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  1. #1
    Ole
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    Enlarger bulb workaround

    I've been struggling for a couple of days now with a particularly dense negative which needs a little burning too. But since my base exposure was almost three minutes, I tend to get bored when it comes to burning in two more stops on the bright bit at the bottom and so on - and that is with the aperture wide open! I'm beginning to think that my lightbulb is about at the end of its life - but finding a replacement 240V 300W bulb for a Durst L138S is not easy.

    So in a flash of inspiration I decided to try something really different: I bought a 15W low-energy bulb! Screwed it in the socket, turned it on, adjusted the placement a bit, and suddenly I had a full stop more light. Then I realised that this is essentially "cold light", and removed the heat filter: Another stop!

    And then I messed around with lenses a little, and ended up swapping the 150mm with a 180mm, and the 200 condenser with a 240. The result was surprising, to say the least: More even illumination, and yet another stop more light. I would have thought the illumination would decrease, since the condensors illuminate the whole 5x7" and not just the 4x5" I was printing, but there's no arguing with the EM-10?

    The drawback is the long warm-up time of the low-energy lamp, but since I had exposure times in the minutes anyway I can use a lens cap to start and stop exposure. After all, the 15W "bulb" isn't going to heat the negative much in 10 minutes, compared to what the old 300W bulb did...
    -- Ole Tjugen, Luddite Elitist
    Norway

  2. #2
    Schlapp's Avatar
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    Five green stars to you Ole :-) Knew it could be done

  3. #3
    David A. Goldfarb's Avatar
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    Sounds great. I see a Metrolux in your future.
    flickr--http://www.flickr.com/photos/davidagoldfarb/
    Photography (not as up to date as the flickr site)--http://www.davidagoldfarb.com/photo
    Academic (Slavic and Comparative Literature)--http://www.davidagoldfarb.com

  4. #4

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    A company here in Italy is running ads for bulbs that are instant on. I've seen one and it's much faster then normal bulbs. Might not be instant but good enough I think.

    A 15 watt bulb out did the 300w? Must have been nothing but heat out of the big bulb.

  5. #5
    David A. Goldfarb's Avatar
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    We have bulbs in our apartment that are "instant on," but they still have some ramp time until they stabilize.
    flickr--http://www.flickr.com/photos/davidagoldfarb/
    Photography (not as up to date as the flickr site)--http://www.davidagoldfarb.com/photo
    Academic (Slavic and Comparative Literature)--http://www.davidagoldfarb.com

  6. #6
    Whiteymorange's Avatar
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    Sometimes, "instant" is a relative term.

  7. #7

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    The one I saw visually had no delay. Not that means much. But I figure if you're looking at 30 second exposure any delay will be a non-issue.

  8. #8

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    3 mins exposure even with a 300W bulb! Sounds like those negs need the equivalent of a thermic lance or small controlled nuclear explosion. Both have great light outputs but read the safety instructions carefully!

    pentaxuser

  9. #9
    BarryWilkinson's Avatar
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    Ole,

    Maybe you could leave the bulb permanently on and fit a shutter to your enlarging lens?

    Barry

  10. #10
    Dave Miller's Avatar
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    Quote Originally Posted by BarryWilkinson View Post
    Ole,

    Maybe you could leave the bulb permanently on and fit a shutter to your enlarging lens?

    Barry
    Which is the cold cathode solution?

    Tungsten filament lamps convert about 95% of the electrical energy directly to heat, so don't be surprised at the higher output of the fluorescent lamp.
    Regards Dave.

    An English Eye


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