T Max 400 Technical Discussion by Sandy King

[Ken Lee]

Thanks Oren -



Where might we find some data on the various Silver papers, their curves, etc ? The few articles that I have read, deal with films, and their suitability to the Pt/Pd process.



I imagine it gets fairly complex, when dealing with multigrade papers, but it strikes me as being more important than the study of film, since it's the final link in the chain, where the rubber meets the road (if you'll pardon the mixed metaphor and cliches).



I recently compared some Selectol-soft to Dektol. At first, I thought that the "softening" effect was merely equivalent to a change from a #2 to a #1 filter - until I made an image with the same paper, using Dektol, and a #1 filter. It is not the same: the distribution of tones is different, not just elongated. The Selectol curve, for that paper if I were to discover it, was a curve, not a straight line, and the aesthetic effect was quite different.



If others have already made some investigation, I for one, would love not having to repeat it !

[robert_4927]

Sandy, Thanks for your efforts in the research and testing of various films and developers. You have narrowed the learning curve in many instances for many of us. But like Kerik said " no good dead goes unpunished". So please don't allow that to be a deterrent to your efforts. Keep up the good work.

[Oren Grad]

Ken -

Although many paper manufacturers publish characteristic curves, I don't know of any published or posted data systematically showing the effect of paper developers on curve shape. I think there's hardly any, actually - certainly far less than the already limited information on films. So if you want to study this variable and control it precisely, you're probably best off getting your own step tablet and densitometer. The upside is that it's even less hassle to do the paper tests than it is to do the film tests.

As for the rest, no "punishment" of Sandy intended. He's a big boy and can defend his own point of view admirably in a debate, as demonstrated once again here. I think that between the various comments and his responses, the TMY "story" is clearer. I appreciate Sandy's taking the trouble to respond substantively, and I'm happy with the exchange.

[sanking]

Ken,

The only accumulated data of this kind I could point you to would be the paper curve files on Phil Davis' Winplotter program. There are lots and lots of papers covered in the data, but a fairly limited number of developers. However, given the many variables of light sources and VC filters, and how these interact with the exact spectral sensitivity of VC papers, any information you find published will likely deviate to some extent from your own conditions, so Oren's advice to do your own paper curve testings is sound.

There is is an interesting article somewhere on the AZO forum that compares different developers, and dilutions, on the curve of AZO papers. This includes Dektol, Neutol, Amidol and Ansco 130. If you can find the article you will see that there are some very significant differences in the way these various developers change the curve. I would include the page but in a brief search a few minutes ago I was not able to navigate to the article. Perhaps that section of the AZO forum has been eliminated or is temporarily unavailable?

[Sal Santamaura]

"Perhaps that section of the AZO forum has been eliminated or is temporarily unavailable?"

It's on the site, but not in the forum. See DJ's article here.

As an aside, there are many flavors of Neutol. The one typically used with Azo is Neutol WA.

[Oren Grad]

How about these?

unblinkingeye.com/Articles/Azo/azo.html

unblinkingeye.com/Articles/Azo/azo1.html

[Rick Moore]

Sandy,

I thought I was the only one who remembered Royal Pan. It was ASA 400, and was similar to TMY in its ability to produce negatives with high density ranges suitable for salted paper, albumen and POP printing. It produced very clean, low fog negatives in HC-110. My last frozen stocks of it ran out in the late 90's and I still miss it.

For my uses, negatives with a DR of 2.2 or higher are necessary. TMY is without equal in this ability today. BPF and TXP are fine films, but simply cannot produce the needed range. I realize that silver gelatin printers probably wont' appreciate this capability, but it's absolutely necessary for my work.

TMY's excellent reciprocity failure characteristics are an added bonus.

[Ken Lee]

Thanks so much for the info and the references. I am encouraged to test the next formula on my list: Formula 130. I'm not ready to do any rigorous tests yet, but it's encouraging to know that it is among the most linear of the formulas.

You guys really are top-shelf. Many thanks !

[Jimmy Peguet]

Michael wrote above "...and inherent to the reciprocity characteristic is the greater propensity for the film to fog with time, heat, and rediation." I wonder about the relationship between reciprocity and film storage : Michael, if you are still here, please could you tell more ?

I asked the same question on the french forum galerie-photo www.galerie-photo.info/forum/read.php?f=1&i=590&t=466 and got some answers with a list of books. If you read french, are we talking about the same thing ?

Jimmy