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Thread: Possible light source for 8X10 enlarger

  1. #1

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    Possible light source for 8X10 enlarger

    This new product looks like it could be a good light source for existing or home-brew 8X10 enlargers. It has three "contrast grades" built in. I have a 5000K tube in my Beseler cold light head and I have it "zeroed out" to grade 2 VC with a 30Y Rosco gel. I add more yellow to reduce contrast. To increase contrast I replace with 10Y, then no filter, and then start adding magenta. If this new panel has enough output for enlarging it could be very useful.

    http://www.omegabrandess.com/products/Braun/10320

  2. #2
    Randy Moe's Avatar
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    Re: Possible light source for 8X10 enlarger

    The price is right.

    Let us know how it works.

  3. #3
    Eric Woodbury
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    Re: Possible light source for 8X10 enlarger

    With only a 10W power source, this source is bright enough for direct viewing, but I'd guess 3 or 4 stops short of sufficient output for projection. This is only my educated guess. YMMV.

    ew
    my picture blog
    ejwoodbury.blogspot.com

  4. #4
    Peter De Smidt's Avatar
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    Re: Possible light source for 8X10 enlarger

    I'm afraid I agree with Eric. You might consider using a light meant as a photography light instead of a slide viewer, something like: https://www.bhphotovideo.com/c/produ...orm_ls_1s.html
    “You often feel tired, not because you've done too much, but because you've done too little of what sparks a light in you.”
    ― Alexander Den Heijer

  5. #5
    Randy Moe's Avatar
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    Re: Possible light source for 8X10 enlarger

    Just to obfuscate, here is my 2014 big head experiments. I used only 20 watts. The Fotar was sold to a guy who HAD to have it this year just before I almost moved the monster. It is the best 10x10 chassis I have seen and owned. I have 3 other designs in hand. But I did not like the Fotar counterbalance cabling design and excessive ballast. It was perfectly in alignment without adjustment, as checked by the laser gizmo.

    Not sure if this thread has the lightbox experiments. http://www.largeformatphotography.in...=1#post1100925

  6. #6

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    Re: Possible light source for 8X10 enlarger

    Quote Originally Posted by Eric Woodbury View Post
    With only a 10W power source, this source is bright enough for direct viewing, but I'd guess 3 or 4 stops short of sufficient output for projection. This is only my educated guess. YMMV.

    ew
    Agree. I think my LED light source is near 20 watts for 5x7", and it`s ok but not so powerful, at least for big prints. If this one is 10 watts, for 8x10" it`s also my guess that you could need quite a few minutes of exposure to print a negative.
    Also, I don`t see the point of having color temperature control, and the price seem to me way off for such product. Mine was made for less than EUR 30, and similar sized ceiling lamps for room illumination use to cost no more than EUR 40-60 around here.
    Excuse me if I`m a party pooper, just my sincere opinion.

  7. #7

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    Re: Possible light source for 8X10 enlarger

    An earlier post on a different thread mentioned that his Beseler 8x10 used 12x12" filters. I don't know if that is true, but that might be a consideration -- and 12x12" VC filters can still be obtained. I cut some down to 7x9" for my CB7.

  8. #8
    Eric Woodbury
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    Re: Possible light source for 8X10 enlarger

    True about color temperature. With white LEDs, one is shifting a lot of energy to a useless part of the spectrum (red) and then using inefficient filters to get the contrast control. Better to start with 'royal blue' and green LEDs.

    A good resource for building your own is LEDsupply.com. Good prices and reasonable shipping policy. Look at the kits for grow lights. I wouldn't use one straight-away, but see what they've done and adapt to your needs. They have triplet star LEDs in royal blue and green, bolt-on heat sinks, power supplies, etc. I'm working (slowly) on one now of my own design using their LEDs and heatsink. 9 + 9 blue/green LEDs. Good for over 100W. Mounted up for use with 5x7. I'm suspicious it is too bright by at least 2 stops, but I have not printed with it yet. I've designed the controller, but still need solder the parts together. Simple to build. All analog, so the number of connections is minimal. I'll keep you posted and I'm willing to share design. I even have the LTSPICE (analog circuit simulation tool, free) file for the adventurous.

    Keep up the good work.
    --ew--
    my picture blog
    ejwoodbury.blogspot.com

  9. #9
    Peter De Smidt's Avatar
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    Re: Possible light source for 8X10 enlarger

    Eric's approach has a lot of merit. I look forward to seeing the finished project!
    “You often feel tired, not because you've done too much, but because you've done too little of what sparks a light in you.”
    ― Alexander Den Heijer

  10. #10
    Eric Woodbury
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    Re: Possible light source for 8X10 enlarger

    ...and if it doesn't work out, grow your favorite plants inside. Dual use.
    my picture blog
    ejwoodbury.blogspot.com

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