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Thread: How fast can an enlarger shutter be fired?

  1. #1

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    How fast can an enlarger shutter be fired?

    Hey,

    I was recently given some pieces from an HK 877 enlarger, including the behind the lens shutter. I don't have a need for the shutter, because I'm using LEDs for my enlarger build, but the thought crossed my mind that it might be possible to use the shutter for a 12" aero ektar. Do any of you know how fast these shutters can be actuated?

    Thanks,
    Ethan
    Click image for larger version. 

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    [crap iphone photo for reference]

  2. #2
    Tin Can's Avatar
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    Re: How fast can an enlarger shutter be fired?

    Looks like a solenoid Packard

    I only have air bulb Packards which can vary from 1/15 on instantaneous
    image

  3. #3

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    Re: How fast can an enlarger shutter be fired?

    Quote Originally Posted by Tin Can View Post
    Looks like a solenoid Packard

    I only have air bulb Packards which can vary from 1/15 on instantaneous
    that is essentially what it is. seems more robust than the old packards I've seen though

  4. #4
    Tin Can's Avatar
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    Re: How fast can an enlarger shutter be fired?

    image

  5. #5

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    Re: How fast can an enlarger shutter be fired?

    You'd have to experiment, but I have my doubts you'll be able to make this fast enough for, say, something like 1/100. 1/10 and thereabouts, probably not a problem. But faster than that and you'll likely run into excessive wear issues due to the weight of the blades etc. These are just not engineered to be fast.

  6. #6
    Tin Can's Avatar
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    Re: How fast can an enlarger shutter be fired?

    Why fast enlarger shutters

    I aim for for 15 second or more exposures for dodge and burn

    I have metal blade Packard made for solenoid
    image

  7. #7

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    Re: How fast can an enlarger shutter be fired?

    As an electric model most likely that is a #5 and only offers time exposure, not instantaneous.
    Thanks, but I'd rather just watch:
    Large format: http://flickr.com/michaeldarnton
    Mostly 35mm: http://flickr.com/mdarnton
    You want digital, color, etc?: http://www.flickr.com/photos/stradofear

  8. #8

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    Re: How fast can an enlarger shutter be fired?

    A linear solenoid is not an efficient device... The force would need to start instantly, proceed quickly/evenly to open fully, remain open for a given time interval (dwell), then reverse quickly/evenly (with an opposite equal force) to close, then device to reset to allow a another cycle to happen... That's asking a lot for one operating cycle!!!

    The "curse" of these type of shutters is linear activation... If force was applied by a rotary actuator, the force would be "circular", meaning the opening & closing force would be the same force, without requiring the force to reverse (wasting time/energy) to apply a counter force...

    But linear force could be much more efficient if combined with a rotary force (think of a steam locomotive, where the linear force from the steam pistons pushes the drive wheels) but in reverse where a wheel pushes a linear mechanism (like shutter blades)... But has to do this at "mousetrap" speeds... :-(

    But good as a open/close device for non-fractional slow speeds!!!

    (This was hard to explain, so sorry...)

    Steve K

  9. #9
    Tin Can's Avatar
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    Re: How fast can an enlarger shutter be fired?

    I tried toy Radio Control servos as the were cheap

    Too slow

    https://www.pololu.com/category/21/m...cal-components
    image

  10. #10
    Drew Wiley
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    Re: How fast can an enlarger shutter be fired?

    Interesting. I wonder about the intended purpose for that shutter to begin with. In color printing work, the warmup phase of a halogen bulb, as well as the final afterglow, which in fact can affect cumulative color balance, can be trimmed off by means of a precise shutter. The amount of time in which that occurs is so brief that it becomes a non-issue with exposures of 8 to 10 seconds of longer in most cases, and is automatically offset with modern feedback-controlled colorheads. But in this case there's something relatively primitive involved, and possibly engineered for sake of some kind of graphics application. Any specific theories out there?

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