[pure-silver] FW: Sepia toning & Potassium Bromide & Ira B Current
- From: <C.Breukel@xxxxxxx>
- To: <pure-silver@xxxxxxxxxxxxx>
- Date: Tue, 20 Nov 2007 10:35:16 +0100
FYI
About 2 weeks ago I posted below message: I tried to obtain cold sepia tones
with a developer with hughe amounts of potassium bromide (KBr). Mistakenly I
tried it with cold tone paper (Ilford MG IV).
I repeated the experiment with Ilford MG WT FB paper, and toned with a direct
sepia toner (poly sulphide toner, Kodak T-8).
Standard developer: chocolate/warm brown
Developer plus 25 g/l KBr: still quite brown
Developer plus 50 g/l KBr: quite neutral perhaps a hint of cold sepia
Developer plus 75 g/l KBr: quite neutral perhaps a hint of cold sepia
So in principle Ira Currents observation seems to hold true for modern warm
tone papers as well. There is about a 1-1½ stop loss in speed with increasing
KBR, the development time was not longer unlike the description in the paptent.
This was a quick experiment, I guess the concentration of KBr needs carefull
dailing in. I do not see direct use, unless you want to protectivly tone with
polysulphide WT paper without a colour shift,
Best,
Cor
> -----Original Message-----
> From: Breukel, C. (HG)
> Sent: maandag 5 november 2007 14:13
> To: 'pure-silver@xxxxxxxxxxxxx'
> Subject: Sepia toning & Potassium Bromide & Ira B Current
>
>
> 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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