From: Richard Knoppow (dickburk@ix.netcom.com)
Date: 06/08/00-05:42:44 AM Z
At 11:29 PM 06/07/2000 -0600, you wrote:
>This is really elementary, but I wondered what everyone's BW 4x5 film
>preference is: TMAX 100 or TriX or what? If you want, you can email me off
>list if this is not applicable. I always use TMAX 100 but another
>photographer totally disagreed with that choice and I was wondering if this
>is fact or opinion.
> Another question: I have a couple film holders that are really sticky
>in the slider grooves. Has anyone ever soaked their film holders in water,
>or how better to clean that kind of residue off? Air has not done it. I
>can't figure out how to get in there to get the goop out...
>Chris
There are already enough answers on the holders.
T-Max and Tri-X or Plus-X sheet films are very different. T-Max 100 and
400 are relatively short toe films with long straight line sections to
their characteristics. Both Plus-X and Tri-X sheet films are very long tone
films with essentially no straight line portion. Plus-X is more extreme
this way than Tri-X but both are very similar.
The effect of the upward curving characteristic of Plus-X and Tri-X is
to depress the values of mid-tone grays in comparison with the straight
line film. Whether this is desirable depends on the particular image and
your taste. I much prefer the T-Max films for general use/
It should be noted that Kodak sells two quite different films under
virtually the same name. Plus-X and Tr-X in 35mm and 120 roll-film has a
completely different emulsion from the sheet film variety (both types are
available in 120 Tri-X). Plus-X and Tri-X roll film are conventional
medium-toe general purpose films. The sheet film version of both are very
long toe, in fact virtually all toe, films meant for studio use with
controlled lighting. The intention is to produce very bright highlights.
The characterstic curve of a film is pretty much determined by the
distribution of sensitivity of the silver halide particals making up the
emulsion. This is determined in the manufacturing procedure for the
emulsion. The effect of the developer is minimal in changing the
characteristic although there is some effect.
There is no one "best" film. Kodak makes these films because there is a
demand for their particular characteristics. You pretty much have to try
them on a variety of subjects to see what the actual differences are in
reproducing a given subject.
T-Max has a bad reputation with some because it is not at all tollerant
of sloppy processing. Its contrast varies faster with time and temperature
than most other films. Where most films will change contrast about the
equivalent of one paper grade by changing the time by +/- 30% T-Max will
change that much with a 20% change. The sensitivity to temperature is more
sensitive by exactly the same amount. Those who complain about excessive
contrast with T-Max are either overdeveloping it or may be missing the
slight compression of highlights that some older films produce (a
shoulder). T-Max films have very long linear characteristics and are
capable of very high densities. This is both a virtue and a vice depending
on how you use it.
Kodak has very complete data sheets on all it films on its web site, they
are available as HTML to read off the screen, and as PDF or PostScrip files
for printing. PDF requires Adobe Acrobat, which is freeware.
Kodak is at: http://www.kodak.com
IMHO, a better general purpose film than Plus-X or Tri-X _sheet_ film
is Ilford FP-4 and HP-5 Both have "normal" characteristics and are fairly
forgiving of processing errors.
Agfa film is also nice looking but I believe APX-400 has been
disontinued in some sheet sizes.
---- Richard Knoppow Los Angeles,Ca. dickburk@ix.netcom.com
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