Someone's already done it! Seems my guess about PMK and Ascorbic acid is
correct. I am sure you have seen this already but I just thought I'd pass
it on.
I will make a JOBO version for sale!!!!
--Dick
>Date: Wed, 28 Jan 1998 12:39:32 +0100 (MET)
>From: Cor Breukel <cor@ruly46.medfac.leidenuniv.nl>
>Subject: PMK-Modification against uneven(Oxygen) staining (fwd)
>X-Sender: cor@ruly46
>To: alt-photo-process-l@skyway.usask.ca
>Comments: "alt-photo-process mailing list"
>X-MIME-Autoconverted: from QUOTED-PRINTABLE to 8bit by
internet.roadrunner.com id EAA11699
>
>I take the liberty of reposting a message by Herald Leban, dealing about
>the use of ascorbic acid in PMK...
>
>Cor Breukel
>
>http://ruly70.medfac.leidenuniv.nl/~cor/cor.html
>"The Infrared Gallery"
>http://ruly70.medfac.leidenuniv.nl/~cor/ir-gallery.html
>
>
>---------- Forwarded message ----------
>Date: Tue, 13 Jan 1998 03:37:03 -0500
>From: Harald Leban <HLEBANPHOT@compuserve.com>
>To: Alt-Photo-Process-List <alt-photo-process-l@skyway.usask.ca>,
> Harald Leban <hlebanphot@compuserve.com>
>Subject: PMK-Modification against uneven(Oxygen) staining
>
>Hello alt´s
>
>When I look for the latest correspondences about the pyro-developing it
>seems to me if most of you have equal problems with PMK like myself.
>
>The uneven staining and high base-fog problems in tray and also in
>rotation-developing let me think about the reason-why.
>I think the main problem is the air-oxydation combined with the relatively
>long developing time. To eliminate these facts should clean my problems and
>negatives.
>
>I made two modifikations on Hutching´s PMK:
>
>The first, to slow down the air-oxidation of the working solution, I added
>ascorbic acid as antioxidant to solution A.
>
>The second, to cut the developing times, I concentrated the working
>solution (added more pyro and metol but also a small amount Potassiumbromid
>against fogging to Part A).
>
>Since I used this modifications I never had problems with the results on
>HP5+, FP4+, T-Max 100.
>
>For mid- and large-format this corrections have no bad effects on negatives
>(grain, sharpness etc..)
>
>So try it - and you have some problems less.
>
>When you work with ready to use packs from photographers formulary or
>others you should use only 75% quantity water to make Part A and add the
>ascorbic acid and Potassiumbromid.
>
>If you make it yourself try his:
>
>Rezepture PMK mofdified by H.Leban
>
>
>PartA
>
>800 ml aqua dist.
>20g Sodiumbisulfit, Sodiumhydrogensulfit
>20g Metol
>150g Pyrogallic acid
>10g Ascorbic acid(Vit-C)
>1,5g Potassiumbromid
>2-5g EDTA-Na4
>
>
>Part B
>300g Kodalk, Sodiummetaborat
>5g EDTA-Na4
>in 1l aqua dist.
>
>For normal and N+/N++/N+++ developing use: 1PartA + 2Parts B + 50 Parts
>water
>
>Times for HP5+(at 400 ISO) 22°C(72°F) Rotation-Jobo
>
>N/6,5min
>N+/8min
>N++/9,5min
>
>For normal and N-/N- -/N- - -/N-3 developing use: 1Part A+2PartsB+ 100Parts
>water
>
>
>Times for HP5+ (at 400 ISO) 22°C (72°F) Rotation-Jobo:
>
>N/8min
>N-/6,5min
>N-2/5,5min
>
>
>These are my processing dates to get 8x10" negatives for platinum/palladium
>- maybe you have correct it for your work.
>
>I also process FP4+, T-Max100, Lotus View Classic100 and T-Max400 with best
>results.
>
>If you need a detailed Rezepture sheet and times for other films please
>contact me directly.
>
>
>Greetings from Austria
>
>Harald Leban
>chemist and alt-photographer
>
>hlebanphot@compuserve.com
>
>Platinum prints at: http:\\www.aperture-photo.com (the platinum room)
>
Bostick & Sullivan
PO Box 16639, Santa Fe
NM 87506
505-474-0890 FAX 505-474-2857
<http://www.bostick-sullivan.com>http://www.bostick-sullivan.com