So what is the estimated speed of D3200?
By the way, I made a small error in my earlier calculations by including the density of a glass holder that's part of my setup twice. The estimated speed of the KODAK T-MAX P3200 is around ISO 1080. Sorry about that.
So what is the estimated speed of D3200?
According to my estimates, the ISO speed of the KODAK T-MAX P3200 is around ISO 1100 +/- 50. This speed is established by two different methods: (1) using absolute log exposure values, and (2) using relative log exposure values. I am sorry I cannot give you anything more exact than that due to the nature of my uncalibrated setup but that "ballpark" number should be sufficient as a starting point for your own testing. I made a mistake earlier in the thread by adding my glass filter density twice, so I am very sorry for the confusion.
Sorry about that! And thank you!No, that was D3200 as in Delta 3200.
What do you estimate the real rating of Delta 3200 to be?
Thank you for this thread and the measurements. It’s fascinating stuff.
That would be my working speed, too. Typical daylight (if there is such a thing) has been found to be more actinic (about 1.3 times) than sensitometer light (indandescent + 80A filter), which would account for greater speed in daylight conditions compared to film test.I just round out D3200 to a real-world working speed of 800. That seems to work superbly for me at least.
But I am interested in Tmax 3200 and Ilford Delta 3200 both @Iso 3200developed in XTOL and replenished XTOL. That is where the rubber meets the road.
All this testing and I am still no closer to the development times at 68 degrees F for Kodak Tmax 3200 and Ilford Delta 3200 both exposed at ISO 3200developed in replenished XTOL.
You almost can’t overdevelop Delta 3200. The Massiv chart times for 3200 and 1600 in XTOL stock are off. I get flat negatives when I follow them.
Give at least 20 percent more for a start.
Any chance you can illustrate this? Maybe in a new thread.
Compensating for flare is a fool's folly since that is an uncontrolled variable. Every lens and every camera configuration with or without lens hoods has different flare characteristics. Just leave flare out and let each user make their adjustments.
I finally got around to developing KODAK T-MAX P3200 and Ilford Delta 3200 in XTOL. I wanted to see how the films would respond to being pushed, i.e., to being underexposed and overdeveloped. I exposed each film for 1 EV and 2 EV less exposure than in my previous test. This would be roughly equivalent to being exposed at ISO 1600 and ISO 3200. I developed in XTOL stock (unseasond) for 16 minutes at 20C in a rotary processor (following KODAK's recommendation). The results surprised me.
First of all, XTOL, with the T-MAX P3200, produces very different curves than it does with D-76 . In fact, based on my tests so far, I would recommend ditching D-76. The XTOL curves are much better formed. That lumpiness I mentioned earlier? Gone! I was really surprised by this. XTOL produces nearly linear curves, except the long toe, of course. As far as Ilford Delta 3200, XTOL also produces slightly better formed curves, but the result is not nearly as pronounced because they were already very linear with D76. The ISO 1600 curves are in red, and the ISP 3200 are in blue.
How about film speed? So far, I have found XTOL to not produce significantly greater film speed in this test. However, this is just one test. I will repeat the test, and once my XTOL is seasoned, I will repeat it yet again.
Contrast Index (CI) is very well-controlled with XTOL, ranging from, roughly, 0.65 to 0.75. I guess this is what people mean when they say these ISO 3200 films have inherently low contrast. With XTOL, they do seem to.
So does XTOL have magic? I would say, with T-MAX P3200, there's some magic to it. Yes.
Now I am really curious how seasoned XTOL will perform.
View attachment 322757View attachment 322759
Yes, I reduced exposure with an ND filter in the light path for the ISO 1600 exposure, and then with two identical filters, for the ISO 3200 exposure. The ND filter is not perfectly grey, but close enough, I think, for such a test. The curves are plotted with the "wrong" log exposure values because each curve received a different exposure, and their relative placement along the Log Exposure axis is for comparison only. I will re-replot them once I have enough data. My program requires at least five curves to make a proper model and calculate all the required parameters.Quick question. I assume you use a step tablet to exposure the sensitometric tests. So when you write you wanted to see how the films respond to being underexposed and pushed, did you mean that you exposed the step tablet differently to achieve the underexposed test?
Yes. It's going to take a while, as I want to get the seasoning right. By the way, it looks like Ilford Delta actually did get a speed bump with XTOL, about 1/2 stop, but I will hate to wait until I have more data to see if this effect is real.So XTOL with rotary processing is better. Now we should look at replenished XTOL with Ilford Delta 3200 land T-Max P3200.
Yes. It's going to take a while, as I want to get the seasoning right. By the way, it looks like Ilford Delta actually did get a speed bump with XTOL, about 1/2 stop, but I will hate to wait until I have more data to see if this effect is real.
Yes, I reduced exposure with an ND filter in the light path for the ISO 1600 exposure, and then with two identical filters, for the ISO 3200 exposure. The ND filter is not perfectly grey, but close enough, I think, for such a test. The curves are plotted with the "wrong" log exposure values because each curve received a different exposure, and their relative placement along the Log Exposure axis is for comparison only. I will re-replot them once I have enough data. My program requires at least five curves to make a proper model and calculate all the required parameters.
Yes, thank you for pointing that out. That's what I do in my tone reproduction function, which can simulate different camera exposure, vary curves by CI and LSLR, and align (or key) curves to either highlights or shadows. Here, I was going to switch to XTOL, anyway, so I thought I'd make the exposure more realistic to how people are using the film. Most of all, I was curious how the film would respond. After all, it's got "3200" on the box. A lot of people love XTOL for its suitability for pushing film and for rotary processing. Plus, people rave about its tonality. So far, I am impressed, but it's still early days.Since the range of the step tablet exceeds the average luminance range and generally the exposure has values falling past the inertia point, you really don't have to change the exposure of the step tablet. Create a family of curves and then evaluate each by adjusting the camera image input. This way the data can be utilized in more than the one test.
Yes, thank you for pointing that out. That's what I do in my tone reproduction function, which can simulate different camera exposure, vary curves by CI and LSLR, and align (or key) curves to either highlights or shadows. Here, I was going to switch to XTOL, anyway, so I thought I'd make the exposure more realistic to how people are using the film. Most of all, I was curious how the film would respond. After all, it's got "3200" on the box. A lot of people love XTOL for its suitability for pushing film and for rotary processing. Plus, people rave about its tonality. So far, I am impressed, but it's still early days.
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