[pure-silver] Re: TMAX grain - developer modification?
- From: "Richard Knoppow" <dickburk@xxxxxxxxxxxxx>
- To: <pure-silver@xxxxxxxxxxxxx>
- Date: Sun, 10 Oct 2004 20:38:56 -0700
----- Original Message -----
From: "Ryuji Suzuki" <rs@xxxxxxxxxxxxxxx>
To: <pure-silver@xxxxxxxxxxxxx>
Sent: Sunday, October 10, 2004 4:32 PM
Subject: [pure-silver] Re: TMAX grain - developer
modification?
> From: "Richard Knoppow" <dickburk@xxxxxxxxxxxxx>
> Subject: [pure-silver] Re: TMAX grain - developer
> modification?
> Date: Sun, 10 Oct 2004 11:53:32 -0700
>
>> Evidently it doesn't suffer from grain clumping as much
>> as some
>> other films, perhaps due to the very hard emulsion which
>> does not
>> allow as much migration of the grains. Grain clumping is
>> caused by
>> high pH developers which soften the emulsion.
>
> Which film suffers from grain clumping and grain
> migration, in any
> practical processing solutions?
>
Well, without the aid of an electron microcope one can not
be sure but certainly Tri-X seems to have this problem when
developed in very alkaline developers like Rodinal. Of
course, you are right, I am assuming text book research
describes phemomonon that occur in actual practice.
>> but the company no longer has much idea of its history,
>> as I
>> found out not lonjg ago when they seemed not to know when
>> D-76 originated.
>
> What do you consider the origin of D-76, and how did you
> determine
> Kodak didn't know about it?
>
A couple of years ago Kodak released some advertising
which mentioned D-76. I don't remember the details but they
had the date wrong by several years. D-76 was first
described in a booklet describing a new Kodak duplicating
film for motion picture negatives published in 1926. One
would have to have access to internal Kodak documents to
know if there were notes made about the development of this
formula, generally attributed to John Capstaff of Kodak
Labs. Kodak disposed of all their business records and the
research laboratory's library some years ago. I was told it
went to RIT but no one there seems to know anything about
it. This came up in relation to a question I had about when
Kodak started coating lenses. No one there had any idea
whatever about this.
I think the 50 year anniversary must refer to Tri-X as a
35mm and roll film since it shows up as a sheet film and
glass plate c.1943 if not earlier
>> I wonder if the Tri-X emulsion making process drifted
>> over the
>> years and was brought back to optimum when the operation
>> was
>> moved. One would have to have Tri-X negatives of forty or
>> fifty
>> years ago developed in a common developer to tell.
>
> Based on common knowledge of emulsion making, there is no
> question
> that Tri-X changed in 50 years. Practice of emulsion
> making changed so
> much in 50 years. First of all, gelatin supply changed a
> lot, and
> photographic quality of emulsions depends strongly on the
> gelatin
> quality. There were a few key technologies and new
> knowledge in last
> 50 years that are highly valuable in economical production
> of negative
> emulsions. Then environmental regulations changed so much
> that several
> compounds used 50 years ago are not even a possibility
> today.
The comparison is with recent Tri-X made in the old
coating plant vs: the current stuff. Its possible some
change was made in the emulsion. Of course, we are also told
that T-Max film was always made in the new plant so there
has actually been no change in that film.
> Ryuji Suzuki
>
---
Richard Knoppow
Los Angeles, CA, USA
dickburk@xxxxxxxxxxxxx
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