Instructions for Luna Pro enlarging attachment

Discussion in 'Darkroom Developing and Printing' started by J D B, Dec 26, 2003.

  1. J D B

    J D B Guest

    I own a Luna Pro SBC. I recently came into possession of the
    enlarging attachment, but no instructions. Can anyone help? Thanks!

    JDB
     
    J D B, Dec 26, 2003
    #1
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  2. I use mine to measure maximum black in the print. I measure the amount of
    light coming through the film base based on test strip to determine how long
    an exposure is required to reach maximum black. Set your enlarger to make an
    8"x10" print. Make test strip with your paper and developer say at f8 or
    f11. Make series of exposures increasing the time with each block by adding
    say two seconds (you don't need film for this part). Then process the paper
    for full development 1.5 to 3 minutes. You do not want to control print
    density by underdevelopment. The first block on you test strip that doesn't
    show any further darkening is maximum black. By measuring the amount of
    light coming through the film base you can vary the amount of light by
    adjust the f-stop and keeping the exposure time constant. Very easy way to
    make enlargements of different sizes (and aid to cropping).
     
    Sheldon Strauss, Dec 27, 2003
    #2
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  3. J D B

    Guest Guest

    I have one with the instructions. I will skip the attachment instructions, I
    think you only want the operating instructions.

    <quote>
    How to operate the attachment

    Focus the negative critically on the enlarging easel and determine the desired
    composition. Place the Luna-Pro with the Attachment flat on the easel so that
    the square measuring window is within the most important section of the
    projected negative; the surrounding area [white area around the measuring
    window] will facilitate this considerably.

    Shift the measuring window to one of the darkest areas still showing adequate
    detail if the projected image, i.e. an area which is to be light with still
    distinguishable details in the positive. In other words - you expose for the
    high lights.

    Film speeds, diaphragm stops, shutter speeds and EV values as normally set or
    read on the Luna-Pro are meaningless when elnarging. You are now working only
    with the needle deflection on one of the upper linear scales. The needle
    reading will serve for the determination of the Calibration Value which leads
    to correct exposure. This value is established as follows:

    Adjuct the enlarging lens to your ususal "working f-stop". Place the Luna-Pro
    with the Enlarging Attachment window under the decisive area (as indicated
    above). Now read the needle deflection of the Luna-Pro. If - as sometimes is
    the case - the needle does not come to rest on a scale line, open or close the
    enlarging lens [diaphragm] slightly until the needle is exactly on a scale
    line (for example: 15). This slight adjustment will make all subsequent
    operations more convenient and reliable.

    Remove the meter from the easel and make a test print (step exposure) in the
    accustomed manner; develope normally and select the best exposed strip. The
    exposure of this strip (for example: 20 seconds) becomes the calibration value
    for the combination of needle deflection, grade of paper and time of
    development - in this case 20 seconds for needle deflection 15.

    For correct exposure of any other enlargements, using the same grade of paper,
    simply adjust the enlarger lens opening to obtain the needle deflection 15.
    For future reference, note the calibration "20 sec - meter 15" on the box of
    enlarging paper.

    naturally, other papers, or papers of other contrast grade, have a different
    sensitivity and require different exposure. When relative exposure information
    is not available from the paper manufacturer, you simply stablish the vatious
    calibrations yourself.

    Scale adjustment
    Occasionally, the enlarging lens may not be opened wide enough or closed down
    enough to reach the standard needle deflection. In that case, you simply
    settle on a different needle deflection and adjust the exposure time
    correspondingly, keeping in mind that each step UP on the scale halves the
    calibration value, each step DOWN doubles it. For the "20 sec - meter 15"
    calibration given as an example here the corrections would be:

    Scale (needle): 13 14 15 16 17
    Exposure: 80 40 20 10 5 seconds

    <end of quote>

    There is a short follow up on color materials but in my opinion you are not
    likely to use the very rudimentary instructions since they basically require
    no change in the filter pack.

    After copying all of the above I noticed the "SBC" in your message so I went
    to e-bay and looked up one of the Luna-Pro SBC meters. This is not the same
    meter I have and the instructions above may or may not be correct for your
    meter. Hopefully it may get you started.

    Best of luck

    Bert
     
    Guest, Dec 27, 2003
    #3
  4. J D B

    Guest Guest

    Follow up:

    Here is the meter I own. The instructions were for the enlarging attachment
    for this meter.

    Bert
     
    Guest, Dec 27, 2003
    #4
  5. J D B

    J D B Guest

    Thanks to all who responded.
    Cheers!
     
    J D B, Jan 4, 2004
    #5
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