What's the dynamic range of B&W film?

Discussion in 'B&W: Film, Paper, Chemistry' started by film_guy, Nov 29, 2007.

  1. film_guy

    film_guy Member

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    Anyone know the dynamic range of B&W films like Tri-X, BW400CN and XP2 Super? And how does one maximize the huge dynamic range properties of B&W film?
     
  2. dancqu

    dancqu Member

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    Maximise the contrast of the subject, exposure,
    and development. Dan
     
  3. DrPablo

    DrPablo Member

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    Tri-X probably has the biggest range of the three.

    You don't need to maximize the whole dynamic range of B&W film unless you have a high contrast subject. With normal development, you should have full detail from zone 3 through zone 7, or 5 stops, using B&W film, and retain textures in zones 2 and 8 -- so that's about a 7 stop range with normal development. But if you're willing to pull 2 stops in development, then you can capture detail over a 9 stop range. And if you read about people like Bruce Barnbaum who use extreme compensating developers, you can pull like 7 stops and capture detail over a 14 or 15 stop scene brightness range (which one hardly ever encounters).

    The best way to make sure you maximize the DR of B&W (and color print) film is to make sure you don't lose shadow detail. Survey your scene, place important shadows on zone 3, and then adjust development to place important highlights on zone 8. That's a fairly simplified zone system, and it takes advantage of the film's DR.
     
  4. Harry Lime

    Harry Lime Member

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    Does using a divided developer like Barry Thornton's 2-Bath buy you anything?

    Also how much of a gain do you really see from a 'full speed' developer like Xtol or DD-X over something like D76?

    thanks.
     
  5. CPorter

    CPorter Member

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    I'm assuming by dynamic range you mean the range of tones between pure black and pure white (which, in ZS terms would be negative densities that yeild print tones from Zone I to Zone IX). I would say that it is maximized when the negative is developed to a contrast range that is closely aligned with the exposure scale of the paper you are using.

    Straight line films today may not reveal a shoulder on the curve until a log E density of 3.3 (Zone XII) or more. Even so, you must hold the negative density range to within the printable density range of the paper. The capabilities of the film is buffered by the limitations of the paper, so you must maximize the capabilities of the paper by careful exposure and development of the film.

    Chuck
     
  6. JBrunner

    JBrunner Moderator Staff Member Moderator

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    How much dynamic range? It's kind of like asking, "How big is a rock?" It is very difficult to quantify film performance in the way people have come to expect from being exposed to the marketing claims on the boxes that contain certain types of imaging hardware.

    We test so allot for specific situations because film possesses such a wonderful range of responses under different conditions and procedures, so in order to answer your own question you would have to have a particular exposure and developing regimen in mind for a specific stock.

    In general one can state certain properties that a particular stock may posses under general circumstances, but if you are looking for a specific answers, you need a specific protocol, and getting that answer requires carrying through with that procedure, unless you are lucky enough to be in contact with someone who already has, and even then, YMMV.

    The short answer regarding the dynamic range of B&W film is "usually more than most persons can print"
     
    Last edited by a moderator: Nov 29, 2007
  7. donbga

    donbga Member

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    A simple BTZS test will answer your question about most any B&W film you are interested in.
     
  8. Jim Noel

    Jim Noel Member

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    Chuck is certainly headed in the right direction.
    The range of the films today are far greater than the papers most people use. It doesn't matter if the film has a tremendous range if the papers can not reproduce it.
    That is the reason many workers print on Pt/Pd, albumen, salt and so on - they are able to produce a far greater range than silver gelatin.
     
  9. gainer

    gainer Subscriber

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    Dynamic range must be defined before it can be used. The ancient philosophers had a rule: define your terms. I saw several posters apparently using several definitions.

    When you photograph a scene, you are trying to capture a certain range of scene brightness in such a way that you can display it on paper or on a screen. All transparent materials can show by transmitted light a scene of much wider range than can be shown realistically on paper. If you are planning to print on paper, it does little good to capture a scene brightness range that is much greater than paper can show. We can fool the eye to some extent, as painters have been doing for eons, but by and large the maximum brightness range film can possibly record depends on its maximum density. The maximum range in practice also depends on the developer. The same film will have a different maximum gradient in each developer and concentration. HP5+ in Rodinal at 1+50 dilution cannot achieve a gradient greater than 0.61 according to AGFA. I don't remember what its maximum density is, but let's say it is 3.0. A rough guess at its maximum scene brightness range would be 4.9 log units. The actual brightness ratio would be greater than 75000 to 1.

    Now the question is how to extend that range. If the maximum density the film can provide is 3, we do NOT want to jack up the contrast by choosing a different developer. That would cause a shorter brightness range to use up all the film's density range. If you are hell bent on extending the scene brightness range you can record, you could develop to a CI of 0.3 and stretch it out to about 10 log units. Where you will get such a scene to photograph I do not know and probably would rather not know.

    Paper can show a maximum reflection density on the order of 2 log units.
     
  10. film_guy

    film_guy Member

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    Yikes, can someone explain in layman's terms to me about all the technical terms spoken here? lol

    Thanks guys for the thorough explanations, although I understood only 1% of what's being talked about.

    Another question - if I use BW400CN or XP2 Super, and have a lab develop them, I guess I'm at their mercy when it comes to wanting prints with high dynamic range?
     
  11. JBrunner

    JBrunner Moderator Staff Member Moderator

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    Are you talking about something that looks like the "HDR" computer gimmick?
     
  12. Ole

    Ole Moderator Staff Member Moderator

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    I know, and have needed to do it...

    I shot a partial solar eclipse, four exposures at 15 minute intervals, on APX100, developed in Windisch' extreme compensating pyrocatechin developer. To my surprise I could see not only details in the foreground (shadowed) shrubbery, but I could also see sunspots! I don't know what SBR that translates to, and I'm not really sure I need to know.
     
  13. gainer

    gainer Subscriber

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    I was privileged to photograph a total eclipse from my front yard in Newport News VA in 1970. I prepared for days testing ND filters and making a jury rigged telescope-camera kluge. Everything went well except my FP shutter hung up half way across. I don't remember for how long, but I was able to print the image by some really strong dodging, or burning, whichever you want to call it. Of course, at the moment of totality the thing you want to see it the diamond ring, and I got that. If I can find the print, I'll post it. It was on display at the Mariner's Museum for quite a while.
     
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  15. film_guy

    film_guy Member

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    No, I wasn't talking about the HDR technique from Photoshop. I was looking at Ansel Adam's images, and the tonality he got from B&W film he used were astounding. I was wondering if that's possible without using C-41 B&W film.
     
  16. JBrunner

    JBrunner Moderator Staff Member Moderator

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    It's perfectly possible. The films, developers and papers we have available today can be had in equivalent or better than what he had to work with.

    *Hint- its not the materials....or the camera... or the lens....
     
  17. film_guy

    film_guy Member

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    Sorry, what I meant was is this possible using C-41 B&W film.
     
  18. David Brown

    David Brown Subscriber

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    This is just my opinion, but ...

    Probably not.

    For one thing, you likely aren't going to get Ansel Adams type tonal ranges out of 35mm film. (others may disagree) But even if possible, Adams, and many others (including a few of us :wink:) have worked very hard to learn and CONTROL the materials and only achieve the results you desire by doing the work themselves. You will never get the "look" of an Ansel Adams by having the drugstore develop and print your pictures.
     
  19. gainer

    gainer Subscriber

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    A famous violinist of old, Fritz Kreisler I believe, would give a recital and at the end, after playing with magnificent beauty, he would smash the violin. He told the horrified audience it was not his famous Strad but one he got at Sear Roebuck for $1.98. (That could be done in those days.) I think it was that way with Adams. What he produced would have come out of him no matter what tools he had. Interesting that he was a very skilled musician, is it not?


    A more recent violinist, Isaac Stern, when complimented on his playing, said "I left no tone unSterned. To a lady who complimented him on his fine violin, he said "Madam, would you play a passage on it for me? I never get to hear it from a distance." When someone asked Michelangelo how he did such fine sculpture, he said "If I want to carve an elephant, I take a big block of marble and simply cut away everything that doesn't look like an elephent."

    None of us are going to get to be like Ansel by using his tools and materials.
     
  20. sbelyaev

    sbelyaev Member

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    Dynamic range depends on density of the developed film and contrast (gamma). Typically max density is about 3. Lets say gamma is 0.55 than dynamic range is about 13-15 stops.
     
  21. Photo Engineer

    Photo Engineer Subscriber

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    Kodak tests all B&W films in one release process. IIRC it is D76.

    This process is used to get the speed and contrast.

    So, if you accept the fact that a negative film has a contrast of about 0.6 and a dmax of about 3.0 you can plot this on paper to get the latitude in Density vs Log E. It is quite simple.

    A 160 negative film can yield usable pictures from ISO 25 to about ISO 800.

    PE
     
  22. nick mulder

    nick mulder Subscriber

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    [​IMG]

    I read somewhere online :smile:rolleyes:smile: Edgerton used POTA developer for these pix ...
     
  23. nworth

    nworth Subscriber

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    My guess is that the question is about ordinary film with ordinary processing (OK - Zone System processing). The answer is still confusing. The absolute dynamic range is usually huge. Many films show noticeable density changes over 14 stops. However, that range is highly non-linear. It is compressed at both the top and the bottom. The linear part of the range (straight line portion of the curve) is generally about 7 stops (128X), but it varies from film to film. You can look up the curve for an individual film to see how it responds. Because of the way film speed is measured, you don't have much room to play at the bottom (toe) end. Most modern films also have a fairly short, gentle toe. At the top end (high exposure), most films will show at least some difference in density in what would be Zones X-XI or even Xi-XII. It isn't much, but it can be very useful. Some films may go all the way to Zone XIV before they reach a real DMax, although you will have a hard time seeing it. (The difference between Zone I and Zone XIV is 8192X.) Older style films have more modest ranges than the modern emulsions.
     
  24. RobC

    RobC Member

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    I suspect that there may be a misunderstanding on the part of the questioner. It seems he wants to know if a c-41 B+W film can produce the sort of results adams achieved. The answer is that possibly it could. But you must understand that a fine black and white print with a full range of tones from deep black to pure white is not a simple function of what dynamic range a film has. It is a combination of the subjects dynamic range plus the films dynamic range plus the film development plus the papers dynamic range plus the printing filtration used (if any) plus the paper developer plus your interpretation of negative when printing.

    using your c-41 film with its standard development at a lab introduces a constant (maybe variable) to only one part of the equation but a very important part of the equation. Since that part will be out of your control you must be extremely careful to select subjects with the correct dynamic range to fit that constant and use the printing parts of the equation to fine tune the results.

    That basically means you must shoot when the lighting levels and contrast between shadows and highlights are optimum for your film otherwise you will lose something at one or other end of the scale which you could control to a certain extent if you were doing your own film development.

    [edit] And Also your subject selection and whether your subject lends itself to producing stunning printed image[/edit]
     
    Last edited by a moderator: Nov 30, 2007
  25. JBrunner

    JBrunner Moderator Staff Member Moderator

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    While I think it could be possible to achieve the aims the OP seeks with 35mm chromogenic stock, I do think it would be a pretty hard wall to beat ones head against. It would be seriously easier to just shoot LF B&W. If he is considering it as some kind of technical challenge, I would be very interested in regular updates to the quest.

    As Rob said, much more is in play than the characteristics of the film, and I would add to his list the most important thing, and that is the part that escapes magic bullet chasers everywhere:

    You can mimic every bit of the materials and equipment somebody you admire uses, and it won't get you anywhere. St Ansels images came from his heart and head, and the same hammer and chisel in other hands won't reproduce it, nor will a quest for a magic bullet.

    However, if you want to understand AA's approach, and procedure, he was kind enough to leave behind a staggering amount of instruction, in regard to how he worked. You will notice that the underlying premise of all of it presupposes control, and indeed much of it is specifically devoted to teaching how to control the process. Starting out with a stock that puts processing out of your control pretty much stops your journey at the beginning, and because chromogenic film is designed to forgive exposure errors, you won't be learning as much about exposure, either.

    Ansel's process for exposure and printing is a little cryptic at times, but pretty easy to follow in the end. It is a skill set well worth learning, and can help you succeed in your own vision. If Ansel had used chromogenic film, I'm sure we would have his take on it. He did, in later years shoot a fair amount of smaller format film, and his opinions on what worked and didn't work are documented.

    In his words, "You don't take a photograph, you make it"

    Hope this helps,

    Best

    j
     
    Last edited by a moderator: Nov 30, 2007
  26. nworth

    nworth Subscriber

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    Tri-X certainly has the range to attain the results Adams did - and more. Many have used this film with zone system processing, as Adams described, to obtain fantastic results. Most other modern films are almost as good used that way, although some seem to change contrast somewhat less in response to development changes. The film data sheets are your best guide here. You can get somewhat more range out of traditional films by using compensating developers or special low contrast developers like POTA. Some films do better with these than others, and the curve distortions and local effects they produce may not be to your liking.

    The chromogenic films pose different problems. The linear dynamic range of these films is huge - at least 10 stops. That is more than enough to deal with just about any subject. The problem comes in printing these films. Zone system development controls are not used in processing the film. (Has anyone done any experimenting here?) The negatives are dye images. The Ilford product prints well on ordinary paper, usually requiring only a little more contrast than silver negatives. But you do need to adjust the contrast in printing to match the scene, rather than using zone controls. If you pre-visualize in the Adams fashion, you need to take the printing process into account as it applies to this film, which means changing your thinking some. The Kodak chromogenic product produces a very low contrast dye image that must be printed either digitally or on color paper. Once again, you must take the printing process into account when making the exposure. My experience with these product is limited but good. They are capable of outstanding images. But I think it will take some disciplined experimenting to hone a technique for them equivalent to the zone system. It's certainly possible, but I don't have the dedication for it.