*
> stain in gum printing.... Tho when I cleared some paper "sized" with
> dichromate in gum arabic in a weak sulfuric bath, it did get a bluish
> stain I could never get out. Was a lousy size anyway, so i was
> happy to
> abandon it.... but, again -- *green* stain ???? Stain I've seen was
> alwaysorange.
>
> best,
>
> Judy
>
>
> Speaking of gum prints...
I have been having problems with my coloring. Normally, I use potassium
bichromate and notice that the orange color of the chemical has only a
slight affect on the overall finished color. However, I recently switched
to using ammonium dichromate and have noticed a very strange reaction
with this orange chemical. My colors have been coming out quite different
that one would expect an orange color mixture to produce. I am using
Winsor & Newton water colors. Is this color difference normal when using
the different chemicals? Why is there such a difference when the
chemicals are the same orange hue?
Amanda
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