From: Christina Z. Anderson (zphoto@montana.net)
Date: 07/15/03-05:59:22 AM Z
Kate,
Hey, don't even blush! We're all in this together!
OK, let's recap.
1. The original point of doing the test, for me anyway, was to prove
or disprove the assertion of one author that a justifiable clear (*if*you
*don't* have the chemicals) is the sun. I could not believe this was
true--that sun would do this. It was not to prove its usefulness as a tool
for us today.
2. My results found that after a couple hours in bright sunlight, the
potassium did completely bleach/clear from the borders, the ammonium not
so--a bit of a dif but still there. I do think, after Katharine's testing
and Kate's addition, below, this is due to the saturation of ammonium
dichromate and ensuant greater exposure, but that as Katharine has proven
both trivalent dichromates bleach equally if exposures relate.
3. The original author was proven to be correct, but ******very******
impractical :)
Meanwhile, I am really bummed. I had my digital scale in a padded box,
which dropped from a height of 5 feet. Now when I try to weigh something it
goes immediately to HI so something is jammed. So as far as scientifically
doing this test with equal, let's say, 5%-10% dilutions, it's a no go. I
could do drops of both saturated and then dilute with drops to approximate,
but I guess I am looking at having to buy another scale unless someone on
the list knows what I can do about a jammed scale :(.
Chris
----- Original Message -----
From: "Kate Mahoney" <kateb@paradise.net.nz>
To: <alt-photo-process-l@sask.usask.ca>
Sent: Tuesday, July 15, 2003 2:02 AM
Subject: Re: GUM TESTING
> Ummm....maybe i should have read all the mail from today before writing
> (blush blush)
> Kate
> ----- Original Message -----
> From: "Kate Mahoney" <kateb@paradise.net.nz>
> To: <alt-photo-process-l@sask.usask.ca>
> Sent: Tuesday, July 15, 2003 6:46 PM
> Subject: Re: GUM TESTING
>
>
> > Hi Christina, you will probably find that the reason that the amm di
> stains
> > more than the pot di is that you get a more saturated solution with amm
> di -
> > more chemical in the mix, therefore more staining!
> >
> > Kate Mahoney (New Zealand)
> > ----- Original Message -----
> > From: "Christina Z. Anderson" <zphoto@montana.net>
> > To: <alt-photo-process-l@sask.usask.ca>
> > Sent: Tuesday, July 15, 2003 1:16 AM
> > Subject: Re: GUM TESTING
> >
> >
> > > Good morning Katharine!
> > >
> > > Yes, this is why I even tried it in the first place, because as I had
> said
> > > when I originally posted it, if dichromate is sensitive to sun, why
> would
> > it
> > > then bleach OUT in the sun?? I only came across that method in one
> book,
> > > and most of the other tidbits I've picked up I've come across numerous
> > > times.
> > >
> > > Anyway, the prints I used were 8x10 one layer exposures (full prints)
> that
> > I
> > > had developed out, dried, but not cleared. These were done
> presensitizing
> > > the paper with saturated solutions of the two dichromates, and then
> > painting
> > > the pigment/gum/no sensitizer on top of the dried sensitized paper.
> Thus
> > I
> > > had a good border of dichromate with no pigment on top. I was
> observing
> > > just the dichromate stain in the borders of the prints. Every time in
> > > comparison between ammonium and potassium dichromate that border stain
> > (and
> > > it literally is a dichromate stain, no pigment) is darker in ammonium
> than
> > > in potassium. Thus the ammonium has more ways to go, which is why I
> > covered
> > > up half the print to see the difference in bleaching. The potassium
did
> > > bleach out, the ammonium did lighten but was not entirely gone.
> > >
> >
> >
> >
> >
>
>
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