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Thread: An imagined LED enlarger light source for 4x5 -- NEW INFO FOR TECHNICIANS

  1. #31
    Peter De Smidt's Avatar
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    Re: An imagined LED enlarger light source for 4x5 -- NEW INFO FOR TECHNICIANS

    I couldn't care less what you think, Drew. Why bother commenting on my posts?
    “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.”
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  2. #32

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    Re: An imagined LED enlarger light source for 4x5 -- NEW INFO FOR TECHNICIANS

    A standard condensor with a household LED bulb (4000K or above) works perfectly fine. No need to construct or adapt anything. Just replace the traditional tungsten bulb with a LED bulb and off you go. That is, if you're OK with using a condensor enlarger, which I absolutely prefer.

  3. #33

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    Re: An imagined LED enlarger light source for 4x5 -- NEW INFO FOR TECHNICIANS

    It is sometimes difficult to list all the variables that others think of. It seemed to me that when I spoke of replacing my cold head enlarger light source, it would be clear that I use a diffused light source. I wish to keep doing so, after spending many years with a condenser head and never looking back,as they say, after getting the cold light.

    Ben, I have not ruled out the Intrepid, but the building part, as I have said several times, is not something I do well. I doubt that I would be able to make it work, but I may look into it further. I appreciate your idea as well as those of others.
    Philip Ulanowsky

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  4. #34
    Peter De Smidt's Avatar
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    Re: An imagined LED enlarger light source for 4x5 -- NEW INFO FOR TECHNICIANS

    A piece of frosted glass or white acrylic isn't hard to cut.
    “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, Nothing You Don't Already Know

  5. #35

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    Re: An imagined LED enlarger light source for 4x5 -- NEW INFO FOR TECHNICIANS

    Quote Originally Posted by Peter De Smidt View Post
    A piece of frosted glass or white acrylic isn't hard to cut.
    Score it and snap it!

  6. #36
    Drew Wiley
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    Re: An imagined LED enlarger light source for 4x5 -- NEW INFO FOR TECHNICIANS

    A distinction has to be made between units acceptable for VC paper and actual color printing, which seems to be largely wishful thinking at this point in time for LED technology.

  7. #37

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    Re: An imagined LED enlarger light source for 4x5 -- NEW INFO FOR TECHNICIANS

    The last time I spent any time looking at enlarger specs, Reagan was still president, and my father was planning his darkroom-- so if I sound like an idiot, it's by accident, rather than on purpose.

    But these days, I have a 1700 lumen flashlight that runs off of a single rechargeable battery and only has one LED. The LED, a CREE XHP35, is apparently rated for just over 1700 lumens (at max power, which would shorten the life-- at 85C, where they can run indefinitely, is "only" 440 lumens), has a CRI > 90, and available at a number of color temperatures.

    I would think a handful of those, mounted to a quality heatsink with a decent driver behind them, would produce more than enough light to run an enlarger.

    But that's just speculation on my part.

  8. #38
    Drew Wiley
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    Re: An imagined LED enlarger light source for 4x5 -- NEW INFO FOR TECHNICIANS

    Everyone knows that LED's can be bright. It's not just the quantity of light that counts, but the specific spectral quality and how to control it. And in this case, you're confusing near-miss architectural lighting for a trio of things that each needs to be way more specific. If it was so damn easy, it wouldn't be an "imagine" DIY thread. It would be wonderful to see a cool compact true colorhead. I won't go into the history of these things, but every time a workaround to the traditional subtractive halogen colorhead has been tried, somebody invested a lot of money without fully appreciating certain inevitable complications. I applaud anyone trying to make their own. I love challenging shop projects myself, and actually operate complex additive colorheads. About all I can say is what I already just have. The spectral parameters of designing something nominally blue and green that works for VC is nowhere near the challenge of a precise narrow-band RGB system truly suitable for color printing.
    Compare that to the fact that a commercial color enlarger made back when Regan was president might be working perfectly still today with a basic tune-up every few decades, and an occasional bulb replacement. I have one of those too, a Durst 10x10 rig.
    But replacements for adolescent technology like LED might go obsolete rather rapidly, just like digital hardware and software, just because things are progressing so fast. Another thing to think about. But it's inevitably going to happen; LED is the future.

  9. #39

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    Re: An imagined LED enlarger light source for 4x5 -- NEW INFO FOR TECHNICIANS

    Everyone knows that LED's can be bright. It's not just the quantity of light that counts, but the specific spectral quality and how to control it.
    Which is why I specifically mentioned that they're available in high CRI versions. And the particular LED I mentioned, while bright, is nowhere near the only one out there. 95+ CRI LED's exist.

    The OP was suggesting a conglomeration of strip LED lights to achieve the equivalent of a bright light source. I was suggesting that a few well-chosen high output, high CRI LED's might be a better solution (for a full spectrum "white" light). Strip lights, while useful for area illumination, are not what you want for a highly concentrated light source.

    If you're looking to go full narrow-band RGB, my next statement may seem ludicrous, but there's been significant progress in mixed RGB lighting for... saltwater reef tanks. Sounds crazy, but there's a similar need for specific frequencies for corals, and to make them look their best. Granted, I doubt an enlarger needs "moonlight" or "thunderstorm" mode, but I would imagine there's some overlap in the concepts behind the technologies.

  10. #40

    Re: An imagined LED enlarger light source for 4x5 -- NEW INFO FOR TECHNICIANS

    Quote Originally Posted by Drew Wiley View Post
    You want to what??? Build a buggy resembling one before roads were paved or shock absorbers invented? Subtractive CMY colorheads are routine because practical RGB additive heads are far more difficult to engineer and realistically require much more light due to much denser sharp-cutting filters. The old Phillips concept was a toy. I know darn well what's involved designing and operating an additive head with some real punch and color purity to it. I've built two of them, and it wasn't a simple task. And at this stage of history, doing so with LED arrays would be like trying to put out a forest fire with a squirt gun. It might work for small prints, so-so hue accuracy, and just having some fun, but seems premature for anything serious.
    The Heiland is an RGB color head in addition to VC coldlight. I have the controller but haven't printed color with it yet. I am thinking that if Heiland stands by it, it will work well.

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