Reducing the Dmax of Tmax 100

[Ed Richards]

I am trying to adapt the zone system to scanning and digital printing of 4x5 B&W negatives. I am using Tmax 100 and Tmax RS. In the mid and low tones, i.e., moderate and low density areas of the negative, it scans beautifully on a consumer scanner (Canon 9950). The highest density areas are the hardest to scan, of course, and I have been working on reducing the Dmax a bit. At least for scanning, I am finding Tmax to be very robust and not dramatically sensitive to variations in development, as long as the base exposure is adequate. I do not like to use developing times of less than 6 minutes at 75 degrees, but even at 1:15 I still get pretty dense highlights on high brightness range scenes. Any tips for reducing the ultimate Dmax a bit with Tmax RS?

[Mark Sampson]

Dilute the developer further, or process at 68F. Those changes will keep your times long enough while reducing contrast.

[Ed Richards]

More dilution makes sense - anyone have experience with Tmax RS beyond 1:15? Lower temps are hard here in the topics of Southern Louisiana.:-)

[Paul Fitzgerald]

Hi Ed,

"I am finding Tmax to be very robust and not dramatically sensitive to variations in development, "

Usually TMX is as touchy for temp. as E-6. Try D-76, fresh mixed-one shot-stock@70*F for 7 min., it should put you in the ballpark. When you find it, try to keep the temp +/-.25*, it is that touchy. TMY is more forgiving.

Just a thought.

[Paul Butzi]

I use TMX in 4x5, scan it on a Microtek Artixscan 1800f.

For years I used Tmax-RS diluted 1+9, developed at 75f.

I did some tests, though, and found that I got much better results scanning TMX negatives developed in XTOL 1+3 than I did in Tmax-RS.

You might like to try XTOL and see if you get better results.

-Paul

[Ed Richards]

Paul - better results in that the dmax was reduced to better stay within the scanner range?

Dan - I am definitely over exposing. My objective is to see if scanners benefit from an entirely different approach to negatives. Local contrast is much easier to deal with in the digital domain than when printing on paper because digital lets you fit the dmax of the negative to print media. Since the print media (silver or ink) has a very limited dymanic range, there is a lot of extra brightness info in a scan in the mid ranges over what you need to print, so you should be able to use a more compressed negative all the time. Thus it may be possible in the digital world to use N-x development for almost everything, with the only objective being keeping everything within the range of the scanner and not letting the grain get too big. Thus with some over exposure and scanning, Tmax suddenly becomes much less touchy. (Or maybe I am dead wrong - I will keep you posted as I work through the testing.)

[Paul Butzi]

No, better results in that the noise/grain of the scanned image was lower, and the resolved detail was better as well.

I'm perplexed by your experience that TMX is unresponsive to development controls, since I find that to be the opposite of my experience.

I think you will find that your ideal of providing overly generous exposure will not give you optimal negatives. In my limited testing, increasing negative density produces an increase in noise, both grain size and scanner noise.

As a result I've changed my exposure practice to try to keep shadow density as low as possible without having important detail get crushed by the abrupt toe of TMX, and I have reduced development generally to keep high density lower (and thus reduce noise).

I don't find that I need to make much of an adjustment in film speed to handle the changes in development.

[Jay DeFehr]

I have no experience with scanning film for digital printing, but the discussion here suggests that developer choice might be very influential. It seems that a soft working, fine grain developer is indicated. I would consider a metol-only, two bath developer like Stoeckler's:

A

metol 5g

sodium sulfite 80g

sodium bisulfite 20g

Water to 1 liter

B

borax 10g

water to 1 liter

For TMX try: 3min A/3min B

Do not pre-soak your film. Contrast is controlled by time in bath A, and time in B is constant. Agitate continuously in bath A, and very gently for 10 sec./minute in bath B.

This is a very economical developer (the A bath is not exhausted by development, as no development takes place there, and will remain useful for as long as solution volume remains adequate) and should deliver the negative characteristics you're looking for. Good luck.

Jay

[Ed Richards]

> I think you will find that your ideal of providing overly generous exposure will not give you optimal negatives. In my limited testing, increasing negative density produces an increase in noise, both grain size and scanner noise.

I was not very clear. I am trying to get the lowest negative density with all the info. When I said over exposure, it was relative to the shortened development times, not in absolute terms. In zone terms, I am placing my lowest shadow detail at Zone 3, rather than Zone 2. I am not there yet, I am still over exposed relative to the develoment, which is why the Tmax is not so sensitive.

> I don't find that I need to make much of an adjustment in film speed to handle the changes in development.

That is what I mean by saying that Tmax is relatively robust. I expected changes in development to require much more aggressive changes in exposure.

Jay - I was a chemist in a previous life and I am not going back to it in the bathroom.:-) I am using Tmax Rs because it is a clean one shot developer as part of an all liquid, one shot system.

Paul - do you have info on how you use Xtol on your WWW site?

[Henry Ambrose]

Ed,
One thing for sure is that Xtol at 1:3 will require fairly long times compared to your current developer - which is a good thing for your situation and TMax 100 is excellent in Xtol. What you are trying might be a good way to go for scanning and it sounds like to me less development is all you need.

As to Xtol at 1:3, keep in mind that you will need at least 100ml of stock per 80 square inches of film. Mix with distilled water and keep it in glass with no air. Its about that simple. If you don't have the old Kodak .pdf with 1:3 times I can send it to you.

Xtol 1:3 is pretty hard to beat with most films. The downside some see is that it does make for longer development times but I think of that as a benefit in that its easier for me to get great film every time and I don't care if I take an extra few minutes to get it.

I would think that your TMax RS could be fine diluted further. I'd guess 1:30 at half again the time would be a place to start. Again keep the minimum amount of stock in mind. However I have no experience with this developer and could be all wrong. One sheet of film and a little TMaxRS is all you have to lose if you try it.

[Paul Butzi]

Ed-

No, I don't have XTOL times/temps on my web site.

I guess I'm still surprised that you're getting really dense highlights that are hard to scan. My N-1 time for TMX at 75f, Tmax RS diluted 1+9 is 6.25 minutes.

I would expect that diluted 1+15, you'd be looking at N-2 at least.

Remember that the battle against noise when scanning takes place on two fronts - if the negative contrast is too high, then you get more noise as you can the highlights, both because of increased grain and because of scanner noise.

If the negative contrast is too low, you get noise because the gain in the scanner amp must be turned up and because the constant noise floor becomes substantial relative to the signal, which leads to overall noisy scans.

[Ed Richards]

> I guess I'm still surprised that you're getting really dense highlights that are hard to scan.

It is not that they are too dense to scan, but that I am trying to find out how much thinner I can get them and still get the same info out.

> If the negative contrast is too low, you get noise because the gain in the scanner amp must be turned up

I think the scanner gain is held constant, but what you see is the signal dropping into the noise floor as the software attempts to maintain the black and white points. To get a better idea of what is going on, I use Vuescan and write the raw, unscaled and uncorrected CCD data from the scanner to a TIFF, then apply the gamma, resize, and convert to a positive in my image editor. Looking at the raw scanner data, both visually and with the levels controls in the editor, gives a very direct look at the real dynamic range the scanner is capturing. My objective is to maximize this raw data, because that will lead to the most data for the image. This means keeping the density away from the extremes at either end of the range. (Most of which would not be necessary if I had a drum scanner, but I am trying to make the most of the scanners that most of us can afford.)

[Conrad Hoffman]

IMO, there's a big flaw in the logic here. The assumption is that when you reduce development, the curve simply changes slope. My experience with TMX (not LF, I admit) and dilute Xtol is that reduced development causes the film to suddenly shoulder off prematurely. At first, it looks like the highlights are under control, but the reality is that the dynamic range becomes very limited. Exposure has to be dead on, and if the scene has much range, the highlights get compressed. Obviously some degree of N- development is possible, but not so much as one might think.

[Paul Fitzgerald]

Hi there,

Ed,

Your question and answers reminded me of something, so I looked it up and found it. You could try Flexicolor C-41 developer, it was suggested in Kodak's Tech Pan data sheet #P-255 and an article by Hans Dietrich for lowering Tech Pan contrast. Apparently worked very well. Tech Pan time was 10 min@68*F. It may be worth a try, great keeping properties, ultra-fine grain, long straight line with no shoulder, low base-fog, any temp. you could use.

Good luck with it.

[Ed Richards]

Thanks for all the tips! From all the info, I think must be overexposing more than I realized and that I need to reshoot my test negs with a series that has less exposure. I thought I had bracketed the range, but I may not have, which would explain why there is so little difference with different processing.

[Henry Ambrose]

Conrad,
You don't need much minus development to keep the highlights within the range of a flatbed scanner. Not even N-1 would be required, just back off a little on development until you get what you need in the dense parts of the negative.

Ed,
What you'd want in an ideal situation is for the minimum and maximum densities of the film to just fill the range of the scanner. If your film's range is too compressed so that you are "pulling the histogram apart" in your scanning or editing software you'll have more problems. The idea is to fit the negative to the scanner's ability. Just as if it was paper. I think this is what you are about, is it not?

Good luck on your re-shoot!

[Ed Richards]

> I think this is what you are about, is it not?

Right. I am just more conservative about the range of the scanner, which is consistent with the low dmax recorded in the new scanner test posted to the site.