T Max 400 Technical Discussion by Sandy King

[Michael Kadillak]

Sandy King was kind enough to provide us with a technical discussion of T Max 400 film and we wanted to provide the link to the J&C web site where this information can be obtained.

http://www.jandcphoto.com/index.asp?PageAction=Custom&ID=26

Enjoy!

[Ken Lee]

Concise, articulate, factual, no hyperbole, nothing vauge... super !

[Oren Grad]

Live link, for your E-Z clicking pleasure:

www.jandcphoto.com/index.asp?PageAction=Custom&ID=26

[Larry Gebhardt]

Do the times for Grade 2 and 3 Azo look switched to anyone else? Maybe it is too early in the morning.

[Amund BLix Aaeng]

Larry, get a good strong cup of coffee, and look again :-)

[Michael Kadillak]

Larry is correct as unintentionally the times for Azo 2 and 3 need to be modified. Sandy is making the correction and it will be corrected shortly at the J&C web site.

Thanks

[sanking]

Yes, the times were revcrsed, but they have been corrected.

There was also a wrong graph in the article that has been replaced. It was the fourth or last one one so if you downloaded the article earlier you might want to make the substitution.

Thanks for your comments, and hope the information is useful.

[Andrew O'Neill]

Hey Sandy, I use HP5+ and there is not pronounced shoulder in my curves, therefore no muddy high values when I develop it in pyrocat-HD, so your statement is not accurate. My high value curves bend slightly upward.
Tmax 400 in my experience is indeed a unique film. You can really manipulate it's curves in a big way...I just didn't like the look of it.
Really good article, on the other hand!

[Michael Mutmansky]

There is something not quite correct with your curves. The times listed in the response curves above do not match those listed in the N value curves below. I suggest you provide comparable curves to be consistant with your data.

I dispute your characterization that TMY is a better film at 'expansion and contraction' than TXT. While I agree that it is a better film for expansion in that it can obtain a higher gradient before reaching gamma infinity, I don't believe your tests can make any conclusion for contraction conditions, because it provides no information on how contraction is dealt with in a manner that makes it better than any other film available. Most films can handle contraction fairly well, because those conditions are much less demanding of the film gamma-infinity characteristics.

This is especially true in conditions of high contrast. A film like HP5 can be a very effective film in these conditions because the slight shoulder helps tame the severe highlights that can occur otherwise. This lower contrast in the highlights can result in a more satisfying image, because the shadow and midtones are at greater expansion compared to the highlights, which will result in greater microcontrast in the resultant image. Ultimately, the shoulder acts to increase the range of shadow and midtone density at the expense of highlight range. With some alt processes, this is a meaningful difference. For a reference document, refer to 'Whispered Prayers' by Stephen Harrison as an example of HP5 work that utilizes this characteristis to good effect.

The comparison charts you provide also indicate that TXT has an upswept curve characteristic shape, and the TMY has a much straighter line characteristic. These differences may be somewhat dependant on the film/develper combination, but that is another consideration in how the film renders that you have not discussed. In particular, a film with increasing gradient as the TXT has shown may be a more suitable film for conditions where a bit more contrast is desired in the highlight region. This can be of particular importance for pt/pd printers who intend to shoot and develop aiming for a low contrast mix, because the highlight region has especially low contrast. Where a straight-line curve may lose the snap of the specular highlights, an upswept curve may hold them better.

TMY is not the silver bullet of all films, but it is a good film under certain conditions, so let's not get carried away with praise for TMY as the 'one film to bind them together'. It is a worthwhile film to have in the stable, but I don't think it is the answer for all occasions. For alt process shooters, especially with the possibly limited availability of film in the future, I don't think I would be standardizing on this film exclusively, as the keeping properties (and transporting-keeping properties) of this film may cause difficulty in a few years as the B+F increases to a point where it becomes difficult to print without solarization problems becoming apparent. While in this respect, it is no better than TXT, a film like FP4+ is better in this regard, and this consideration should not be overlooked for anyone who is planning to stock a freezer full for future years of shooting.

---Michael

[sanking]

Michael,

I accept your disagreement about contraction. Most films do not have any problem with contraction so my main point here was on expansion.

Regarding HP5+, yes, any film can perform well in some lighting conditions. In fact, there are some conditions where I would prefer a film like BPF that has great latitude but virtually no expansion potential. HP5+ would also do well in contrasty light because of the tendency to shoulder (when developed to a high CI).

And yes, the incresing gradient, or flaring curve of TXT (Efke PL100 also has this) can be a great characteristic for printing with Pt./Pd. bcecause it compensates for the print shoulder in the highlights.

But how much would you want me to say in a short review of less than four pages of text? When you consider the range oif proceses folks are using and the many developers the range of possibilities for a "very best" combination is virtually infinite.

Also, I did not say tht TMY was a silver bullet. However, in my opinion a film with a very straight line curve and tremendous expansion potential is a superior film for most subject, and espeically for alternative processes, and if I could only have one film it would be TMY. But that is my opinion, and note that the title of the review indicated that there would be fact and opinion.