LED bulbs vs. halogen?

Discussion in 'Enlarging' started by gattu marrudu, Dec 2, 2009.

  1. gattu marrudu

    gattu marrudu Member

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    Hi,
    I have a DeVere 507 which is a great enlarger, but has some defects: it is very power consuming, it heats up a lot and it need noisy fans to be constantly running, and fades even dichroic filters in the long run, because they are very close to the light source.
    I was wondering if I can substitute its light sources (originally two MR16 24V/250W halogen lamps) with correspondent high efficiency ones.
    Browsing online I found this LED model:
    http://bulbamerica.com/High-Power-5...-3-Bipin-Base-10167-prod.htm?category_id=2604
    It has the same shape, attachment and very close color temperature (3300°K vs. 3250°K of a halogen). I am in doubt about the beam angle, which is 40° but I do not know about the normal halogen. I am not sure if this would make a difference, since the color head has a mixing chamber.
    Has anybody tried something similar? I am from Italy and I would have a hard time getting those bulbs here, so I would appreciate some experienced advice before I get into this...

    Thank you
    gm
     
  2. titrisol

    titrisol Member

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    I have seen those in 12V, and use them for my house.
    The light is good and bright and they do not need "heat up" time like the other energy saving crap-bulbs do

    You may even be able to buy them in red - blue - green and yellow. CHeck in the OSRAM and Sylvania webistes for details
     
  3. bdial

    bdial Subscriber

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    The LED bulb won't put out nearly as much light as even one of your 250W halogens. Also, the bulb you've linked to operates at 12 volts, not 24 which is what your halogens use.
     
  4. gattu marrudu

    gattu marrudu Member

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    Well, of course I might need some adjustments - but on the other end I might as well as retire the 500-pound deVere power supply.
    Luminosity is an issue instead. The model I have linked to has much less of the lumen power (260 lm) as the 250W halogen (340 to 500 lm). The most powerful one seems to be this one: http://www.elationlighting.com/pdffiles/mr16-5w-gu10.pdf (300 lm).
    One question: is the luminous flux (lumen) a reliable factor to evaluate printing times?

    gm
     
  5. ic-racer

    ic-racer Member

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    High power leds still get hot. They may be a little more efficient but in power draw, but they will still need a hefty power supply.

    Those that you have linked to are going to be way underpowered. A 250W halogen MR16 lamp can output 15,000 lumens.

    Not sure about the dichoric filter problem. I just tested my 2000W dichro head that was in a busy commerical darkroom since 1990 and there is no evidence of fade of the filters based on color meter testing.
     
  6. gattu marrudu

    gattu marrudu Member

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    Oh, I thought I had read that a 250W halogen can give about 500 lumen... forget the LED then.
     
  7. Dave Pritchard

    Dave Pritchard Member

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    Good decision. LEDs are usually rated in terms of intensity, not total light output. They are wimpy if compared to a halogen, especially a 5W LED for a 250W halogen.