The effect of underdevelopment

Hi Forum, until very recently I was under the false impression that Kodak Tri-X 400 and Tmax 400 were the same thing. When I checked I discovered that when using Kodak D76 at 20C, TriX requires 9:45 of development whereas Tmax needs 10:45. This means that I've been developing all my Tmax films too briefly although I've never really experienced bad results. Recently however I purchased some very cheap film (ISO 400) which is meant to be developed as one would develop Tmax. The negative of this film turned out very pale looking, that is, the shots appeared underexposed. A roll of Tmax that I developed together with the cheap film in the same tank turned out OK. Perhaps Tmax gives more latitude. Are pale negatives consistent with underdevelopment?

Thanks,

One minute more or less at a roughly 10 minute developer time is only 10%. That's why both your Tri-X and TMax 400 negatives print well (I assume you are printing, since this is not the hybrid, soup and scan forum-LOL).

Many ISO 400 films are no such thing. The only way you can check the true speed is to shoot a test.

The best thing to do when introducing a new film into your workflow is to test the film side by side on both one of your known good films and the new film, do an exposure series on each and process together (most 400 films process for about the same time, and yes I know there are a lot of exceptions, Kentmere 400 comes to mind for one example). Process together and then print all the prints in the exposure series on both your known good film and your unknown.

In my experience TMax 400 has a great deal of both exposure and processing latitude and Kodak for many years recommended no additional processing time for negatives shot at ISO 800, twice the official ISO rating. A good TMax negative will look thin compared to a good negative shot on a more conventional film, e.g. Tri-X.

My own personal settings? I shoot Tri-X unpushed at EI 250 and TMax unpushed at EI 400. And use D-76 1+1 (or Acufine if I need to push). Again these are personal setting and I tested to get there.

Kodak Tri-X 400 is a traditional grain film and Kodak Tmax 400 is a tabular grain film. The only relationship is that they are manufactured by Kodak.

Sirius Glass said:

Kodak Tri-X 400 is a traditional grain film and Kodak Tmax 400 is a tabular grain film. The only relationship is that they are manufactured by Kodak.

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Thanks. I'd read somewhere online that the name had changed to Tmax - and I believed it....

darkroommike said:

The best thing to do when introducing a new film into your workflow is to test the film side by side on both one of your known good films and the new film, do an exposure series on each and process together (most 400 films process for about the same time, and yes I know there are a lot of exceptions, Kentmere 400 comes to mind for one example).

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Yes, good idea. I'm lucky to have an Nikon F5 on loan which can bracket one stop over and below the correct exposure. I was thinking of setting the ISO on the camera to 200 and bracketing this way. What do think? Or should i try a much wider range?

Oh and by the way I am a scanning person for lack of an enlarger, should I have really posted to a different forum for a strict film question?

All the best!

Xícara said:

The negative of this film turned out very pale looking, that is, the shots appeared underexposed. A roll of Tmax that I developed together with the cheap film in the same tank turned out OK. Perhaps Tmax gives more latitude. Are pale negatives consistent with underdevelopment?

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It would help us to know exactly how this other film was labeled.
Overall, though, it's not uncommon to give more exposure than a strict reading of the meter at box speed would indicate and then to give a little less development than normal - which is possibly why your TMax negs look ok.

winger said:

It would help us to know exactly how this other film was labeled.
Overall, though, it's not uncommon to give more exposure than a strict reading of the meter at box speed would indicate and then to give a little less development than normal - which is possibly why your TMax negs look ok.

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Thanks. Marked as follows:

Nation Photo. B&W Film. ISO 400/27º . 135 . 36 Exp

Xícara said:

Recently however I purchased some very cheap film (ISO 400) which is meant to be developed as one would develop Tmax. The negative of this film turned out very pale looking, that is, the shots appeared underexposed.

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When you say that the Nation Photo film is "meant to be developed as one would develop T-Max" which developer are you referring to?
I ask because it is not uncommon for two films to require the same development time in one developer, but two different times in another developer.
The choice of developer really does matter.

MattKing said:

When you say that the Nation Photo film is "meant to be developed as one would develop T-Max" which developer are you referring to?
I ask because it is not uncommon for two films to require the same development time in one developer, but two different times in another developer.
The choice of developer really does matter.

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Thanks. They don't actually specify. Here are the instructions (at bottom of page): https://shop.nationphoto.com/negatif-noir-et-blanc/7441-nation-photo-400-135-36.html

But in any case, I use Kodak D-76 1+1 at 20ºC which should be a good match.

Cheers,