From: Judy Seigel (jseigel@panix.com)
Date: 02/24/03-07:47:16 PM Z
On Mon, 24 Feb 2003, pete wrote:
> My limited experience of it is it stains very badly. This may be because it
> is very strong I think it is possible to get a 60 to 70% saturated solution
> compared to a 20 to 25% with amm and a approx 10 to 15% with pot. You can
> also use chromic acid but this is a real NO NO from a safety point of view.
> I certainly would not sprinkle it on my fish and chips %-<.
>
> Pete
>
> > Steve Bell wrote:
> >>
> >> By the way, a quick question. i read somewhere that sodium dichromate can
> >> be used to make gum prints, has anyone ever done this? does it work? any
> >> notes you can share with us?
> >>
> >
> >
> > It's deliquescent (meaning that it soaks up water and gets all wet and
> > messy) I assume that's the reason no one's ever used it much.
> > kt
Deliquescent is beside the point if you put it in water right away, where
it keeps indefinitely. As for using it... Paul Anderson used sodium
dichromate at 100% saturation -- no wonder he worried about pigment stain
-- and devised a test that guaranteed such low densities of pigment that
even 100% sodium dichromate could be printed.
I've printed with sodium dichromate because someone sent me some & asked
me to try it. I found it, for all practical purposes, the same as the
others at the same percent. And that goes for the difference between am di
& k di too... In my tests, the difference between the two was trifling if
any, when they were used at the same percent. To say that a stronger
percent stains more is.... duh? (Not to mention that a longer soak will
even it all out anyway, or that with our simple instrumentation, AND hand
coating, you're never 100% certain that all other variables were EXACTLY
the same.)
I myself prefer am di because it gives me more flexibility. That is, I
have the stronger sensitizer and then dilute as desired at printing time.
I almost never use the 26% am di undiluted... That way I feel I'm using
the least possible amount of dichromate.
Judy
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