From: Richard Knoppow (dickburk@ix.netcom.com)
Date: 08/10/03-02:23:16 PM Z
----- Original Message -----
From: "Eric Nelson" <emanmb@yahoo.com>
To: <alt-photo-process-l@sask.usask.ca>
Sent: Sunday, August 10, 2003 10:04 AM
Subject: Re: The "New" Tri-X
> Both PX and TX have much different development times
> than before, in my practice. However I've not noticed
> any differences between the new and the old or gotten
> any customer comments re:differences once they've been
> printed.
> Eric
>
> --- Jonathon Russell <hylandscot@voyager.net> wrote:
> > What is the general consensus of the group to
> > Kodak's changing Tri-X and
> > Plus-X? Does it behave the same as the "old" tried
> > and true varieties?
> > Forgive me if this has been a topic in the past;
> > just point me in the
> > right direction off list please.
> >
> > Warm Regards,
> >
> > Jonathon Russell
> >
Some, at least, of the difference in developing time is
due to a change in the overcoating rather than the emulsion.
Pretty much all films have a coating of gelatin over the
emulsion to protect it from abrasion. The overcoating
affects the diffusion time of solutions getting into the
emulsion. Kodak has stated it has changed the overcoating on
some of the films.
Plus-X Pan Professional _sheet film_ has been
discontinued. Most of you know that two different emulsions
were sold under both the Plus-X and Tri-X name. The roll
films were medium-toe films for general use, the sheet films
were very long toe emulsions with characteristic curves
which had increasing contrast all along their length. This
characteristic was intended to produce very bright
highlights. Tri-X sheet film is still of this type although
its curve is not as pronounced as Plus-X was.
Both trade names have been in use for many years with
probably several changes in the emulsions sold under them
over that period.
--- Richard Knoppow Los Angeles, CA, USA dickburk@ix.netcom.com
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