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  1. #1

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    T-Max 400 has boomerang curve

    As part of testing a new developer I've created (in "Progress on XTOL-concentrate" thread), I've been testing and plotting all films made by the big three makers. T-Max 400 has this interesting curve:

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    It's shaped like a boomerang, and that will cause highlights to block up sooner. If you're spending much time burning-in your highlights with T-Max 400, this might be why. For comparison, here are curves for HP5+:

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    Once past the toe, HP5+ marches in a straight line like a soldier. This also shows that my own test equipment and methods aren't producing that boomerang curve. I saw this issue with T-Max 400 a few months ago, but I blamed my own testing. But results with other films show that my tests are okay. Interestingly, Tri-X also makes a boomerang:

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    But the boomerang for Tri-X is facing up instead of down, and the change in angle is small. It'll give you a bit of compression (compensation) in the highlights.

    T-Max 400 worries me. In a prior posting, PE said this means that Kodak is having trouble blending emulsions correctly. I think T-Max 400 has two emulsions. Hold a piece of paper against the monitor to use as a straightedge, and you'll see that the curve consists of two straight lines. I suspect their slopes are supposed to be the same.

    Mark Overton
    Attached Thumbnails Attached Thumbnails TriX-14.11-209D-XTOL.jpg  

  2. #2
    jp498's Avatar
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    My highlights are awesome with tmax 400; never have to burn them in. I use pyrocat HD or PMK and develop in patterson tanks or combiplan tanks. What you haven't mentioned is your agitation scheme? Rotary processing? Tank? Developer and dilution? Lots of things can change results to be different than what you've posted. It's a versatile film, and "responsive to changes in development".

  3. #3
    Rudeofus's Avatar
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    Is there a chance that these TMAX 400 curves straighten out somewhat if you dilute your developer?
    Trying to be the best of whatever I am, even if what I am is no good.

  4. #4
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    I'm surprised by those curves. They look nothing like the data I have seen. Something is wrong with the film or the process (agitation?) or whatever.

    I would check it out with other options and then contact EK if this persists.

    PE

  5. #5

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    I'll run some TMY-2 tomorrow and see what curves I get.

  6. #6

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    Further info about my process:

    I agitate using Fuji's method: Once per minute.
    I'm using a stainless steel single-reel tank with 200-210 ml of developer (barely covers the film).
    XTOL was used stock (not diluted).
    The T-Max 400 is batch number 0167 bought a few weeks ago and kept frozen, and the XTOL was mixed last week. So everything is fresh.

    Regarding more dilution: The concentrates shown in those curves are similar to XTOL diluted 1+1, so I doubt dilution makes a difference.

    Regarding agitation: The concentrates take about twice as long to develop, so they'll get twice as many agitations as XTOL. Since they develop at half the rate of XTOL, the behavior of the concentrates should be similar to agitating XTOL twice per minute. Yet the curves are identical. I'm curious to see what curves Michael R gets...

    Mark Overton

  7. #7
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    I would contact EK. This looks like too little fast component or a keeping problem.

    PE

  8. #8

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    A few more notes:

    In both graphs for T-Max 400, I waited 23 hours between exposure and development. Films have different latent image keeping (LIK) characteristics, and the delay was to simulate real-life usage. I suppose it's conceivable that the two or more emulsions in T-Max 400 could have different LIK decay-rates, so the curve could change based on exposure-to-development delay.

    This boomerang is a form of upsweep. In the thread on "Kodak Tri-X- D76 vs HC110 Dilution B (upswept curve look?)", Bill Burk says he believes that upsweep helps portraiture by improving tone-separation in faces. I didn't think of that. I was thinking more of what upsweep would do to sky and clouds.

    jp498 said "My highlights are awesome". There are a number of possibilities, one of which is that I goofed. Or you might be using a different batch of TMY2. Or maybe TMY2 with pyrocat or PMK produces a straighter curve. Do you have a Stouffer step-wedge? It would be interesting to get the curve.

    Anyway, I exposed a new roll last night, and I'll let it age (LIK) and decide what to do with it once Michael R's results are in.
    Michael: If you post or PM your densities to me, I can plot them using my gnuplot script.

    Mark Overton

  9. #9
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    My curves using X-tol 1+1 are similar. I just have a hump which goes up in the lower half. I would say I also have two curves in one but the upswept part is relatively high up so if one doesn't over expose too much it should still be fine.
    Checking my other developers they nearly all have this hump. Different but somewhere to be found.

  10. #10

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    I think I remember reading that the upswept curve was favored by studio photographers. But they have control of lighting that we landscape photographers don't have.

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