rurmonas@senet.com.au
Date: 12/09/02-04:25:31 AM Z
Quoting Sandy King <sanking@clemson.edu>:
> What I would propose as an alternative VDB processing procedure for
> maximum image permanence would be this:
>
>
> 1. Expose the print.
>
> 2. Wash for a couple of minutes to get rid of most of the soluble
> silver halides.
>
> 2. Tone.
>
> 3. Brief rinse.
>
> 3. 2 minutes in clearing bath #1 = 3% citric acid.
>
> 4. Brief rinse.
>
> 4. 2 minutes in clearing bath #2 = 3% citric acid.
>
<--snip-->
Sandy,
The flaw I see with this procedure is the wash at step 2 and the rinses.
>From some simple experiments with FAC it appears that an alkaline
wet processing stage forms a low solubility iron compound. Hence
all wet processing should be neutral/slightly acidic until the iron
has been removed. I would thus propose:
1. Expose
2. Citric wash (two stages)
3. Rinse (The unwanted salts should have been removed in step 2)
3. Tone
4. Wash
5. Fix ...
At this stage I have not looked at how acidic the bath must be remove
the iron salts, hence a 3% solution may be stronger than required.
Richard
--- Richard Urmonas rurmonas@senet.com.au ------------------------------------------------- This mail sent through SE Net Webmail http://webmail.senet.com.au
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