Naling exposure without a densitometer

Discussion in 'B&W: Film, Paper, Chemistry' started by BetterSense, Feb 14, 2009.

  1. BetterSense

    BetterSense Member

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    I haven't started shooting B&W other than XP2. But here's the problem I can foresee. You have three variables of exposure, development, and printing exposure. How can you know if you are underexposing in the camera or underdeveloping? Or over-exposing during printing?

    Even if you give the negatives the 'eyeball' test for dense-ness, if they appear too dense, you still can't tell if it's exposure or developing. Unless you just totally go by the Massive Dev chart as gospel. Do people do that?

    What makes total sense to me, is the method explained by Ken Rockwell of bracketing an entire roll of shooting an OOF 18% grey card. Then measuring the density of the resulting neg, subtracting the density of base+fog and choosing whatever EI is closest to his optimal number. But STILL, if you are developing yourself, how can you know that your development is 'correct'? If it this test turns up showing that you should shoot Tri-X at 200, maybe you are underdeveloping, you know? The only thing I can think is that people really take the development charts as gospel. I can't even think about what you would do without a densitometer.

    Printing is a whole other shootin match, but it would be so much worse if I didn't even know if my neg was proper to start with.

    Sorry for the long post by my scientist brain thinks about these things too much.
     
  2. df cardwell

    df cardwell Subscriber

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    A photographer needs a densitometer like a fish needs a bicycle.
     
  3. Neal

    Neal Subscriber

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    Dear BetterSense,

    It's not as bad as it sounds. Start with a roll of film, bracket two stops each side of box speed, develop per the manufacturer's suggestion and print. Print all of the bracketed negatives of at least one scene. The one with the shadow detail you like is pretty darn close to your personal speed. If you need to print with a grade 4 filter you didn't develop long enough. If grade 2 is too contrasty you developed too long. Be consistent in your agitation. Have fun. Trust me, you will continue to adjust for a long time (if not forever!).

    Neal Wydra
     
  4. drpsilver

    drpsilver Subscriber

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    14 Feb 2009

    BetterSense:

    I can understand your "scientist brain" because I am an chemical engineer that asks similar questions.:smile:

    I you do not have, or have access to, a densitometer there are ways to determine your exposure index (EI) and correct development time. The following is a method that you might consider.

    1. Shoot part of a roll at "box speed" using a gray card to fill the frame of the camera being used. Bracket around (+/- 2 stops) the suggested exposure given by your meter. It is critical that the lighting of the gray card be as uniform as possible.
    2. Develop this portion of the roll for the length of time suggested by the manufacture or some other trusted source.
    3. Print these frames giving just enough exposure to make the "film base + fog" maximum black.
    4. Compare the tone of the frame to a gray card. The frame that matches will be a good approximation of the correct EI. (Recall that a one-stop overexposure approximates a one-stop lower EI.)
    5. Once you have determined your EI repeat steps 1 to 4 using your EI instead of the "box speed". In these trails you will want to vary the development time from above as a starting point.

    You might also as part of your exposure trials shoot a frame at Zone I, II, and III with something that has texture. In this way you can get a sense of what shadow detail will look like at different EI and development times.

    Hope this helps. Good luck with your experiments. Remember to take good notes. I have found that Ansel Adams' books very helpful in understanding how to test films.

    Regards,
    Darwin
     
  5. OP
    OP
    BetterSense

    BetterSense Member

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    So we are taking the manufacturer's suggestions to be, as a starting point, our constant. OK. Also I assume you mean the development times given for the box speed, and not varying them for the one-stop push or pull brackets.

    Using un-filtered MG paper (I think it's grade 2 when unfiltered)?

    It's starting to make sense to me. BTW, where can one get a cheap grey card?
     
  6. Nicholas Lindan

    Nicholas Lindan Advertiser Advertiser

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    I think that may be the problem in a nutshell.

    Set the meter to what the manufacturer says, develop the film in a standard developer like D-76 or ID-11, use the manufacturer's time, temperature and agitation. Use Kodak film with Kodak developer, Ilford with Ilford.

    Everything will come out fine. It's not rocket science. Developing film has been mastered by legions of 8-year olds.

    These first rolls will show you what a properly exposed and developed negative will look like.

    It is the same with baking cake or making a roast: best to follow the cook book instructions, because if you experiment on your very first cake you are going to get a real mess - right?

    Millions of rolls a day are exposed and developed this way and the pictures come out just dandy. It is only the dilettantes who go in for the quest for the Personal EI and Magic Pyro Formulation. APUG is wall-to-wall dilettante, and I count myself among them: I claim you can't time print exposures in seconds... (well, you certainly don't want to if you have a better way). So be careful of the advice you get here, some is geared to post-doctoral levels of abstruseness.

    After you have done a couple dozen rolls by the book then it is time to experiment with different EIs and developing times and what not. These subsequent rolls will show you what wrong exposure and development look like.

    As suggested, you may want to bracket some exposures on your first roll, just so you know what over and under exposure look like and as assurance that the camera and metering are working well. For a normal subject the by-the-book negative should produce the best print, if not then it is time to check out the gear and the technique. Don't fall into a trap such as using an altered EI or developing time to compensate for a slow camera shutter - get the shutter fixed.

    So, don't think - just do. After you have learned how to do, then it is time to think. If you try to think first, well, to put it plainly, you will fail because you don't know enough yet to think to good end - you will just lead yourself far afield in fantasy land.
     
  7. Mark Fisher

    Mark Fisher Subscriber

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    I'm an engineer so naturally I wanted to get everything perfect. I quickly found out that film testing is not exactly why I photograph plus metering (particularly with an in-camera meter) is not particularly exact. so I'd decided to keep it simple.
    I start by rating my film half a stop (35mm) to a full stop (larger formats) below the box speed and develop in something that maintains reasonable speed (xtol mostly). I used to expose at about 1/3 stop below, but I found that my shadows were lacking detail so I'm rating my film a bit slower now. I start development time based on the manufacturers recommendation to get the box speed and adjust from there based on how I am printing. Lately, I seem to be reaching for Grade 4 filters when printing lately so I'm starting to develop about 15% longer. This change has nothing to do with the materials or my meters changing. It has to do with my personal taste in how I want to print. This is another reason to not get too tied up in testing. It really doesn't take too long to get to exposure and development time you like IF you stick to one film and one developer. If you don't, it is really hard to fine tune anything (I learned the hard way!)
     
  8. David Brown

    David Brown Member

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    Beat me to it! :smile:

    The film makers have developed their films and chemicals for good results. Why on earth would they publish data that would give you otherwise? Now, if after you gain experience, you WANT something different - then make changes.
     
  9. MurrayMinchin

    MurrayMinchin Membership Council Council

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    Bracket your exposures for a while and keep notes. Make contact sheets of your negatives printed at normal contrast, developed for the recommended time in your developer and expose them at 'max black time', which is the minimum exposure which results in the negatives clear edge printing as black. As long as you choose scenes with normal contrast they should print with texture throughout. A poorly exposed or developed negative will have no place to hide!

    Before working on a negative I usually make a 5x7 proof print a wee bit shy of max black time, just to find out exactly what I have to work with.

    Murray
     
  10. jnanian

    jnanian Advertiser Advertiser

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    as others have suggested
    bracket your exposures, on as your meter says
    one stop under one over ..
    you will easily see what looks best .

    i had never heard of a densitometer before i came to places like this.
    learn how to shoot and process and print without all that other junk.

    it is pretty much not necessary, unless you are a scientist.

    mr cardwell pretty much said it all ...
     
  11. dpurdy

    dpurdy Member

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    Without a spot meter to read the dark tones you need to incorporate your own judgement into the process. Personally I packed my densitometer away because it was gathering too much dust. I have a piece of film that I know to be AA's Zone 7 taped to my light box for comparison. I judge by eye. Film speed, dictated by threshold of density and shadow detail is pretty easy to see on the light box.
     
  12. tiberiustibz

    tiberiustibz Member

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    I second that.

    How do you tell? Lets see. If the negative looks like you could weld with it it's time to back off the development. For starters shoot it at box speed.
     
  13. MattKing

    MattKing Subscriber

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    The result of over-exposure is different than the the result of over-development when you consider photographs, as compared to tests.

    That being said, the advice about shooting at box speed is good advice.

    When we talk about adjusting the EI you use when you meter, or adjusting the time or temperature you develop at, we are talking about adjustments, not radical changes. Those adjustments are in the nature of fine-tuning, not full scale revamping.

    If when you meter, you have a tendency to include a bit too much sky, then a bit lower EI will be a good idea.

    If you use an enlarger lens with a bit of extra flare, and a diffused light source, then a bit more development will most likely help.

    You probably won't really be in a position to make those judgements, unless and until you are either printing your negs yourself, or are working closely with an experienced printer who can help you with them. Until then, do a little bit of bracketing, and experiment a little bit with development, in the hopes that you can get some results that "sing".

    Hope this helps.

    Matt
     
  14. jgjbowen

    jgjbowen Member

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    If you would like to get this nailed down as quickly as possible, I would recommend you purchase Bruce Barlow's "Finely Focused" book on CD. It comes with a .1 ND filter you can use to determine the proper film speed and a piece of paper with unexposed & Zone VIII tones so you can nail your development time. All the instruction you need is included in this $25 (including postage) book. Once you get the basics down, Bruce includes lots of tips and tricks to help you be more efficient in your photography and a ton of exercises to help you develop your seeing. www.circleofthesunproductions.com

    Good Luck,
     
  15. df cardwell

    df cardwell Subscriber

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    Photography is all about the print. When you have learned what you like the print to look like,
    then you can decide whether the so-called standards which assign numbers to negatives have any meaning or not.

    'Standards' are no more than highly precise numbers with no meaning. YOU decide the look and feel of the print.

    Follow Mr. Linden's advice. Enjoy yourself. When you print, print no more than one negative in a session. You'll find yourself achieving that gratifying equilibrium between your rational and intuitive mind, and with any luck at all, spend a great deal of time framing your pictures to hand on your office wall.

    When one learns to play a piano,
    very little time is actually spent rebuilding the Steinway.


    It doesn't need to be hacked, and improved. In the same way,
    the last thing a photographer needs to do is to become a sensitometrist.

    .
     
  16. CPorter

    CPorter Member

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    A statement like this is a can of worms to some folks, but this can of worms is putrid.

    Photography is no different than anything else, there is always more to learn. The point in time may come when you want to take your level of understanding higher. The very worst thing you could do is to let your own level of understanding be hindered by others. There are two truths, IMO, one, a densitometer is not needed to have fun with photography and to be a good photographer; two, expanding your knowledge base by learning about sensitometry and how to use a densitometer will make you better at your craft and improve your photography. If you have that desire in the future, then go for it.
     
  17. keithwms

    keithwms Member

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    Yep, bracket and do contact prints. Purists will suggest contact prints on graded (as opposed to multigrade) paper. There are definite merits to that. But... and this is a big but, I'd not start that process with xp2. Xp2 is special in some ways, not the least of which it has a box speed that many believe to be a full stop overrated, plus the way it defines contrast in your print is a bit different from how just about any b&w film does that. Also it has a rather unusual highlight rendition, and highlights are of course where you judge the neg density by eye. So it's a bit special in all these aspects. Honestly I have a hard time just looking at xp2 negs and sensing whether the density is optimal; it was a while before I felt I could get satisfactory results with it. It's not uncommon to have that issue with chromogenics and/or stained negs (i.e. developed in the pyros). Xp2 is not as hard to print as bw400cn (due to its mask) but nevertheless chromogenics are in a special category IMHO.

    First and foremost, I'd step away from chromogenics and just shoot some good old b&w first. if you are doing chromogenics because of a scanning workflow, just beware that your scan software can (and does usually) do auto levels and curve adjustments etc. and then you don't learn anything.
     
  18. edtbjon

    edtbjon Member

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    While I havn't read the book I can guess what kind of method Bruce Barlow suggests. It is dead simple and also includes the "whole chain" including the camera and the enlarger, i.e. you are calibrating your system, not only a piece of test film. I was about to write a description of how I've learnt to test EI with a ND .1 filter, but I recon you are better of with the book. (Especially as a Kodak Wratten .1 ND is kind of expensive, and it comes without a 200+ pages book. And no, there's no CD included either. :smile: )

    //Björn
     
  19. drpsilver

    drpsilver Subscriber

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    15 Feb 2009

    BetterSense:

    This is correct. But remember these times are only a starting point.

    This is also correct. You could use a #2 filter if you wish, but the exposure times (under the enlarger) will be longer then unfiltered light. Just be consistent in the methods you use. Most camera stores will sell gray cards (either from Kodak or Delta) at a reasonable cost.

    Remember the "scientific method" that we were taught long ago.

    Regards,
    Darwin
     
  20. Stephen Benskin

    Stephen Benskin Member

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    Most labs (if they still exist) have densitometers, and many will read your test free or for a small charge. Phil Davis also explains how to use a spot meter as a densitometer in Beyond the Zone System. If you want to do it all without a densitometer, the ring around print test works. In fact, it's similar to the type of test where film speed and the concept of photographic print quality originated. It's a lot of work though.
     
  21. ic-racer

    ic-racer Member

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    A useful test is to ensure that a Zone I exposure (ie five stops underexposed) produces a density of 0.1 log (that would be one-third of a stop decrease in light when the negative is held over an exposure meter).

    You can tell. Moderate overdevelopment does not affect the shadows. Severe overdevelopment fogs the shadows and this will show on the unexposed film base. Overexposure affects the shadows but does not affect the unexposed film base. If you are overexposed, then, indeed it is difficult to tell if the development is correct by eyeballing it, but it can come with experience.

    The gold standard is that if the negative prints well, it is developed OK. The densitometer then can be used to give a number (the slope or gamma or CI) to aid in repeatability with other films.