[pure-silver] Sepia toning & Potassium Bromide & Ira B Current
- From: <C.Breukel@xxxxxxx>
- To: <pure-silver@xxxxxxxxxxxxx>
- Date: Mon, 5 Nov 2007 14:13:09 +0100
FYI
Some weeks ago Richard posted below comment on the list:
>>>>>>>>>>>>>>>>>>>
A curiousity pointed out to me by Ryuji Suzuki is a
patent issued to Ira Current of Ansco for warm tone
developer USP 2,607,686. Current found that adding very
large amounts of Bromide to an active developer made sepia
toned prints cold sepia. This might be worth a try. One of
the developer formulas in the patent is essentially the same
as Dektol. Current added from 20 to 80 grams of Potassium
Bromide to this. From the patent data the development time
will be much increased, perhaps 8 minutes. See the patent
for more data. Most of the literature will lead you to
believe that adding Bromide will result in yellower tones
from sulfiding toners. According to this patent this is not
true _if enough bromide is added_.
>>>>
I picked up the patent, and got the impression (perhaps wrongly) that
when you would use one of the described developers with increasing (big
amounts) of KBr one could obtain warmtone/spia tones out of a regulair
cold tone paper.
I tried on Ilford MG IV RC with below developer:
Metol 5 gr
Sodium sulfite 40 gr
HQ 6 gr
Sodium carbonate 50gr
In 1 liter, with increasing amounts of Kbr from 25, 45 to 64 grams per
liter.
Therewas no change in image tone, nor were the developing times longer
than normal.
Re-reading the patent I think it was more wishfull thinking on my side.
Maybe I'll re-try on Kentmere Kentona, and than tone with a polysulphide
toner afterwards,
Best,
Cor
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