From: Richard Knoppow (dickburk@ix.netcom.com)
Date: 07/23/02-06:27:55 PM Z
At 12:57 PM 07/23/2002 -0500, you wrote:
>(I just love the internet...no sooner asked than given)
>Philippe,
> This is what Clerc says under #832, Dye toning: "The mordanting can be
>carried out by the formation of silver iodide and cuprous iodide using the
>intensifying bath described in #687, due to G. Zelger, 1924." Does this
>help?
> Thank you so much for looking into this.
>Chris
>----- Original Message -----
>From: "Philippe Monnoyer" <philippe.monnoyer@skynet.be>
>To: <alt-photo-process-l@sask.usask.ca>
>Sent: Tuesday, July 23, 2002 12:52 PM
>Subject: Re: Clerc's no. 687
>
>
>> Christina,
>>
>> I have the original version in french of Clerc's book.
>> #687 is about washing.
>> What kind of intensifying bath are you refering to ?
>> In Clerc's book, we have:
>> Intensification:
>> - for Latent Image
>> - for Negs
>> - by silver deposition
>> - localised
>> - intensive
>> - optical
>> - by powder
>> - of prints
>> - of carbon prints
>>
>> Make your choice.
>> I don't know what you're looking for.
>>
>> Philippe
>> Belgium
>> > Unfortnately, I am in Minnesota right now with no access to a library
>that
>> > has technical photo books. Does anyone on the list have Clerc's
>> > Photographic Theory and Practice who can give me the info in #687? I am
>> > looking for what is said about an intensifying bath (still on this
>> > mordancage quest).
>> > Chris
>> >
>> >
>>
>
Evidently you are referring to the forth edition of Cler published by
Focal Press. I have the English translations of both the first and second
editions and in both paragraph 687 refers to transfer printing.
In the forth edition is describes a copper intensifier, presumably, this
is what you want.
The bleach is given as:
Solution A
Copper Sulfate, crystalline 8.0 grams
Acetic Acid, glacial 28.0 ml
Water to make 500.0 ml
Solution B
Potassium Iodide 5.0 grams
Ammonia, 0.880 sg 50.0 ml
Water to make 250.0 ml
Add A to B for use and allow to cool completely.
The mixed solution should be clear blue and slightly acid. If it is not
add Acetic acid until blue litmus paper is turned faintly red.
The solution will keep indefinitely.
Bleach the negative until the image becomes entirely yellow.
Wash thoroughly.
Blacken in a solution containing 0.25% of silver nitrate to which about
1% of Sodium Acetate has been added (to prevent the copper nitrate formed
during the reaction from attacking the silver). Before treatment with
Silver nitrate the negative may be immersed in a saturated solution of
alum, so preventing combination of silver nitrate with the gelatin.
The Silver salts, other than silver iodide (chloride precipitated in the
gelatin due to the sue of ordinary water and silver nitrate combined with
the gelatin), are removed by immersion for about two minute in a bath
containing about 1% ammonia, which has no effect on the silver iodide.
The process is competed by reducing the silver iodide to the metallic
state by means of a solution of sodium hydrosulfite containing a little
sodium bisulfite, or be means of an Amidol developer made alkaline with
sodium carbonate.
---- Richard Knoppow Los Angeles, CA, USA dickburk@ix.netcom.com
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