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  1. #21
    BetterSense's Avatar
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    First check with a square to confirm that it is
    a rectangle.
    You can verify that it's a rectangle by comparing the diagonal measurements. They should be the same.
    f/22 and be there.

  2. #22

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    I keep several laser alignment tools on my belt!
    I brake for fixer!

  3. #23

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    Quote Originally Posted by BetterSense View Post
    You can verify that it's a rectangle by comparing the diagonal measurements. They should be the same.
    Let's assume that we have the trapezium ABCD and AB, CD are the parallel sides. If angles A=B and C=D, then the diagonals AC, BD will be equal!
    Last edited by Anon Ymous; 08-30-2009 at 12:30 PM. Click to view previous post history.

  4. #24
    BetterSense's Avatar
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    Correct. That certainly works. But you need an angle-measuring device to measure the angles and see if they are the same. You can compare all four sides of the quadrilateral as well as the diagonals with only a length-measuring device. And since you are only comparing them for equality, it doesn't even have to be accurate (a piece of string etc.).

    I don't even have a square around here, but I certainly have something I can mark with a pencil to compare lengths with.
    f/22 and be there.

  5. #25

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    Oh, you missed my point. I didn't suggest to measure the angles. I just wanted to point out that you can have equal diagonals, without having 4 90 degree angles. If you're going to use diagonals, you need to make sure they bisect each other. In any case, comparing lengths seems the best choice for me.

  6. #26

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    Quote Originally Posted by Anon Ymous View Post
    Parallelogram, or did you really mean trapezium?
    The most common misalignment should produce that.

    Can you misalign an enlarger and get a rhombus
    from a square frame?
    Well you mentioned "the parallel sides" in your post
    so I went with that. Rhombus, trapezoid, from the
    four sides of the negative I can't say how many
    quadrilaterals might be formed.

    I've an Issue of Camera and Darkroom wherein
    an article describes a method of alignment which
    makes use of the trapezoid as part of the
    alignment procedure. Dan

  7. #27

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    Quick Check for Alignment

    Quote Originally Posted by BetterSense View Post
    But you need an angle-measuring device to measure the
    angles and see if they are the same.
    A square or triangle, draftsman's or grade schooler's, is
    needed. Ninety degrees is THE angle. Only TWO checks of
    the internal angles need be made. If the object projected
    is a rectangle and the projected image tests square at
    two corners the enlarger is well aligned.

    The same test will do to confirm progress when actually
    working to align an enlarger. After all, the finale proof
    of alignment is on the baseboard. Dan

  8. #28

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    Quote Originally Posted by dancqu View Post
    A square or triangle, draftsman's or grade schooler's, is
    needed. Ninety degrees is THE angle. Only TWO checks of
    the internal angles need be made. If the object projected
    is a rectangle and the projected image tests square at
    two corners the enlarger is well aligned.
    That's true! And the OP should be more that happy to spend his $100 buying more film and paper IMHO.

  9. #29
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    You guys would over think an orgasm.
    DIGITAL IS FOR THOSE AFRAID OF THE DARK.

  10. #30
    Sirius Glass's Avatar
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    Quote Originally Posted by raucousimages View Post
    You guys would over think an orgasm.
    ROTFLMAO!!



    Steve
    Warning!! Handling a Hasselblad can be harmful to your financial well being!

    Nothing beats a great piece of glass!

    I leave the digital work for the urologists and proctologists.

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