Switch to English Language Passer en langue française Omschakelen naar Nederlandse Taal Wechseln Sie zu deutschen Sprache Passa alla lingua italiana
Members: 71,957   Posts: 1,586,072   Online: 945
      
Page 1 of 2 12 LastLast
Results 1 to 10 of 20
  1. #1
    Max Power's Avatar
    Join Date
    Sep 2004
    Location
    Aylmer, QC
    Shooter
    Multi Format
    Posts
    598
    Images
    5

    Anyone have any comments on Les Meehan's Testing Method?

    Owing to my difficulties with Delta-100 and Rodinal, I was searching the internet for a more consistent and scientific approach to getting a good result with this film/dev combination.

    I came across a web-site devoted to the Zone System made by Les Meehan. On the site, Les has a very methodical write up on finding one's own EI and Dev times. The article is here: Monochrome Film Testing. I have read the article a number of times and it strikes me as being an excellent approach, especially for an amateur like me.

    Does anyone care to comment on how good a method this may or may not be before I launch myself into it? Any practical observations? Anything seem a bit wonky?

    Thank you,
    Kent
    Max Power, he's the man who's name you'd love to touch! But you mustn't touch! His name sounds good in your ear, but when you say it, you mustn't fear! 'Cause his name can be said by anyone!

  2. #2
    mikewhi's Avatar
    Join Date
    May 2004
    Location
    Redmond, WA
    Shooter
    8x10 Format
    Posts
    808
    Images
    9
    Personally, I think it can get pretty confusing to attempt to do a ASA speed test AND a development time test simultaneously. I do the 2 in entirely seperate sessions that can be weeks apart.

    I use sheet film, and I do my ASA tests in a way where I get 6 exposures on a single piece of film. This is enough to determine the correct ASA speed (which is almost always the rated speed of the film - I think modern mfg. techniques have made this test a little redundant, but hey I bought the densitometer, so I'm gonna use it!).

    For 35mm film, I used to buy 12-exp rolls, but I don't think they're made anymore. You can take a 36-exp roll, expose 6 or so frames for an ASA test, open the camera in the dark and snip off the film and process it. Re-thread the remaining film and use the rest of the roll for dev time tests.

    I'd suggest keeping it simple and doing ASA tests seperate from dev. time tests. To read the densities, you can buy a .10 Kodak Wratten Filter. Place the film strip on a light box and then put the filter over the clear areas in between exposures. Match one of the exposures to the combined density of the clear film and the ND filter and you have your Zone I reading, which will tell you what your ASA speed is.

    To read Zone VIII densities, just place the negative over some newsprint in a room with normal lighting (like mid afternoon sun). Look for a density whereby you can just read the print thru the negative and that will be very close to your Zone VIII density. The development time that created that density will be your 'normal' density.

    If you want precision, you can mail me your negatives and I'll read them for you. PM me for this. I've done it for another APUG member and he got his ASA speed of 320 for Tri-X confirmed this way.

    He does make a good point about getting a neutral colored card that is EVEN and SMOOTH in texture and evenly lit. I use flood lamps with diffusers on them for this and I use grey paper from an art supply store. I have seen tests done on a textured surface and the densities are not uniform, so be sure to get the correct target paper. You must focus on infinity, too. Even if you do, a textured surface will not be smooth, so you must get the correct surface - something middle gray.

    I understand his comments about the printing time to get maximum black and many of his warnings are true. However, I use this technique and I believe in it. Most of the errors he points out are due to failure to use common sense. View the black areas under the same lighting you're normally viewing prints under and it's pretty easy to pick out the first max black strip. If you take this strip and light it up with a 500-watt flood lapm, sure you'll see that it is suddenly 'gray' compared to darker strips, but you don't view prints under a 500-watt bulb, do you?

    -Mike

  3. #3

    Join Date
    Nov 2002
    Location
    Melbourne, Australia
    Shooter
    Medium Format
    Posts
    1,013
    I think that there are lots of variations to this vital investigation. Without grinding through the whole thing, I offer a couple of comments.

    I agree that it is difficult to detect the subtle differences in Zone_I exposures on paper. I used a Minolta spotmeter to read negs on a light table which had a fluorescent tube in it. When I got a densitometer, I found it to agree closely. But when I had used other light sources with the spotmeter (for reading negatives) such as bright overcast, tungsten ... I got incorrect numbers.

    The light for your test exposures should be similar to your typical use. Testing with Photofloods and taking pictures with daylight could require a different film speed.

    Personally I have found it easier (though it takes longer) to test for speed first, then development. I would choose an initial dev time somewhat shorter than the usual manufacturers' figures (maybe less 25%), since too much contrast is more often a problem than not enough.

    At the end of the day, when in doubt, overexpose if possible (but not too much, of course)

  4. #4

    Join Date
    Jul 2004
    Location
    fairfield county, Ct.
    Shooter
    Large Format
    Posts
    1,830
    Images
    24

    testing

    Mike-that was a great post. If anyone follows your instuctions they should be able to do the testing in one or two days most. For the ASA test you can also go outside in late morning;find a spot around the house with even lighting and put up a 16x20 mat board or the like. Works just fine as not everyone has lights. Just make sure the light is even; that what is most important. Lastly your point about the redundency of testing is a more up to date idea. Most MODERN films will hold their speed under normal lighting.

    regards, Peter

  5. #5
    Lee L's Avatar
    Join Date
    Nov 2004
    Shooter
    Multi Format
    Posts
    3,244
    They're not as inexpensive now as when I got mine, but I find the Wallace Expodisc a great help for film testing, incident metering with TTL metering on 35mm cameras, and for setting color balance. This is basically a translucent diffusion sandwich that fits over the lens, starting furthest from the camera lens with a plastic triangular prizm diffusion grid, then ND and fine tuning color balance filters, then a translucent milky white plastic. It's inside a plastic ring that's sized to fit specific filter sizes, but I also bought a bigger one that I can just hold up against the front of any lens I have. It's basically a high-tech version of the item Ansel Adams describes for making pre-exposure film flashes, made with two white translucent plastic sheets spaced by cardboard. I made one of those as well. For B&W work, you only need to make sure that the diffusion plastic has no strong color cast. One of the new style polystyrene plumbing pipe caps (not PVC) would work well, about $1.50 for a 4" diameter version where I live.

    The reason that I bring this up here is that you'll never need to be concerned about looking for even illumination for a gray card or big mat board with this kind of setup. All you need is a light source similar to what you'll be shooting under. I use daylight balanced compact flourescent lamps indoors for "outdoor" film testing, and I can set up for any reasonable exposure range by adjusting the lamp-to-diffuser distance. With sufficient diffusion a few mm in front of the lens, and the lens focused at infinity, there's no worry about unevenness of illumination across the frame. Just meter through the diffusion material with a reflectance meter, and the diffusion material in the position relative to the light source that it will have when on the camera. With TTL metering this is a cinch. With a view camera, it's not much more difficult.

    This has saved me a lot of time and trouble over the years. You can also give low level pre-exposures in the field with these diffusers to give shadow detail a boost, and I also flash paper in the darkroom to bring down the highlights using the same method. I don't even have to pull the negative, just hold the diffuser under the lens and hit the timer.

    Lee

  6. #6
    Dave Miller's Avatar
    Join Date
    Dec 2003
    Location
    Middle England
    Shooter
    Medium Format
    Posts
    3,894
    Images
    2
    Quote Originally Posted by Max Power
    Owing to my difficulties with Delta-100 and Rodinal, I was searching the internet for a more consistent and scientific approach to getting a good result with this film/dev combination.
    As one who gets very acceptable results from Delta 100 developed in Rodinal I’m intrigued regarding your results. What problems are you experiencing with this combination?
    Regards Dave.

    An English Eye


  7. #7

    Join Date
    May 2004
    Location
    Florida
    Shooter
    Pinhole
    Posts
    141
    Images
    7
    Mr.Meehan's testing method seems to have been inspired by Fred Picker's method as outlined in The Zone VI Workshop. It's probably out of print now but used copies are still available.

  8. #8
    Max Power's Avatar
    Join Date
    Sep 2004
    Location
    Aylmer, QC
    Shooter
    Multi Format
    Posts
    598
    Images
    5

    Thank you all!

    So far this thread has been really informative and I really appreciate all of your comments; they are helping me to narrow down what my approach ought to be. Your practical suggestions are all really helpful, especially the newspaper trick; I will definitely try it.

    Dave,
    The problem I was having is that when I followed Ilford's instructions for the souping of D-100 in Rodinal, the frames were massively overexposed compared to what I get from the combination of D-100 and ID-11 at 1+1. I used the same equipment, camera, meter, conditions etc, and got very little which was useable. I did the test again at 20% less development than suggested by Ilford and still got overexposure. Thus my quest to find a more soundly 'scientific' approach to the question.

    I hoist my pint to you all,
    Kent
    Max Power, he's the man who's name you'd love to touch! But you mustn't touch! His name sounds good in your ear, but when you say it, you mustn't fear! 'Cause his name can be said by anyone!

  9. #9

    Join Date
    Dec 2004
    Location
    Phoeinx Arizona
    Shooter
    Multi Format
    Posts
    1,343
    For those of us without a densitometer (or a spot meter) or, like me, have a very low threshold for complicated test procedures I use a method that I was taught my the NCOIC of the first military darkroom I worked in. All you need is a Kodak projection scale, a clear piece of film or clear negative of the film you intend to test, a few family members and a day to fuss about.

    The first step to find a time for your paper. Set the hight of your enlarger for a 8X10, put the clear film in the negative carrier, paper (normal contrast) in an easel with the projection scale on top of the paper to be tested. The Kodak projection scale is basically a round step wedge. In normal use is used with a negative to create a test strip, in this case we are looking for the best time that provides a full range a tones from white to black. Set F stop to your usual working apature and pick a time. I normally use 8 seconds as my starting point. Expose the paper and develop at your standard time. After fixing, quick wash dry the test print, for fiber base use a microwave, and inspect the test print. You are looking for white that is paper base and a good black with midtone separation. Too dark another test strip less time, too light darken increase time, and repeat until you find the best time. You can do 2 tests on 1 8X10. Each enlarger lens may test with different times.

    Second step to find the true film speed for you target film and camera. You need a few friends or family members. Find a spot with open shade, have person in dark (black) sweater with some texture, another in a light (white) sweater with some texture. A gray card (optional) is helpful. Set your cameras light meter to 3 stops below the films rated speed. For ASA 100 start with 12. Expose one frame at each 1/2 stop increase so the range is 3 stops below and 3 higher than the rated speed. Develop in your prime developer at the recommended time. After the negatives dry using the same paper and time make a contact sheet, develop fix wash dry and inspect the contact sheet looking for the first frame with texture in the black sweater, this is your shadow detail and that frame is your films true speed for your camera. Each camera needs to be tested. Now look at the highlights and midtones. If your highlights are blocked or muddy you need to find the true developing times for your film and developer combination.

    Same set up, this time expose a roll of film,(or sheets) at your true film speed. In the dark room cut the roll into strips about 4 or frames and load one strip into a tank or develop in a tray. If your highlights were muddy incease the develpment time by 5%, if blocked decrease by 5%. After processing print and inspect, keep increasing or decreasing the development time until you have the highlights that you are looking for.

    Once you have both the true film speed and development time for shooting in average conditions you will get an average (working)8x10 print without needing test strips, as long as the paper, paper develop, film, developer and development times are consistent. Change anything and need to start over.

    Paul

  10. #10

    Join Date
    Jun 2004
    Location
    Portland, OR
    Shooter
    4x5 Format
    Posts
    3,268
    Quote Originally Posted by Max Power
    ...the frames were massively overexposed compared to what I get from the combination of D-100 and ID-11 at 1+1. I used the same equipment, camera, meter, conditions etc, and got very little which was useable. I did the test again at 20% less development than suggested by Ilford and still got overexposure. Kent
    Overexposure is not the same as over-development. If it is over-exposure, then you are going down the wrong trail to solve your problem. The only way to solve over-expsoure is to give the film less exposure.

    So is it really over-exposure, or is it over-development?

    Kirk - www.keyesphoto.com

Page 1 of 2 12 LastLast


 

APUG PARTNERS EQUALLY FUNDING OUR COMMUNITY:



Contact Us  |  Support Us!  |  Advertise  |  Site Terms  |  Archive  —   Search  |  Mobile Device Access  |  RSS  |  Facebook  |  Linkedin