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  1. #11
    Bob Carnie's Avatar
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    Sanders McNew had a thread going that though not the same result I believe it to be the same cause.
    Insufficient agitation in the initial stages of development.
    Uneven development over flat skys or grey backgrounds*in his case*.
    I don't think this is a exposure problem or camera problem.
    Increase agitation and rotation of the film in the first 15 seconds of development.

    To test for even development photograph a nuetral grey card and work on your agitation and rotation methods. I belive the problem will solved.

  2. #12

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    Thanks, Bob. I never thought I had a problem with agitation, but perhaps I do. I'll certainly try something different. I usually do 5 twisting inversions per minute. Would you recommend constant for the first 30 or 60 seconds, or just more vigorous agitation? Or both? Thanks.

    Jmal

  3. #13
    percepts's Avatar
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    Quote Originally Posted by jmal View Post
    I have a question or two about the tonality of my prints. When I'm shooting anything with a lot of sky, the sky always appears uneven in its tone, despite the fact that it appears consistent to the eye. Is this just a difference between what my eyes see and what the camera sees? The reason that I ask is that it often appears to lighten when it's next to a darker object/tone. Is this a characteristic of film in general? It doesn't seem to happen in my non-landscape shots. I have attached an example, though it's hard to see exactly what I'm talking about. 35mm Tri-X in DDX. Straight print with no dodging or burning, but cropped to square. http://www.flickr.com/photos/71163977@N00/510294056/ Thanks.

    Jmal

    Take a sheet of paper and expose it to a mid tone on your baseboard with no negative in the carrier using aperture you used for the sample you gave. Develop normally. This will tell you if your enlarger produces even light or not.

    Sky is usually siginificantly brighter towards the horizon due to fact light is passing through much more atmosphere nearer the horizon and haze and atmosperic moisture create the lighter tones.

    Main light source also has this effect to left or right of image and can be dramatically emphasized by printing at higher contrast. Also emphasized when sun is low in sky.

    Could also be your camera lens but I doubt it. Could also be your enlarger lens.

    Shutter? I doubt it.

    Uneven film development also a possibility.

    Uneven paper development also a possibility.

    You will just have to try and illiminate the possibilities by testing methodically.
    Percepts,
    An old dog learning new tricks...

    Black and White Landscape Prints

  4. #14
    Bob F.'s Avatar
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    If you have another camera body (or can borrow one) try shooting with that and with your Nikon on the same subjects. Then compare the two sets of subsequent prints. That should tell you if it is your camera or your processing where you need to look closer.

    Good luck, Bob.

  5. #15
    percepts's Avatar
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    take a look at this image and tell me if the two halves are constant tones or does one side have a light gradient towards the join?

    Click image for larger version. 

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    then copy the image and measure the tones with your graphics software and see whether what you see is actually what is there.

    p.s. this image has never been near a camera or any developer of any sort. It is computer generated.
    Percepts,
    An old dog learning new tricks...

    Black and White Landscape Prints

  6. #16
    jeroldharter's Avatar
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    I second the enlarger condenser theory.
    I assume that contact prints don't have the same problem?
    Jerold Harter MD

  7. #17
    fhovie's Avatar
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    When you twist a spool in developer - the action is much greater in the center than near the edges where the fluid is slowed down by the rim. I use tank(s) that can be inverted. When I agitate, I invert a few times - more slowly with larger tanks with larger volumes of fluid and then twist a few times so there is no pattern in the motion of the fluid. - Not that this is your problem ... your image is darker in the center which might hint that it is light fall off either from one of the lenses in your process or from the light source.
    My photos are always without all that distracting color ...

  8. #18

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    Thanks for the replies. I'm going to test my enlarger, my agitation, and shoot some gray cards. We'll see if I can either eliminate or reproduce the problem.

    Jmal

  9. #19

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    Quote Originally Posted by percepts View Post
    take a look at this image and tell me if the two halves are constant tones or does one side have a light gradient towards the join?
    You are correct of course. It does appear that there is a light gradient near the join, but in fact there is not. Using the dropper tool in Paint Shop Pro, anywhere you measure to the right of the join, the numbers are the same: R=94, G=94, and B=94. To the left of the join the numbers are 0 for R, G, and B. So yeah, your reply does illustrate an optical illusion. Very clever. It is possible that that the OP is also seeing an illusion, but I can't be sure. Truth be told, we know very little about the image. We have no information about the time of day, the condition of the sky (overcast overhead with clearing at the horizon), position of the sun, etc. I don't think it is a development problem, and I really don't think it is a problem with the enlarger's light source.

  10. #20
    skahde's Avatar
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    Can you see this difference in densitiy in the neg? What does the print look like if you turn it by 90° in the enlarger?

    My initial response was uneven developement. About 10% more density at the edges turned out to be pretty normal for me when I got a densitometer and started using it. If you burn in the edges as a standard or print small it is not even a problem and noone will notice it but you seem to have more of a difference than 10%.

    Best

    Stefan

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