RalphLambrecht
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Ole
Many thanks, that makes a lot of sense. I filtered the solution right after your post, and will use deionized water in the future. Any idea why this never happend with Kodak's or Ilford's WashAid?
I started to make my own HCA,
Questions:
1. Does the residual HCA harm the print?
2. What is the best way to deal with this?
...
Most of the research was carried out during WW2 when it was discovered that salt (sea) water used to wash prints on board navy ships accelerated the washing process....
Ian
Ole
...sodium sulfite is a toner stop bath...
...
Sulfur dissolves also in sodium sulfite making Thiosulfate. So, a stop
of sulfite works because it ties up available sulfur.
...
Dan, does that mean I'm creating fixer
when trying to stop the toning?
You should be able to get sulfur at a druggist, or a farm supply store.
What happened to the theory that HCA is worse than residual hypo? Maybe that was only for the formulae that contained peroxide.
Thanks Ian
This is not the reason for the thread,
How long can I be saving HCA? I was told
that it oxidized in a matter of hours.
It is that uncertainty with the usual sulfite based
HCAs on the market that has me ready to switch to
Agfa's recommended sodium carbonate based HCA.
A study quoted in a post to rec.photo. darkroom
recently told that sodium sulfite was, IIRC the exact
words, "as good as any other". That is, not any better
than some others. I suspect Agfa's recommended
sodium carbonate is as good as sulfite and it
does not oxidize. Agfa's instructions may
still be on the WWW. Dan
Ralph
If you prefer a low pH level HCA try this
EDTA4Na 12g or DTPA pentasodium salt (solution) 25ml
Sodium sulfite 200g
Sodium bisulfite 6g
Sodium citrate 4g
to make 1000ml stock solution
dilute 1+9 for working solution
Wolfgang Moersch
www.moersch-photochemie.de
I didn't realize that much sodium sulfite would disolve in water. Couldn't you make this more me? I'm just on the other side of town.
I have heard that the working solution is only good for a few hours. If that is the case, how long would the stock solution last?
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