i have briefly looked under the'film' section and i couldn't find it discussed b4, but i'm sure its embedded within other threads..so my question is based primarily on kodak tri-ex 400. yep, the traditional b&w film. 1). i'd be interested in the EI ratings set and for what reasons. 2). sometimes i uprate to 800, other times 1600 and push +1, +2 accordingly. i'm looking for a contrasty image without losing too much midtone and shadow detail. so punchiness with good tonal range is what i'm after, one of my labs tell me to just shoot normal (rate it at 400, or slightly below, as its supposed real rating is closer to 320) and they will process normal and then achieve the look i want at printing stage. 3). so, just wanted to know what combinations people use and for what effect. 4). i have read several times, people rating 400 asa film at 200 EI, am i presuming they are pulling on the processing? but would this give you a flat/muddy image? now why would someone want this result.. 5). can i achieve the contrasty/punchy effect by just using say an orange filter and rating & processing normally. ie. get the best of both sides of the equation: [orange filter = increased contrast] + [normal rating & processing = keep tonal curve intact] 6). any other films which you might recommend. i have seen some spectacular shots on FP4, it seems to produce incredible tonal range..

thanks folks,

-- sparkie (sparkie@mailcity.com), November 16, 2001

Answers

Tri-X @ EI 200 in D76 1:1 with benzotriazole.

-- Cosmo Genovese (cosmo@rome.com), November 16, 2001.

Tri-X @ EI 200 in D76 1:1 with benzotriazole processed Normal.

-- Cosmo Genovese (cosmo@rome.com), November 16, 2001.

For some time I've been shooting Tri-x at 800 and developing in ID-11 or D-76 (1:1, 12 mins, 20 deg C). I'm feeling it's a bit too harsh, contrasty, on average. I usually have a wide variety of lighting situations on a roll and while pushing a stop is great for some shots, it definitely is too much for others. I'm going to try to dial it down a bit.

-- Jim Shields (jim.shields@tasis.ch), November 16, 2001.

Based on my tests, I rate Tri-X Pan (ISO 400) at EI 200 and soup it in D-76 1+1 at 68F for 9 minutes. I use a condenser enlarger. However, there's enough differences not only in our individual processing habits but also in the local water ph, meters, and shutters that only your own individual testing will tell you at what EI to rate Tri-X. If you haven't done a film test before, check out Tom Halfhill's two part article. You can find part 1 at www.halfhill.com/speed1.htm l.

In brief, I rate a particular film at a specific EI so that when I place an element at Zone III I will get good shadow detail when I develop normally and print the negative using a grade 2 filter. I usually don't deviate from normal development when I'm using roll film. I deal with contrast as best I can during printing. YMMV.

If you want to learn more about why you should rate a particular film at a particular EI I highly recommend reading a book on the Zone System. I've found Ansel Adam's The Negative readable and comprehensive. If you prefer a URL, www.cicada.com/pub/photo/zs / offers a clear and approachable description of the Zone System.

-- Bong Munoz (bong@techie.com), November 16, 2001.

Sparkie,

I am of the opinion that you can not push film speed. You can under expose and over develope but the sensitivity of the film to light never changes. Period.

Every film has a sensitvity curve (H&D curve) that for a given exposure with a given developer you will get some density on the film. I prefer to keep within the straight line portion of the curve avoiding the "toe" or "shoulder" of the curve. This gives you the maximum range of densities on the negative that have a straight liniar relationship. The more exposure you give the film the denser it gets and the whiter it prints.

To determine the speed or sensitiviy of a film, you expose for a near black (Zone 1) and bracket two stops under, normal, and two stops over. In the case of Tri-X that would be 100, 200, 400, 800, 1600. Develop the film per the reccomended time & temp.

Then when you make proof of the negative, make a proper proof. A proper proof is a proof where you expose the proof for the minimum time that produces a maximum black through the clear unexposed portion of the film (just shoot a blank frame or two). Once you know the proper proof time you can find the frame that is just a shade lighter than the maximum black (Zone 1). That frame tells you your film speed for:

1. The film used.

2. The exposure meter used.

3. The developer used.

4. The paper printed on.

5. The paper developer used.

This will establish the dark to mid tone ranges (zones). It does not place the upper zones correctly. Developing time controls Zones 7, 8, 9, and 10.

You now have to determine how long to develop to get a Zone 8 to come out correctly. Expose 3 rolls and place an epouseure on zone 1 and another on zone 8. Develope one roll for the reccomend time, one for 30 secs more, the last one for 30 secs more.

Make proper proofs. Find the frame that placed Zone 8 and zone 1 correctly. If nonw did, find the one that is the closest. Expose 3 more rolls and develope 30 sec more or less as required.

You will now have figured out the correct EI for Tri-x and developing time for:

1. The meter used.

2. The developer (and thermometer used).

3. The papaer & print developer used.

Years ago I simplified my life and I only use one film, developer, paper, and paper developer. For me that is HP5+, Hc110-B, Ilford Multigrade FB, and Dektol. My EI is 200; 35mm film developes in 5.5 minutes; 120 film takes 6. These times are correct ONLY for me, my meter, my thermometer, ect.

-- Tony Oresteen (aoresteen@mindspring.com), November 16, 2001.

Sparkie,

Tony pretty much sums it up when he says you can't really change the film speed by changing the development. But there are some developers that may increase the shadow speed slightly (say, 1/3 stop or less). One such is T-Max developer, whcih Kodak literature says is a "push" developer. You might also get a shadow speed increase with XTOL, compared to D-76. But we're talking about a shadow speed increase to maybe ISO 500, not 800 or 1600. Neverless, Kodak publishes developing times for one- and two-stop "pushes". Naturally, there must necessarily be a loss of shadow speed (and contrast increase) in doing so. Also, T-Max film is held by some (e.g. Kodak)to be more pushable than other films.

The bottom line, though, has to be that no developer can put an image on the film if one ain't there to start with!

-- Bob Fleischman (RFXMAIL@prodigy.net), November 19, 2001.