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  1. #11

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    Pyro formulas are not known for speed.

    I'm curious, what is OPs motivation? It could help tune the responses. It seems odd for speed to be the sole criterion in developer selection - particularly since in the grand scheme of things, with the exception of speed decreasing solvent developers, the speed differences between most general purpose developers and so-called "speed enhancers" are small at best.

    I must say in my personal experience I've never observed significant speed increases, even with developers like FX2 which are reputed to give up to a full additional stop. I would say some developers maintain speed a little better with reduced contrast development, but even then, defining true speed in traditional zone system terms (0.1 over base+fog) is not necessarily the end of the story. While "0.1 over base+fog" is a useful landmark, what we are really talking about is shadow/toe contrast. Essentially by calling zone I 0.1 over base+fog we are trying to put zone I density at a point on the characteristic curve that ensures good separations are available upward from zone I. The idea is basically to put all the important shadow exposure values past the toe, onto the straight line portion of the characteristic curve.

    But some film-developer combos produce higher low value contrast than others. XTOL is an example of a general purpose solvent developer which tends to produce relatively higher contrast in the low-middle values than some other formulas. Depending on how you develop the film, you might not necessarily find XTOL gives you a higher "speed point density" than 0.1 above base+fog, but the separations immediately upward from that point will be a little stronger than with say HC-110. You might be able to rate your TMY2 at 400 in XTOL even though your true speed point might only be 0.08 above base+fog. At the same time you might rate your TMY2 at 300 in HC-110, get a speed point of 0.11 above base+fog, and still find you don't have enough contrast in the shadows.

    Then of course, as I mentioned earlier, there's the issue of contrast. With most modern films the speed (as you've defined it) will tend to move around quite a bit depending on development time, agitation etc.

  2. #12
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    Gerald Koch wrote: > fastest speed for films in general is obtained with a low pH, high sulfite, phenidone based developer

    Quote Originally Posted by Michael R 1974 View Post
    Interestingly the opposite - ie: low sulfite, relatively high pH formulas - can also give higher effective speed..
    Dear Michael, that is not true if you count speed as
    a) real density above fog
    b) you need the highlights (no blocking).

    If you use such a strong developer you lose the higlights.
    ---
    Uwe Pilz

  3. #13

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    It is incorrect to call a developer "strong" simply based on it having a higher pH alkali. A balanced, non-staining acutance developer is also a compensating formula by definition. The highlights take longer to build density due to controlled exhaustion, which allows the lowest values more time to build density. There is usually a more gradual shoulder. This is a different mechanism than the Phenidone-high sulfite speed formula. It also explains why low pH, solvent formulas with high sulfite and a relatively high concentration of Metol (eg D23, D25, Microdol, Perceptol etc) do not give compensating results unless they are diluted to 1+3 or even more, and agitation is significantly reduced. There is simply too much developing agent and preservative for controlled exhaustion to take place. Incidentally this does not mean you "lose" the highlights, just that the shoulder is less pronounced and higher up on the curve. Not necessarily a bad thing as excellent separations are available well above zone X.

  4. #14

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    Quote Originally Posted by Michael R 1974 View Post

    I'm curious, what is OPs motivation? It could help tune the responses. It seems odd for speed to be the sole criterion in developer selection - particularly since in the grand scheme of things, with the exception of speed decreasing solvent developers, the speed differences between most general purpose developers and so-called "speed enhancers" are small at best.
    I have two reasons for the question.

    1. If negatives are scanned, a program such as Noise Ninja can reduce grain, making graininess less important, and thus making true speed more important.

    2. I have a crazy idea: Develop using two developers. Bath A would be a speed-enhancing developer, and bath B would be a super fine grain developer such as DK-20. The time in each bath would be such that final density would be correct, which means that bath A would be underdeveloped (shorter time). Bath A would build up (amplify) each photon-hit, but not enough to cause grain-clumping. Bath B would do the final amplification in a manner less prone to clumping. The goal would be box-speed plus super fine grain. Or have folks already tried this?

  5. #15

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    I'm not concerned about grain when it comes to speed - I care primarily about retaining detail in shadows. I can always step up a format if grain is a major consideration.

  6. #16

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    I dont know about TMY or Tri-X but the highest shadow speed I obtained with Delta 100, sun/shade, average metering was EI=160. D-76 gave EI=80 .
    This was from Tetenal Emofin 2-Bath developer used according to the instructions (no push processing).However this was at the expense of the flattening of highlights,ie clouds not so well separated from sky.

  7. #17
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    TMY2, recently tested for me by Fred Newman at The View Camera Store with 21 steps wedge and calibrated light. Developed by me with Ilford DDX 1:4, agitation of 5 initial inversions and 5 every minute at 70 degrees (not 68 as indicated on chart). Without silly gimmicks you would get more than box speed and imperceptible grain at an average gradient of 5 to 5.5. Take this for whatever it's worth, since it is my test designed to work with my technique and fit my paper in the darkroom.
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  8. #18

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    Quote Originally Posted by albada View Post
    I have two reasons for the question.


    2. I have a crazy idea: Develop using two developers. Bath A would be a speed-enhancing developer, and bath B would be a super fine grain developer such as DK-20. The time in each bath would be such that final density would be correct, which means that bath A would be underdeveloped (shorter time). Bath A would build up (amplify) each photon-hit, but not enough to cause grain-clumping. Bath B would do the final amplification in a manner less prone to clumping. The goal would be box-speed plus super fine grain. Or have folks already tried this?
    This sort of thing has been done, although not exactly the same, and not to control grain (as far as I know). It has been used more as an alternative method for compensating development (ie extreme contractions) in an attempt to get a little more shadow contrast which can get very flat in extreme contractions. Bruce Barnbaum does this, but it is with one developer (HC-110). He uses a concentrated dilution for the first minute or so, to get the shadows going, and the the remaining development is in a very dilute HC-110. Of course, grain is not a concern since he's working with large format film. Personally I have my doubts as to whether this procedure makes a meaningful difference versus using highly dilute HC-110 for the entire development time with reduced agitation (as Ansel and others used it).

    I guess you could try. My guess is considerable experimentation would be involved. Although in the end, I still doubt this will make a meaninfgul difference in speed if you want super fine grain. A good developer for Bath A might be something like Ilford DD-X at a more concentrated working dilution than normal. However for Bath B I think the finest grain developers you could reasonably use would be Perceptol, or perhaps an Atomal-type formula, or some sort of modernized PPD/Glycin thing, or Crawley's FX-5. I don't think DK-20 is a good idea. It is almost certain to produce dichroic fog with modern films. It's a long outdated formula.

    One other note - regarding "grain clumping" - ie migration. With modern, hardened films, my understanding is this basically does not happen, or that at least the jury is out. We've had some lenghty threads on this in the past.

    Incidentally, my testing results with DD-X are consistent with what Max posted above. Of all the general purpose solvent, mild-pH MQ or PQ developers I've tried DD-X produces the highest speed, essentially box speed with many films.
    Last edited by Michael R 1974; 11-01-2011 at 10:34 AM. Click to view previous post history.

  9. #19
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    ..and as a comparison, TX 120 with XTOL 1:1, 70 degrees, 5 inversions initial, and 5 ever 30 seconds. Not quite DDX but close.
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  10. #20

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    ...also consistent with my findings, although even though the speed point is slightly lower with XTOL, I find XTOL favours low and mid value contrast a little more than DD-X, which is something I like. It is also slightly finer grained than DD-X. The differences are small though.

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