From: Richard Knoppow (dickburk@ix.netcom.com)
Date: 07/18/02-03:10:19 PM Z
At 09:04 AM 07/18/2002 -0700, you wrote:
>Thanks for all the info about T Max. What developer do you use with it? Is
>there any advantage to using T Max developer instead of say D-76?
>
>> I am not sure exactly what makes T-Max film more finicky, perhaps just
>> the thin emulsion.
>> An examination of the time vs: contrast curves and time-temperature
>> tables shows that while about a 33% change in development time results in a
>> one paper grade change in contrast for most film only a 20% change is
>> needed for T-Max. Since development is temperature dependant its also more
>> sensitive to the developer temperature.
>> T-Max is also capable of very high densities. It doesn't seem to shoulder
>> off so its possible to get negatives which are hard to print....
>>
>> ----
>> Richard Knoppow
>> Los Angeles, CA, USA
>> dickburk@ix.netcom.com
>
There are two T-Max developers (thanks, Kodak). T-Max and T-Max RS. They
are slightly different although both appear to be Phenidone-Hydroquinone
developers. T-Max RS is a replenishable developer (the developer stock is
its own replenisher). It can be used for any kind of film. T-Max is use for
multiple rolls by increasing development time or used one shot. It can't be
replenished. Kodak recommends against using T-Max for sheet film because it
produces dichroic fog. I suspect this happens only when its re-used or used
up to near its capacity. It seems to be slightly finer grained than T-Max RS.
Both developers tend to produce long straight line characteristics, low
fog, and are capable of very high Dmax. They are medium grainy.
T-Max is also a good push procesing developer and delivers near maximum
film speed.
D-76 is finer grained. It delivers full film speed with normal
development but will not push as far as T-Max or achieve quite so high
Dmax. It also tends to shoulder off at very high Dmax, not significant for
normal negatives but it may not be ideal for the bulletproof negatives
alternative printers sometimes want.
Both developers are reliable and long lived.
Working solutions of both T-Max and D-76 can be diluted 1:1 to lengthen
development time. Some modern films develop very quickly. Lengthenigh the
time results in more uniform development and better control. There seems to
be no effect on grain or speed for either of these when diluted. At 1:3
D-76 begins to show considerable acutance effects (edge effects). Kodak
does not give times for D-76 diluted 1:3 but Ilford does for the nearly
identical ID-11.
Xtol gives finer grain then either of the above and is a good push
processing developer. Xtol also tends to give long straight line
characteristics. Its main drawback is the reported unreliability. I think
this is due to local water quality but have no substantiating proof.
Phenidone based developers, like Xtol, T-Max, Ilford Ilfosol-S, Ilford
Microphen, tend to yield slightly increased film speed, about 3/4 stop for
most film, for the same CI, when compared to D-76. Developers with bromide
in them (say Rodinal) or with high solvent action (D-25, Microdol-X,
Perceptol, all when used undiluted) tend to yield lower film speeds than D-76.
The effect on the film curve is not great but noticable. T-Max and Xtol
giving higher mid gray densities in the negative than D-76.
After testing several developers I settled on D-76 1:1 for T-Max film
(and most others). I do mostly conventional printing, not alt printing, so
my requirements are somewhat different.
---- Richard Knoppow Los Angeles, CA, USA dickburk@ix.netcom.com
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