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  1. #1
    stormpetrel's Avatar
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    DIY enlarger LED head calibration

    People designing their own enlarger LED head might be interested by this post I wrote in the "smoking solder iron" group about LED head calibration.

    http://www.apug.org/forums/groups/sm...libration.html

    Dom

  2. #2
    RobC's Avatar
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    Quote Originally Posted by stormpetrel View Post
    People designing their own enlarger LED head might be interested by this post I wrote in the "smoking solder iron" group about LED head calibration.

    http://www.apug.org/forums/groups/sm...libration.html

    Dom
    So that's what digital imaging is all about

  3. #3
    stormpetrel's Avatar
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    Nothing to do with digital imaging...

  4. #4
    ic-racer's Avatar
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    With all that data you could have a feature with a probe that you could put on a test print to measure a value. That value could then be the value that won't change when you increase or decrease contrast.

  5. #5
    stormpetrel's Avatar
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    Yep, this will be one of the next upgrade (detailed at the end of the thread).

  6. #6

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    Nice work!

  7. #7
    Steve Smith's Avatar
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    When I built my LED enlarger head, I decided that I didn't need to know what actual grade it represented. Just more or less contrast.

    I had plans to build two PWM power supplies with a control which varied from full green at one end to full blue at the other... but like a lot of my ideas, I haven't got round to it yet!


    Steve.
    "People who say things won't work are a dime a dozen. People who figure out how to make things work are worth a fortune" - Dave Rat.

  8. #8
    RalphLambrecht's Avatar
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    Quote Originally Posted by stormpetrel View Post
    People designing their own enlarger LED head might be interested by this post I wrote in the "smoking solder iron" group about LED head calibration.

    http://www.apug.org/forums/groups/sm...libration.html

    Dom
    why would the process be different bedifferent than any ither light source calibration?
    Attached Files
    Regards

    Ralph W. Lambrecht
    www.darkroomagic.comrorrlambrec@ymail.com[/URL]
    www.waybeyondmonochrome.com

  9. #9
    RalphLambrecht's Avatar
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    Quote Originally Posted by Steve Smith View Post
    When I built my LED enlarger head, I decided that I didn't need to know what actual grade it represented. Just more or less contrast.


    Steve.
    for quality printing you want to knowthe actual grade and it isn't difficult to do
    Regards

    Ralph W. Lambrecht
    www.darkroomagic.comrorrlambrec@ymail.com[/URL]
    www.waybeyondmonochrome.com

  10. #10
    ic-racer's Avatar
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    Quote Originally Posted by RalphLambrecht View Post
    why would the process be different bedifferent than any ither light source calibration?
    He calibrated for a whole series of different gray values (rather than a single middle gray of the standard Ilford filter set).The possibility exists to pick any value in a test print to remain unchanged during a contrast change. To do this with standard color head calibration one would need a whole series of different tables.

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