Gary Miller (gmphotos@earthlink.net)
Mon, 08 Mar 1999 07:28:07 -0800
Yes Judy;
Liam's bleach solution is reused until it no longer bleaches. And it is
made up with tap water. My solution has been made up to a final
concentration of sulfuric acid of about 9.2% instead of the called for 10%
and I see no difference. I too think that there is a fudge factor in many
formulas. This bleach solution is a good one for fudging because it is so
obvious when it needs to be replaced, the bleaching process slows way down
or really stops. Then you replace it. But I have run up to 10 8x10 sheets
through it and it was still alive and kicking, although a little tired, just
as I was after processing 10 sheets of lith film.
GM
PS. You mean there is something else out there besides being on line??????
-----Original Message-----
From: Judy Seigel <jseigel@panix.com>
To: alt-photo-process-l@skyway.usask.ca
<alt-photo-process-l@skyway.usask.ca>
Date: Sunday, March 07, 1999 8:37 PM
Subject: Re: Ammonium/Potassium Dichromate? in Reversal Bleach, was Re:
>
>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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