Tri-x 400 at 25,600

Discussion in 'B&W: Film, Paper, Chemistry' started by Joe O'Brien, Jul 3, 2011.

  1. Joe O'Brien

    Joe O'Brien Member

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    I've got some tri-x to play with, and I've got Adox APH 09, I'm hoping to use this as a rodinal equivalent and push this film through semi-stand development. The MasDev chart says 51 minutes with 30 seconds agitation and then agitation every five minutes. That is for rodinal 1+50, anyone have an idea where I should start?
     
  2. 2F/2F

    2F/2F Member

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    Hi,

    Uprating a film doesn't mean you are changing it's sensitivity to light (film speed). It just means you are lying to your light meter and saying that you have a faster film, when you really do not. Thus, when you uprate, all you are doing is underexposing the film by using an EI that does not match the ISO film speed.

    So, Tri-X at 25,000 is SIX stops underexposed (25K, 12.5K, 6.4K, 3.2K, 1.6K, 800, 400). Think about what that means in terms of tonality. Everything shifts down 6 notches on a gray scale. This means that anything not distinctly brighter than middle toned in the composition (above Zone VI) will be rendered without any detail, texture, or even any tone. I.e. everything will be pitch black except for things that were quite bright at the scene of exposure. And there is absolutely nothing you can do in printing to put texture or detail back there. It also means that the brightest whites in the composition will be exposed as middle gray at best. Therefore, anything between middle gray and the brightest whites will be dark shades of gray.

    Pushing your film can only do so much. It is limited by what is placed there with exposure in the first place. Pushing most affects the areas that have received the most exposure, and vice versa. If middle gray is the highest anything was placed with exposure, that can only be raised so much by pushing. And Zones 0 - IV, where most of the printable area of your picture will end up falling, cannot be pushed all that much.

    BTW, ISO 25,600 is a digital-only number. ISO never specified details for speeds over 10,000, I believe, but something they published at one point suggested that if they had, they would have gone to 12,500 as the next number, not 12,800. So, I think EI 25,000 is the best way to refer to it when speaking of film.

    At any rate, stand development is exactly what you don't want in this situation. You want aggressive agitation in a strong, speed-supporting developer. Diafine is great at supporting the low tones, but won't do much to punch up the high end. I might use Microphen. Or, I might use Diafine followed by Microphen and see what happens!
     
  3. polyglot

    polyglot Member

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    Respectfully 2F, no. Pushing does actually give a speed increase and (semi-)stand development can give a significant true speed increase. And the contrast increase from pushing does mean that highlights will still print as highlights; it's not like you're just shoving the tonal scale down into darkness, it gets stretched.

    If you (semi-)stand develop in a compensating developer like Rodinal, you can actually get a significant increase in sensitivity of your film without an unmanageable increase in contrast because development continues in the shadows while development pauses in the highlights. Asking for 25,600 is too much though, even for 400TX; with that optimistic of a push, you really will end up with only highlights at most.

    If you've got film to play with, try it at 1600 and 3200 first. Those sorts of speeds are achievable with care whereas 25,600 is just too optimistic for this film, especially if you've not done some experimenting first.

    As a constructive suggestion, I would go for Rodinal 1+100 (at least 600mL to ensure that there is at least 6mL of concentrate per roll; 300mL if it's just half a roll) for one hour. 30s of agitation at the start then three or four inversions once every five or ten minutes. Do a test with just a few frames and use the following corrective procedure:
    - not enough contrast / highlight density => more frequent agitation
    - too much contrast => less frequent agitation
    - not enough shadow detail => longer time
    - thick negative => less time
    - vertical streaks (bromide drag) => shorter gaps between agitation

    In theory at least you can do agitation for 30s then once again at 1 minute and leave the thing to just sit there for two hours. If you're lucky, you will get an excellent result but you run the risk of bromide drag ruining the negatives; it's evident as dense streaks down the negative starting at the highlights. If you're not getting bromide drag no matter how long you wait between agitations, you can take that full stand-development approach. If you are getting bromide drag then your only choice is to have more-frequent agitations, which means more contrast. The increase in contrast will often be the limiting factor to the speed you can achieve.

    One drawback to (semi-)stand is that the compensation effect can make the highlights a lot less sparkly than with normal development.
     
  4. Matthew Rusbarsky

    Matthew Rusbarsky Member

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    Here's TriX at ISO 12K. Rodinal 1:100, semi stand for 2 hours. After initial inversion, give it a few swirls and maybe an inversion every 30 min.

    [​IMG]
     
  5. dr5chrome

    dr5chrome Member

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    You can effectively change a films character by the development/chemistry you use. Each film will be different and create its own curve depending on what you throw at it. Nothing is set in stone. Typically; longer development times do better for this kind of push.



     
  6. Gerald C Koch

    Gerald C Koch Member

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    No amount of development or development method can create shadow detail where none exists. If you do not mind empty shadows then you may be happy pushing film. The sample photograph illustrates this point nicely. High sulfite, low alkalinity phenidone developers like Xtol and Microphen can produce a modest increase in film speed of about 2/3 of a stop. They do this by more fully developing the activated sites in the emulsion. But there is a limit as to what can be done. Sorry but 2F/2F is right, you cannot change the laws of physics.
     
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  7. Joe O'Brien

    Joe O'Brien Member

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    Thanks to everyone who's contributed. Could I do anything with pre-exposure? Say I gave the film three or four stops of exposure and then shot my final image, would this achieve similar results as when done to paper? Would I be able to capture shadows with less exposure of the scene? I read about this in Adams' "The Negative", though it was only discussed as a one stop increase there, if I recall.
     
  8. Gerald C Koch

    Gerald C Koch Member

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    There are two ways of increasing the sensitivity of film. There is hypersensitization which is done before and latensification which is done after exposure. According to Glafkides these methods can increase the film speed by 100% t0 300%. However, he goes on to say; "The various methods of intensification are usually critical operations to perform in praactice, since the results will vary not only with the type of emulsion, but also between two identical operations on the same emulsion." I think this sums up why people seldom resort to this type of intensification.

    Probably the easiest method is to hypersensitize the film by exposing it to a dark green safelight. To be effective the light must be of low intensity and long duration. The article I read many years ago described using a Kodak Brownie safelight 7.5 watts with the light output reduced by a half to a quarter at 10 feet. You would have to experiment as to the distance and the time. IIRC, the time was in the range of 10 to 20 minutes. The film must be exposed within a few hours as the effect wears off rapidly.
     
    Last edited by a moderator: Jul 4, 2011
  9. markbarendt

    markbarendt Subscriber

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    The pre-exposure idea works at getting more detail but in the field with roll film I don't know how practical it really is.

    One thing to remember here is that you not just dancing with the film, your dancing with the paper too.

    Steeper, pushed/plus development, film curves intrinsically print fewer zones on a specific paper grade than normal, flatter, curves.

    Changing paper grades can get you a print with a larger range of detail from the film, but as Gerald says, that detail has to exist and the low threshold is controlled by film exposure.

    A second thing to remember is that if you need EI 25000 the lighting probably sucks. Artificial lighting, done well, could probably improve the shot more.
     
  10. Athiril

    Athiril Subscriber

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    I did 51,200 shot, using a push to 6400. The negs were thin and grain is massive, and exaggerated due to the need of increased contrast to get blacks to black and whites to white from the neg (whether you scan or print).

    Rodinal 1+100, 30 secs initial agitation. 2 hour semi-stand, 2 gentle inversions at 40 min then at 80 min.

    25600 will be thin as well. For Rodinal? I'd probably do a pair of 1+100 2 hour semi-stands, not sure where to begin with 1+50, have gotten terrible results standing/semi-standing with 1+50 before for long periods of time.


    The is 6x7cm, Tri-X @ 51,200 push to 6400 (thin negs). There is 2.5 stops of dynamic range. The water reflection has detail, but I threw it out via contrast instead of burning it in. More dynamic range if you count into the highlights.. but that's a fruitless exercise, so I do not count that.

    Everything has detectable contrast (detail), apart from the black bushes to the right and black landscape area.

    So you're likely to get 3-3.5 stops of dynamic range if developed well for 25,600, not counting extension into the highlights.

    My feeling is you will get different results on different rolls of Tri-X of different unexpired ages.


    However the 2 hour semi-stand is useful for just flogging out some Tri-X @ 1600-6400 to get usable results over a large push range.
    [​IMG]
    Tri-X 51200 Test #1, Beach Night by athiril, on Flickr
     
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  11. markbarendt

    markbarendt Subscriber

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    What did you print that on Athiril?

    You make a great observation about the narrowness of the range in the scene.
     
  12. Joe O'Brien

    Joe O'Brien Member

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    Anthril, can you tell me what you mean by pushing to 51,200 and shooting at 6400?
     
  13. 2F/2F

    2F/2F Member

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    EI 50,000 means seven stops underexposed with Tri-X. This means (assuming incident exposure, in which a middle tone is placed as a middle tone) anything not at least two steps brighter than a middle tone at the scene of exposure has no chance of even being pushed, no matter what you do; it has fallen entirely below the threshold of sensitivity of the film. The things that are two steps or more brighter than a middle tone can be pushed. Though as mentioned, the things that fell higher than others will be pushed more than those that fell lower.

    Developing for EI 6400 in one way of looking at it means that a tone that fell one step below middle gray upon exposure was pushed four stops up to the edge of high-toned detail and texture with development.

    But, since that it nearly impossible, it probably means using the same developing procedure he uses when he rates the film at EI 6400.

    Stand development adds density to the low tones, but it doesn't increase the film's sensitivity to light. How could it? Developer has nothing to do with a film's threshold of sensitivity to light. That is set by the film's design. Stand development cannot pull texture and detail out of thin air (i.e. from things that fell below the threshold of sensitivity for the film upon exposure). It can help to boost what is there in the lows, in terms of both density and local contrast. But then again, so does a simple push using standard agitation. Stand development might be used in an underexposed situation that was high in contrast, while a simple push might be used in an underexposed situation that was low in contrast.
     
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  15. Athiril

    Athiril Subscriber

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    I pushed to 6400 in development, this was one particular shot on the roll that went out to 51,200, most of the roll was EI 6400, with a couple of extra underexposed shots.

    markbarendt: I didn't bother having someone print it for me.

    Extra development can pull extra detail out. Making the assumption that all developable detail is attained at box speed with N processing is a folly. Then there is the case of how many stops in reflectivity your darkest subject/surface in the scene is below the chosen exposure.


    If I take an example of the top of my head, Kodak 5201 50D, if you know it records 4 stops below the chosen exposure on a straight line before even hitting the toe at the given processing and speed rating. You could spot meter your darkest detail and underexpose that reading for the same ISO (50 in this case) by 4 stops.




    iirc, last time I tested, high pressure sodium street lamps are around ISO 1600, 1/30th-1/60th f/1.4, though citys are brighter than that. So the Rodinal 2 hour semi-stand lets you walk around the city at night hand held and develop the various speeds you'd invariably end up shooting.

    iirc, reciprocity effect at ISO 25,600 will kick in start at 1/60th for Tri-X, so for hand held situations there ended up being little point to it.
     
  16. BetterSense

    BetterSense Member

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    I find this all very amusing when people start talking about images they shot "at" some ridiculous E.I. It's all very silly, and meaningless. I understand massive underexposure and desperate pushing, but don't try to pretend that you can quantify the actual exposure with an E.I.
     
  17. markbarendt

    markbarendt Subscriber

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    So, I take it that your example is a negative scan.

    Can we assume also that you tweaked the scanned file a bit electronically to wring out that extra detail?
     
  18. michaelbsc

    michaelbsc Member

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    This looks good. I have been trying to get exactly look for a few night shots under street lights.

    Did you meter a particular detail with a spot? Or average metering?

    Got a link to more like this?

    MB
     
  19. Murray Kelly

    Murray Kelly Member

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    Jerry, I've seen and been told that about the latensification with green light, very dim and very far away. Clair Senft uses it with her Imagelink-HQ and a peroxide latensifier too.

    Nobody has ever told me why it has to be a green light, the peak of human light sensitivity. B&W film is sensitive over a wider range as you know, so why green? TIA
    Murray

     
  20. E76

    E76 Member

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    I wonder how much of a benefit preflashing the film would be in these extreme situations. Eliminating the toe would help with the shadow detail.
     
  21. Athiril

    Athiril Subscriber

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    I can, it was 7 stops under correct exposure for 400 speed. You can quantify it just like any other exposure, if you cannot quantify that you cannot quantify any exposure at all.
     
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  22. Athiril

    Athiril Subscriber

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    No, it is just setting black and white points, nothing else. You lose a lot of detail on a flatbed scan compared to a print.

    Regardless, lightjet prints are far more relevant for film users, the majority of prints made from film are not from a traditional larger.

    If I were to 'tweak' it I would have restrained the highlights from clipping. You would treat this as a low-contrast neg in an enlarger and get the same result above, though not the same since a print is reflective with better blacks and monitor backlit with better whites.
     
  23. Nicholas Lindan

    Nicholas Lindan Advertiser

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    Pushing works best with uniformly lit low contrast subject matter. Unfortunately, most pushers try it with very contrasty lighting like street lights or stage lighting and the results are (to my sensibilities) execrable. Stage and street lighting should be pulled - Tri-x exposed at ASA 50 and underdeveloped by 50%.

    I think the reason for using 'green light' is convenience: most older photographer's still have their Brownie safelight kit with the dark green filter dome. It gives a good consistent source of very dim light.
     
  24. 2F/2F

    2F/2F Member

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    Of course pushing works best with low contrast subject matter. That is almost always ideal if you must push.

    But in the real world, where pushing mostly takes place out of necessity for a hand-holdable shutter speed, things are highly variable and usually completely beyond our control. Try rating your Tri-X at EI 50 shooting a performance hand held in contrasty (but very dim) light, and you will find that you have zero or close to zero usable shots, due to motion blur and/or camera shake and/or missed focus combined with lack of D of F. The occasional shot that might work will be one in which motion blur works well in the picture. If you could shoot it at EI 50, you wouldn't be thinking about pushing anyhow, so I don't understand the reason for that suggestion unless discussing shooting on a tripod...and again, why would you underexpose 6 or 7 stops if on a tripod?

    If you underexpose your shots and push the film, you incease the density and contrast in the areas where it really matters most – the mid tones – and you get usable shots, which is the goal. You may give up ideal shadows and highlights in order to gain acceptable mid tones. But that is the choice you make in order to get a shot at all. You can avoid white highlights on the print mainly by not including them in the composition in the first place, and you can also do a lot about them in printing. That is assuming that they are truly unacceptable, which they rarely are to me. Lucky for me, a lot of the subject matter that requires pushing also works very well as high-contrast imagery IMO.

    There is always a compromise made somewhere when you cannot get the ideal exposure, but there is always a least-bad option to take. Trying to force standard technical parameters into a situation that is that heavily non-ideal will lead to no pictures at all. So you may as well not shoot hand held in low light in the first place if you insist on having the standard textbook print as the primary guiding principle. You'll get the same number of usable pictures (zero) and you won't waste your time and money.

    Of course, the key to knowing when to push and when not to push lies in your judgment of the lighting in which you shot. It is hard to make statements about pushing that work for all cases of underexposure. Like I mentioned a few posts back, if you are underexposing in order to get a shot over no shot, you should push differently in different types of light. Stand develop – push the low tones while simultaneously pulling the high ones – for contrasty light, and use normal agitation in low contrast light.
     
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  25. Athiril

    Athiril Subscriber

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    2F/2F - Pushing this high... I don't think there will be consistent results even from testing a controlled situation, 6400 has consistency on the other hand.
     
  26. markbarendt

    markbarendt Subscriber

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    I think the materials and chemicals could be used very consistently.

    What would be tougher is metering and placing exposure at 25000, a push to 6400 being relatively low contrast when compared to a push to 25000, provides a bit more latitude.