Re: Ammonium/Potassium Dichromate? in Reversal Bleach, was Re:


Judy Seigel (jseigel@panix.com)
Sun, 07 Mar 1999 23:33:52 -0500 (EST)


 
On Sun, 7 Mar 1999, garimo wrote:

> >Yes, ammonium dichromate will work fine in the reversal bleach, you just
> >need less of it. One substitution rule that I remember off hand is for
> >every 100 parts of potassium dichromate substitute 85 parts of ammonium.
> >
> >
> >Sandy King
>
> I'll do it! thank you,
> garimo

The problem (one of them) is that e-mail ruins us -- the exchange is so
instant that if we're a day later we feel neglectful (or neglected). When
I got back on tonight, it was a whole new movie. Do you guys stay on all
day? I realize it *IS* GRIPPING, but you have to eat and so forth...

Anyway, I have used ammonium dichromate in formulas calling for potassium
dichromate because that was what I had at school, or even at home when
I had a percent solution mixed up & didn't want to be bothered mixing
another. As far as I could tell there was no difference. These formulas
(Farmers' reducer, a bromoil bleach, and like that) were not however
*precision* formulas, but stuff you guaged by eye... whether there would
be a difference in a formula like Liam's bleach, I don't know. But somehow
I doubt it.

I've also done it the other way around, by the way, -- used potassium
instead of the called-for ammonium. Same difference.

I didn't think to change the amounts as Sandy suggests (didn't know to),
but the parameters are loose enough that again I doubt it matters. Liam,
isn't that bleach re-used? And mixed with tap water? And how old is your
dichromate? I'm finishing up a 20-year old bottle. Surely there are
already loose lines there....

I mentioned this in another context, but repeat it here -- for all
practical purposes I've found you can do the same gum prints with all the
dichromates. And gum being the most significant, intelligent, compelling
and *sensitive* operation in alt, surely that augurs well.

Garimo -- I hope you're going to let us in on your findings !

Judy



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