Converting Vivitar E32 Enlarger to LED Bulbs, any tips?

Discussion in 'Darkroom Equipment' started by harlequin, Dec 11, 2017.

  1. harlequin

    harlequin Member

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    Dear APUG Members,

    I am re-building Vivitar E-34 for 35 and 21/4 enlarging, all glass condensors cleaned,
    all other components cleaned and lubricated, El Nikkor 80mm and Computar 50 2.8 lenses
    are ready for action.

    a) I am thinking of replacing opal lamp with LED's?
    b) What color temp should I be looking at 3200k or 5000k?
    c) Watt equivalency? I think the factory bulb was 75w what would be the equivalent light output?
    d) Any surprises, any papers work better than another, I mostly use Ilford RC Pearl/Glossy.

    Many thanks for your input on this....

    Harlequin
     
  2. 1kgcoffee

    1kgcoffee Member

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    a) Great idea. By using LED you will eliminate heat production. LEDs do not flicker like fluorescent and provide consistent light
    b) around 5000, but anything cool blue is good. Let the filters sort out the light.
    c) If you like to do dodging and burning, then the lower the better in my opinion. I like 40 watt equivalent
    d) Ilford is a great paper. Stick with them for now...
     
  3. Mainecoonmaniac

    Mainecoonmaniac Subscriber

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    If you only plan to print black and white, color temperature is not super critical unless you plan to use Ilford filters to change contrast. Then 3200K would be a better choice. I would run a test between the old tungsten bulb and the new 32K led bulbs and make note of the difference.
     
  4. ic-racer

    ic-racer Member

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    Since this is a condenser enlarger, it projects the image of the top of the lamp. Look at ways you can get a nice uniform surface, may need a piece of uniform diffusion between the lamp and the first condenser.

    For example this would not work:
     

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    Last edited: Dec 11, 2017
  5. 1kgcoffee

    1kgcoffee Member

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    Wouldn't you want something closer to a pure white? 3200 is closer to yellow and will produce a lower grade without filters
     
  6. Mainecoonmaniac

    Mainecoonmaniac Subscriber

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  7. John Koehrer

    John Koehrer Subscriber

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    Tungsten is around 3200 K and from the time of the Vivitar most everything was pretty much based on that type lamp.
     
  8. M Carter

    M Carter Member

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    The graded contrast filters we're familiar with (Ilford, etc.) are based on using a 3000-3400k-ish (tungsten) light source. There's a fair amount of info on the web of people who've tried daylight (5000-6000k) light sources and had issues.

    Most common enlargers don't use a pure-white light source - they use tungsten bulbs, until you get into the flo-tube soft lights and so on (no expert on those myself).

    LED lights get more color accurate every season - I've switched my corporate interview lighting to LED - my key light is equivalent to about 1000w of daylight (or 2000w+ with a full-CTB filter) and the color rendering is great - and it's cool enough to handle and fits in a medium softbox. Pretty amazing stuff. But I think much more attention is going into pure 5500k lighting at the pro end, and there are now 100w 2-3" lens fresnel-type fixtures that could be modded to fit enlargers (100w of LED is a lot of lumens). You'd likely need a full CTO gel if you found that tungsten was needed for enlarging.

    I'm watching this stuff closely - beyond my video gigs, I'd be interested in an LED solution for my enlarger that had a lot of kick - currently use 250w tungsten bulbs but those may be an endangered species for all I know.
     
  9. mnemosyne

    mnemosyne Subscriber

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    A frosted standard (not filament type) LED bulb of around 3000-4000k should work for variable contrast paper. For graded paper, the cooler the better, I would reckon.

    As has been reported and shown here, typical "warm white" (below 3000k, typically 2700k) may have issues reaching maximum contrast with gel filters (because their balance of green and blue light is too far away from the balance of tungsten incandescent light for which the filters were designed for), and it can be expected that too cool (above 4000k) may have issues reaching minimum contrast with gel filters. From my practical experience A 4000k light source will give slightly more contrast with medium filters (#2-3#), but still enables you to reach both extreme grades.

    As for power: a 14 watt (rated as 100 W equivalent), 1500 lumen 4000k ("cool/neutral") LED bulb gives me a full stop more speed on Fomabrom variant than a classic 150 watt tungsten opal lamp. Exposure times will halve.

    Do a comparison test with a tungsten opal lamp for evenness of illumination, contrast and speed. Depending on the light distribution of the bulb itself (narrow/wide) and the lighting system of the enlarger, you may get away without using a frosted screen in the light pass, which can cut down the light considerably (it make about two stops difference in the case of my enlarger).
     
    Last edited: Dec 14, 2017
  10. Ko.Fe.

    Ko.Fe. Subscriber

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    I have E3something Vivitar as the only enlarger I use regularly. Simple, small, white head, something like E32-34. First, here is no heat at all. Second, I went to Home Depot and purchased energy saving opal lamp for few bucks. It just as dedicated enlarger lamp has no writings. It worked fine. I'm just keeping it as spare one.
     
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