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  1. #1
    stradibarrius's Avatar
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    Enlarger exposure time??

    I am about to try to print my very first B&W print. I am using Ilford Ilfospeed RC Deluxe #2 grade paper.

    I am going to develop it in Dektol.
    First I am going to make a test strip but I am wonder approximately how long the expose the paper with the enlarger. I know the test strip will help me get it closer, but where do I start...1 min...45 sec...???
    "Generalizations are made because they are generally true"
    Flicker http://www.flickr.com/photos/stradibarrius
    website: http://www.dudleyviolins.com
    Barry
    Monroe, GA

  2. #2
    Vaughn's Avatar
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    I try to aim for around 20 seconds. Long enough to do any dodging and not too long for burning. The other consideration is trying to use the middle f/stops of the enlarging lens to keep the image as sharp as possible.

    Have fun!

    Vaughn
    At least with LF landscape, a bad day of photography can still be a good day of exercise.

  3. #3

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    I usually start with an aperture of f11 and use an expired sheet of paper to do 5 sec for six intervals. You should find a reasonable exposure somewhere in that area. If not, the neg may be too dense or too thin.

    -Fred

  4. #4
    Nicholas Lindan's Avatar
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    Try the following:

    Take a half-sheet of photographic paper and place it in the important part of the photograph. Close the lens down 3 stops.

    1. Make a 5 second exposure;
    2. Cover up about a quarter of the paper with a sheet of cardboard and make another 5 second exposure;
    3. Move the cardboard to cover half the sheet and make a 10 second exposure;
    4. Move the cardboard to cover three quarters of the sheet and make a 20 second exposure.


    This will give you a set of exposures at 1 stop intervals from 5 seconds to 40 seconds - ie 5, 10, 20 & 40 seconds.

    If the whole sheet is too light then open up the lens 2 stops and make a series at 10, 10, 20, 40 second intervals for total times of 10, 20, 40, 80 seconds.

    If the whole sheet is too dark then close down the lens 2 stops and make a series at 2, 2, 4, 8 second intervals for total times of 2, 4, 8, 16 seconds.

    Either pick the best strip or make a new strip at some reasonable time intervals around your best guess. If, say, it looks like the best exposure is between 20 and 40 seconds then expose the paper for 20 seconds and cover it up by fifths making additional exposures of 5 seconds each, giving you exposures at 20, 25, 30, 35 and 40 seconds.

    There is no particularly wrong way to make test strips.

    You may want to adjust the aperture on the lens so your printing time is between 10 and 30 seconds. The best performance from your lens will generally be between 2 and 4 stops closed down from full open. If you have a very good lens the best performance may be at only 1 stop closed down. Aperture and time can be a trade off - for very small prints where there is a lot of light there isn't much harm from stopping the lens down 4 to 6 stops to get a reasonable printing time.

    The most expedient and accurate results are from making strips at equal fractional-stop intervals. f-Stop timers have a feature that generates the correct times for making such test strips automatically.
    Last edited by Nicholas Lindan; 02-18-2009 at 08:27 PM. Click to view previous post history.
    DARKROOM AUTOMATION
    f-Stop Timers - Enlarging Meters
    http://www.darkroomautomation.com/da-main.htm

  5. #5
    jmxphoto's Avatar
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    Am I the only one using a projection print scale?
    http://www.freestylephoto.biz/41621-...on-Print-Scale

    Pick an F top (usually F11 here), slap that on the spot you're most concerned about, or just smack in the middle, and pop the timer on for a min. When it's processed you can read the correct exposure time off the wedge you like the best. I've even used it to split grade. Seems to work for me so far.

  6. #6
    BetterSense's Avatar
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    Very interesting. So is that a transparency? It's a bit hard to tell from the photo.

  7. #7
    Vaughn's Avatar
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    I have one of those floating around here somewhere -- but the simple test strip (using about 1/3 sheet of paper) tells me so much information that I have never felt the need to use one of the projection print scales. I suppose it is just a matter of what one is use to doing. A carefully placed test strip gives me info on exposure, contrast (over-all and local) and how much burning and dodging will be needed. But then I also always make a straight work print, too.

    Vaughn
    At least with LF landscape, a bad day of photography can still be a good day of exercise.

  8. #8
    MattKing's Avatar
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    The Projection print scale is a wonderful thing. I think Kodak invented it, but like Kodachrome, they must have let the patent lapse. .

    It is hard to describe in words, but essentially it is a bunch of neutral density filters (segments) that show the result if you use an exposure time that corresponds to that segment. In other words, if you expose an image through it (for the 60 second time recommended), the segment that results in the best range of densities on your test print, will correlate with an exposure time that will give you an excellent starting point for your exposure tests.

    I think they are a much more useful aid for BetterSense, then they could ever be for someone like Vaughn, simply because they are great for getting you into the "ballpark", and, well, Vaughn is probably already in the "ballpark" anyways .

    If you cannot find one, BetterSense, send me a pm - I may have a couple extra of these, which you could have for postage.

    Matt

  9. #9

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    The method I have started using recently (Can't remember where I picked it up) was a piece of genius and transformed my test strips effectively in to "stops" of light for each part of of the strip. This meant I could think of modifications to expsoures in terms of stops of light just like a camera.

    Take the strip and place onnthe easel and expose all of it to the negative for 2 seconds. Then cover up a small part of the strip and expose for another two seconds. Cover up a little more of the strip and expose the uncovered part for 4 seconds, cover up more of the strip and expose the uncovered part for another 8 seconds. cover more and expose for 16 seconds etc...

    What you end up with is a test strip which is exposed as 2,4,8,16,32,64,128 etc....you can take it as far as you think your negative needs it. If you think your chosen strip is half a stop too dark then you can take half a stop off. Voila!

    The pain is that you need to keep changing the timer, but I have found it saves me more paper and time since it covers a wider range of exposures and allows me to judge what is needed from a dodging/burnig point of view.

    Rgds, Kal

  10. #10
    Vaughn's Avatar
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    You have me confused, Kal (Matt was right I am in the ballpark -- usually way out in left field...LOL!). But following your instructions, it seems like I would get strips of 2-6-14-30-62-126, etc. I must have missed something, since it works for you.

    It seems like it would be easier to set the timer to 20 seconds (or whatever time one likes to work with) with the lens closed down to the smallest aperature, and then expose each strip separately, opening up the lens one stop each time...if one wanted each step to be one stop apart.

    Vaughn
    At least with LF landscape, a bad day of photography can still be a good day of exercise.

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