[pure-silver] Re: TMAX grain - developer modification?
- From: "Richard Knoppow" <dickburk@xxxxxxxxxxxxx>
- To: <pure-silver@xxxxxxxxxxxxx>
- Date: Sun, 10 Oct 2004 11:53:32 -0700
----- Original Message -----
From: "Christopher Woodhouse" <chris.woodhouse@xxxxxxxxxxxx>
To: <pure-silver@xxxxxxxxxxxxx>
Sent: Sunday, October 10, 2004 12:48 AM
Subject: [pure-silver] TMAX grain - developer modification?
> For obvious reasons, I have suddenly been plunged into
> initial film
> evaluations once more. For the same reasons, I decided to
> try Tetanal
> Ultrafin as a substitute for Perceptol.
>
> I decided to do a back to back test of Tmax 400, Tri X and
> Neopan 400. I
> expected Tmax to come up on top in terms of grain.
>
> To my surprise, it was worse than the other two. Neopan
> had the best grain,
> followed by Tri X and then Tmax. The Tmax grain was very
> clear and obvious.
>
> (For those who want to know Tetanal Ultrafin 1+19, 24C
> Jobo processor, for
> normal development (G =0.57, the EI's were 500, 320, 250
> for Tmax, TriX and
> Neopan. The evaluations were made on an 8x magnification
> from 120 film)
>
> Now to the question: I seem to remember that Tmax grain
> does not alter with
> developing agent. Is that right? Could I be seeing the
> other films
> responding to the fine grain developer and leaving Tmax
> behind? Maybe it is
> the cynic in me, but the rank order of grain is inversely
> proportional to
> the EI :)
>
> --
> Regards Chris Woodhouse ARPS
>
>
T-Max grain does vary with the developer but probably
less than other films. 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.
I have no idea what is in Ultrafin. The closest
developer to Perceptol I know if is Kodak Microdol-X. At one
time the they were virtually identical (according to the old
MSDS). Currently, Microdol-X uses lots of sodium chloride as
a fine grain agent while Perceptol contains lots of
Potassium bromide. In large quantity bromide evidently also
acts as a fine grain agent.
Both of these developers have their extra-fine-grain
property only when used full strength, when diluted they
loose it. At 1:3 they become high acutance developers. The
film speed is reduced by nearly one stop for both when used
full strength but is normal for the diluted developer.
Something has changed in Tri-X since my experience wtih
it in the past was that it was definitely grainier than
T-Max.
I will note that the trade name Tri-X has been in use
since at least the early 1940's. It may be that the current
emulsion formula is fifty years old, as celebrated by Kodak,
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.
Xtol should give a good compromise between best speed,
sharpness, and grain for all of the films mentioned. I Ryuji
Suzuki's version of Xtol should also do well. Microdol-X
will give finer grain but at the price of some speed loss
plus it doesn't have much edge/border effect when used full
strength so isn't as "sharp" as some other developers
although the resolution is not affected.
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. OTOH, they may have taken the opportunity to doctor
it to improve it.
---
Richard Knoppow
Los Angeles, CA, USA
dickburk@xxxxxxxxxxxxx
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