Sorry, another film testing question

Discussion in 'B&W: Film, Paper, Chemistry' started by ccross, Apr 13, 2012.

  1. ccross

    ccross Member

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    Hello all,
    *
    I would appreciate some help regarding a subject that I’m sure has been done to death here, but my searches here have not turned up the answers I am looking for.

    I have never been much for film testing, so I have been happily shooting away based on manufacturer’s recommendations and a few suggestions here. *But, I think I have reached the point now where I would like to explore a bit deeper. I have a copy of Les McLean’s book and thought I would give his film testing method a try. *

    I have exposed and developed the film as described and am left with the negative and contact sheets in front of me wanting to understand what I am looking at.

    The particulars:
    Three rolls of Ilford Delta 400 film, rated at 400, each exposed at +3,*+2,*+1 stops, meter reading,*-1,*-2 and*-3 stops of the same scene. *

    Films were*processed in Ilford ID-11.
    -*N time of 14:00 min.
    -*N+1 time of 16:45 min.
    -*N-1 time of 11:45 min.

    Contact sheet was printed on Ilford multigrade RC paper at grade 2 and processed in Ilford Bromophen.

    I know this is the subjective part but when I am looking at the contact sheets there are several that look like they would be printable negatives. *The one that stands out to me as having the best looking shadow detail is the one overexposed by*+1 and developed N-1. *It also shows pretty good highlight detail.

    Am I interpretting it correctly that my film speed should be closer to 200 and my development time for normal development should be in the eleven minute range? *Or am I missing the point?

    Thanks in advance for any input.

    Craig
     
  2. Bill Burk

    Bill Burk Subscriber

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    Without reading up on Les McLean, off the cuff, I'd say it sounds like a reasonable finding from a round of black and white negative film testing for grade 2. Go shoot with it this weekend at 200!

    The "overexposure" ensures adequate shadow detail, and the corresponding "underdevelopment" keeps the highlights from being so dense they become difficult to print.
     
  3. Rich Ullsmith

    Rich Ullsmith Subscriber

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    You are not missing the point. And congratulations on your great discipline in running tests and keeping notes, something I myself have never managed to profit from.

    My own method is similar. Tx400 @320, 10m @ 75f is "standard." If the light was generally harsh or contrasty, then stand develop for the last few minutes. If the light was "flat," then let stand for a few minutes past standard development. Not very scientific, but it gets me close.

    Sounds like you have a pretty good idea. Thanks for reminding me to go find that McLean book.
     
  4. Mahler_one

    Mahler_one Member

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    HI Craig: I agree with Rich....you are to be congratulated for the testing. However, IMO, the entire process of "film testing" can be so much easier to complete. Simply consider contacting Fred Newman at The View Camera Store who will help with your film testing, and completely remove any subjective bias. As you might know, Fred will expose your film using a step wedge, and return such to you for processing in your own darkroom using your own methods. You will develop for 5 different times, and return the film to Fred. Fred reads the results on his densitometer, and returns the results to you via a graph that will easily allow you to understand the various developing times that should be used for various subject brightness ranges ( SBR ). Meter the shadows and the highlights, determine the SBR.
    From the graphs, given an SBR for a particular scene, you will know what speed to rate your film. Set the meter at that speed. Next, meter the scene (the shadows ) using the film speed indicated....done. Expose, then develop for a time based upon the SBR according to a graph that is derived from your testing. The process appears to be so much harder than it is when writing about such, but in practice takes about a minute or less. Once your testing is completed your are DONE...and you no longer have to worry about anything else but correct metering.

    Please feel free to PM me for additional questions or details.
     
  5. ccross

    ccross Member

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    Wow, thanks for the quick responses you guys.* I've been reading so much about testing lately that I'm giving myself a headache, so I appreciate the comments and am glad I'm not confusing myself too much.

    I've been putting off testing for about two years now, but I've been noticing more and more that when I am printing I seem to be trying to get more contrast into my images.* When I finally stopped to think about it, it dawned on me that my neg's to date are probably a bit flat for the look that I want.

    Mahler_one, honestly before your post I'd never heard of Fred Newman and wasn't even aware a service like that existed (yes, I live in my own little bubble, but I have my camera so I'm happy).* I'd like to take my testing a little bit further so I can get a better understanding of what is going on, but might take you up on your advice down the road.

    Thanks again for the input guys.

    Craig
     
  6. Bill Burk

    Bill Burk Subscriber

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    Hi Craig,

    Getting a better understanding is always a good thing that comes from film testing, possibly the ultimate reward for all the hard work.

    Fred Newman provides a great service and when you add up the hours he might save you, the price is great.
     
  7. jeffreyg

    jeffreyg Subscriber

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    Craig,

    A testing method that has worked for me is somewhat similar to what you have done. You should be able to do it with one roll of film.

    With the lens cap on run off a couple of exposures. Then take the +/- exposures of an 18% gray card filling the entire frame (don't worry about focusing). Develop the film according to mfg's time/temp. When fully processed, wash and dry take the leader part that you did not expose and at the enlarger height for an 8x10 enlargement and f8 make a test print a couple of seconds each as you move the card. Process that print and when dry see where you can tell a difference from pure black. Cut pieces of printing paper and label with pencil on the back. Print each negative at the time you determined a change in the black. When processed and dry find the one that is closest to 18% gray and use that for your personal ISO. Shoot various subjects at that ISO. When you print you can see if some tweaking with contrast etc is needed. When shooting you can also tweak if necessary but this is a good standardizing technique.

    IMO it's best to keep certain factors constant and make changes to fit a particular situation.

    http://www.jeffreyglasser.com/
     
  8. RalphLambrecht

    RalphLambrecht Subscriber

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    i agree with sending a note to fred newman. he uses the phildavis method of teting filmthat i also use and advocate in my book. it is the simplest and most reliable method i came across in 30 years of fil testing
     
  9. Mahler_one

    Mahler_one Member

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    Craig: I neglected to add that you can fully implement the Phil Davis method of film testing into a comprehensive easily mastered system ( called, "ExpoDev" ) that is inexpensive, and which is now available as an APP for an iPhone. One loads the film testing data from Fred into the program, meters ( incident metering is best for the Beyond The Zone System approach, but reflected metering and the Zone System can be used as well ), and after entering the data into the program on your iPhone, you read the correct exposure at various F stops, etc., etc. Moreover, the program tells you the ideal developing time for the paper that you are planning to use such that your negative can more exactly "fit" the characteristics of the paper. Fred can help you through the details. The attendant costs are quite reasonable, and the time saved in materials and effort will be be paid back many times.

    Go to BTZS.org and have a look around.
     
  10. Mahler_one

    Mahler_one Member

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  11. RalphLambrecht

    RalphLambrecht Subscriber

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    Customizing Film Speed and Development 215
    2. Fast and Practical
    Here is another way to arrive at your effective film speed and customized development time. It is a very practical approach, which considers the entire image producing process from film exposure to the final print. The results are more accurate than from the previous method, and it requires three simple tests, but no special equipment.
    a. Paper-Black Density Test
    This test will define the minimum print exposure required to produce a near-maximum paper density. Make sure to use a blank negative from a fully processed film of the same brand as to be tested. Add a scratch or a mark to it, and use it later as a focus aid.
    1. Insert the blank negative into the negative carrier.
    2. Set the enlarger height to project a full-frame 8x10 inch print and insert contrast filter 2 or equivalent.
    3. Focus accurately, then measure and record the distance from the easel to the film.
    4. Stop the lens down by 3 stops and record the f/stop.
    5. Prepare a test strip with 8, 10, 13, 16, 20, 25 and 32-second exposures.
    6. Process and dry normally.
    7. In normal room light, make sure that you have at least two but not more than five exposures, which
    relative log exposure [lx·s]
    base+fogtransmission density ISOfilm speed1.30 0.80 ±0.050.10Hm   = 0.615
    the proper exposure and development of the film. This requires adjustment of the manufacturer’s film speed (or ‘box speed’) and development suggestions.
    In general, advertised ISO film speeds are too optimistic and suggested development times are too long. It is more appropriate to establish an ‘effective film speed’ and a customized development time, which are personalized to the photographer’s materials and technique. In most literature, the effective film speed is referred to as the exposure index (EI). Exposure index was a term used in older versions of the standard to describe a safety factor, but it was dropped with the standard update of 1960. Nevertheless, the term ‘EI’ is widely used when referring to the effective film speed, and we will accept the convention.
    Still, we ask ourselves: How does one establish the effective film speed and development time to compensate for different subject brightness ranges? An organized test sequence can give you very accurate results, but even a few basic guidelines can make a big difference in picture quality. I would like to show you three different ways, with increasing amount of effort, to keep you from wasting your time on too many ‘trial and error’ methods.
    1. Quick and Easy
    Here is a simple technique, which will improve picture quality significantly and does not require any testing at all. Use it if you dislike testing with a passion, or if you just don’t have the time for a test at the moment. This method can also be used to give a new film a test drive and compare it to the one you are using now.
    For a normal contrast, bright but cloudy day, cut the manufacturer’s recommended film speed by 2/3 stop (i.e. ISO 400/27° becomes ISO 250/25°) and the recommended development time by 15%. The increased exposure will boost the shadow detail, and the reduced development time will prevent the highlights from becoming too dense. For a high-contrast, bright and sunny day, increase the exposure by an additional 2/3 stop (i.e., ISO 400/27° now becomes ISO 160/23°) and reduce the development time by a total of 30%. Stick to the ‘box speed’ and suggested development time for images taken on a low-contrast, rainy or foggy day.
    A negative processed this way will easily print with a diffusion enlarger on grade-2 or 2.5 papers. Just give it a try (fig.1). It is really that simple to make a significant improvement to negative and image quality.
    de
    velopment timefilm speed[ASA]scene contrast-- 2/3- 1 1/3low-normal- 15%high- 30%adjustmentstypical subject brightness rangerainy or foggy daybright but cloudy daybright sunny day
    fig.2 Film exposure and development in accordance with the current ISO standard.
    fig.1 It is possible to make significant improvements to negative and image quality without any testing. Use this table to deviate from the manufacture’s recommendations for film exposure and development according to overall scene contrast.
     
  12. Arkasha

    Arkasha Member

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    Ralph - I'm afraid your post got a bit mixed up. At point 7 above it looks like several sentences are mixed in, and I just can't follow your post beyond that point.
     
  13. Leigh B

    Leigh B Member

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    Hi Craig,

    Your test procedure sounds excellent to me. You certainly don't need any outside intervention.

    Now try making some enlargements to see if your assessment holds up under magnification.

    Remember, you can always burn in highlights if they lack detail on the print, as long as there is detail in the denser areas of the negative.
    You can't add detail in the shadow areas beyond what's on the negative. That's why most folks overexpose by some amount v. the film box speed.

    It appears you came to that same exact conclusion. Congratulations.

    - Leigh