From: Sandy King (sanking@clemson.edu)
Date: 02/23/02-11:27:11 PM Z
Judy Seigel wrote:
>
>However, that said, I never heard the one about adding dichromate to the
>wash water.
Judy, just for clarification, adding dichromate to the wash water is
the contrast control method for VDB described by James. He does not
discuss adding dichromate to the sensitizer. I have speculated in an
earlier message that his recommendation to add dichromate to the wash
water may be a carry-over from procedures that work with kallitype
based on ferric oxalate. With ferric oxalate kallitye adding
dichromate to the developer is indeed a very effective way to
increase contrast.
Sandy King
> As for why dichromate in emulsion changed contrast here & not
>in South Carolina, I don't have a clue. I'd assume some variable in
>procedure... or water, or chemicals... I didn't like the visual effect of
>the dichromate & didn't pursue it, but maybe you want to try it in still
>water & see if it does anything there.
>
>best,
>
>Judy
>
>
>> Then again I'm still just learing the art of non-silver. :) You all are an
>> incredible help!
>>
>> -dina
>>
>>
>> >From: Sandy King <sanking@clemson.edu>
>> >Reply-To: alt-photo-process-l@sask.usask.ca
>> >To: alt-photo-process-l@sask.usask.ca
>> >Subject: VDB Contrast
>> >Date: Sat, 23 Feb 2002 18:12:51 -0500
>> >
>> >Judy,
>> >
>> >I appear to have lost your last message on this but remember the content.
>> >
>> >
>> >I have no idea why you got greater contrast by adding dichromate to
>> >the sensitizer when I did not. Perhaps one of us is absolutely wrong,
>> >or perhaps we used different materials which changed the results. My
>> >tests were made with fresh VDB classic solution, all mixed with
>> >distilled water, potassium dichromate mixed with distilled water, on
>> >Fabriano Uno, Fabriano Artististico, and Arches Aquarelle. No change
>> >of contrast with any of these papers, just a drastic reduction in
>> >printing speed.
>> >
>> >If others have tried this with VDB it would be interesting to hear of
>> >your results. However, for this type of test one really does need to
>> >use a step table or densitometer to evaluate results.
>> >
>> >Sandy King
>> >
>>
>>
>>
>>
>> _________________________________________________________________
>> Chat with friends online, try MSN Messenger: http://messenger.msn.com
>>
>>
--
This archive was generated by hypermail 2b30 : 03/08/02-09:45:22 AM Z CST