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  1. #11
    cliveh's Avatar
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    I don’t see why an LED lamp shouldn’t work. In general I have replaced some room lighting with these and a 7 Watt LED is as bright as a 50 Watt. They also look whiter and are much cooler. Students don’t just have enlargers on for longer periods of time when dodging etc. They often just leave them on and leave the darkroom. You could cook an egg on some of those enlargers after a few minutes. I have never tried an LED bulb in an enlarger, but it may be worth experimenting.

    “The contemplation of things as they are, without error or confusion, without substitution or imposture, is in itself a nobler thing than a whole harvest of invention”

    Francis Bacon

  2. #12

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    The LED bulbs cost three times as much as a normal enlarger bulb over here and have the individual LED's clearly visible - not like the very smooth blob of light which a condenser enlarger is expecting to 'see'. Most practical option would probably be to simply buy a few of the correct rating bulbs, and also check there is nothing blocking the cooling vents I suppose.

  3. #13

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    Quote Originally Posted by Newt_on_Swings View Post
    If I get a chance I would like to try out the CFL and LED options and test it, but I have a feeling that those bulbs are just not frosted/opal covered enough to eliminate hot spots in a condenser setup. As well as the potential difficulties with using vc papers. I really thought someone at least had tried this with one of their enlargers.

    I can try this next time with a CFL bulb if you wish. I'd imagine I will have some challenge because of the time lag for coming on full strength and some after glow after it's turned off. As to LED, I'm concerned about the spectura VC papers/filters require. It'll be an interesting experiment that I don't mind doing myself.

    Somewhere on APUG, there was a post from someone who made his own "cold head" with LED matrix.... I remember he used two different colors and ultra-violet.
    Develop, stop, fix.... wait.... where's my film?

  4. #14
    Newt_on_Swings's Avatar
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    Well I was reading into the possibility of CFLs but even with the newer hybrid instant on types, they still take up to 30 seconds to reach full brightness, so I think they are pretty much out of the question.

  5. #15

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    There was some discussion some time ago on using CFL's. As I recall the method most used was to keep the light on all the time, and control the exposure with the lens cap or a shutter.
    I have a couple of LED bulbs that look like they could work in an enlarger, they have a pretty dense white plastic dome over the LEDs. Haven't tried it for that, however, as my enlarger doesn't have a screw base lamp.

  6. #16

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    Quote Originally Posted by bdial View Post
    There was some discussion some time ago on using CFL's. As I recall the method most used was to keep the light on all the time, and control the exposure with the lens cap or a shutter.
    I have a couple of LED bulbs that look like they could work in an enlarger, they have a pretty dense white plastic dome over the LEDs. Haven't tried it for that, however, as my enlarger doesn't have a screw base lamp.
    Yes, what we did with "cold lights" a long time ago.

    Take care that whatever you use, it puts out light of the correct color temperature for the paper in use. LED I have seen are very blue, ok for graded paper or to get max contrast ONLY on VC. For low contrast on VC, you will need 2800 K wave lengths, ie yellow, to be available.

    There may be warm LED available now. Go to Home Depot and check out their display.

    Like to add fluorescents are spiky in spectrum and not continuous so there could be missing wave lengths that you need. Split grade printing might be the answer.

  7. #17
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    Swap Opal Incandescent Bulb with LED Bulb?

    Just a quick update, I got a pair of the opal 75w bulbs from B&H and ran the enlarger for 15min with it on and it only got to a warm level so very safe for my students who got a chance to print with it today. Nice crisp prints with its factory lenses stopped down. The brand of lenses was also Mars branded. I am still on the lookout for a nice bright LED alternative though and will report back once I get some time to shop around.

  8. #18

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    Quote Originally Posted by Newt_on_Swings View Post
    If I get a chance I would like to try out the CFL and LED options and test it, but I have a feeling that those bulbs are just not frosted/opal covered enough to eliminate hot spots in a condenser setup. As well as the potential difficulties with using vc papers. I really thought someone atleast had tried this with one of their enlargers.
    If you still want to go the LED route, possibly the instructor in the shop class (if your school has one) could cut a piece of translucent plexiglass for you to mount at the base of the lamp housing, or rest on top of the condensers. May help with the hot spots.

    Also, If you are interested, I posted on the topic of VC papers and an LED bulb with some measurements. My net, at least for the LED source that I was using, is that the LED does change the characteristic curve of exposure vs density a bit, but not enough to rule out their use on a practical basis. Especially if these are students learning for the first time. More seasoned printers would probably apply more scrutiny.
    http://www.apug.org/forums/forum37/1...-vc-paper.html
    Last edited by jlpape; 03-08-2013 at 05:32 AM. Click to view previous post history.
    Regards,
    Jim

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