My last organic chemistry course was over 30 years ago so maybe the chemist
in the group should jump in here but I understand that EDTA is a
sequestering agent which I assume retards the oxidizing of the developer.
Some of the premixed PMKs come with EDTA already in the developer otherwise
add 5gm/L to the A solution. I've use PMK with and without EDTA and I think
it makes a difference but at the time I did not have a densitometer so I
could not measure the difference. If you use Photoflo as a wetting agent
after processing it will cause uneven staining on the next films processed
unless removed completely. I have just completed film and developer tests
on TMX, TMY, and TMZ using Xtol, TMax RS, Rodinal, and PMK. I had hoped to
find a developer to use with TMax films other than Pyro because it is a pain
in the rear to use. After 3 months, no telling how many rolls of film and a
ton of paper I'm still using PMK the only developer that comes close to
giving a print with the feeling of a pryo developed negative is Rodinal.
ken hatch
http://home.swbell.net/khatch1
-----Original Message-----
From: Carl Weese <cjweese@wtco.net>
To: Ken Hatch <khatch1@swbell.net>
Cc: Herold Faulkner <faulkner@redshift.com>; SCHRAMMR@WLSVAX.WVNET.EDU
<SCHRAMMR@WLSVAX.WVNET.EDU>; alt-photo-process-l@skyway.usask.ca
<alt-photo-process-l@skyway.usask.ca>
Date: Tuesday, January 13, 1998 8:38 AM
Subject: Re: Pyro
>Ken,
>
><< You did not say, did you add EDTA to your stock? If
>not you should also add EDTA if you are using a Jobo.>>
>
>Could you elaborate on this, please? I'm specifically looking for tips
>on getting pyro to work well in Jobo Expert Drums, any experience you
>can share will be appreciated. What does the EDTA accomplish in this
>connection?
>
>---Carl
>Carl Weese
>Contributing Editor
>_PHOTO Techniques_ magazine
>
>