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  1. #1
    galyons's Avatar
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    Converted 8x10 dichroic to LED's!

    Well after about 2 months of toasting $3 Luxeon III LED’s like they were popcorn, I have successfully completed the conversion of a Durst 184/301 head to LED light source.

    Firstly, a big “Thank You” to Huw, whose site and emails helped me to get started. His DeVere 504 conversion was my inspiration. I modified Huw’s layout to accommodate my 10”x10” Durst head and used Luxeon III’s, rather than Luxeon I’s.

    My printing process is pretty much some graded and mostly VC. For VC, I use the split grade technique utilizing a RG Designs StopClock. So my design elements were SoftMax and HardMax as simply as possible. What a joy, no more “spinning the dials” on my color head. Just flip 1 toggle for Soft, green, 1 toggle for Hard & Graded, (blue), both for focusing.

    My previous 8x10 working head, a 1000 watt quartz halogen dichroic, worked very well. Quartz halogen lamps produce most of their light in the red range combined with copious amounts of heat. I was looking for a simpler interface, less heat and less noise, (fans), So the comparison, easy, minimal heat and perhaps, no fan needed.

    What about illumination efficiency? The LED head is 2 ¾ stops FASTER! That makes the LED’s illumination equivalent to my old head with 2750 watts. Think about it. It would take 11 quartz halogen lamps and 2 ¾ time the heat to generate the same hard/soft printing power!

    The Durst head was really a joy as a base platform for the conversion. Lot’s of room in the fan compartment for the 24 volt power source and wiring harness runs. I left the internal fan in place, just in case I need to dissipate some heat faster than my heat sinks alone will accomplish. It has 10x10 and 5x7 mixing boxes that slide in like big drawers. Take the mixing box out and the led panel is readily accessible.

    I am still sorting things out, but the initial testing and process run was very, VERY encouraging.

    I will post more as I get more experience with the new LED head, but so far, I’m sold.

    Cheers,
    Geary
    But your flag decal won't get you into Heaven any more. They're already overcrowded from your dirty little war.
    Now Jesus don't like killin' no matter what the reason's for, and your flag decal won't get you into Heaven any more. – John Prine

  2. #2
    jeroldharter's Avatar
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    That's great. Please post some pics and more technical details. I wish someone here who knew electronics could make a simple 4x5 LED head with green and blue channels like you mentioned for VC printing that would be adaptable to common enlargers (like my Beseler) for a reasonable cost.
    Jerold Harter MD

  3. #3
    df cardwell's Avatar
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    YES

  4. #4
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    Quote Originally Posted by jeroldharter View Post
    That's great. Please post some pics and more technical details. I wish someone here who knew electronics could make a simple 4x5 LED head with green and blue channels like you mentioned for VC printing that would be adaptable to common enlargers (like my Beseler) for a reasonable cost.
    Jerold,
    Just curious, what would you pay? It is doable for a board kit with power supply to be somewhat universal to the major players, Beseler, Omega, Durst & Devere.

    My cost of materials was around $250, (board, heatsinks, LED's, wiring, resistors, connectors, power supply, switches and boxes.) Not really much of a price differential for 4x5 versus 8x10, but perhaps $30-50 less if one uses Luxeon I or fewer Luxeon III's. If one wanted to go with the ability to vary the LED intensity, that would add another $50-75 cost for the PWM board and pots. So for simple split grade printing, the standard retail distribution that would yield a retail price of $1000-1250. Variable add another $250.

    Unfortunately there is not likely the volume to get out of short run pricing. As an example the Luxeon III's come in small quantity cuts costing, today, nearly $4.82 each or in tape reels of 250 for $3.17

    The board can be pre-made in China, Taiwan or India. For a bit more, south of me in the Silicon Valley at job shops. Power supplies from China. But, again the volume levels will probably not drive the price down significantly from what I paid.

    I would appreciate anyone's thoughts on this. The commercial market has not jumped on this, Philips, (Luxeon) was not all that thrilled at my application for the LED's. But...

    Cheers,
    Geary
    But your flag decal won't get you into Heaven any more. They're already overcrowded from your dirty little war.
    Now Jesus don't like killin' no matter what the reason's for, and your flag decal won't get you into Heaven any more. – John Prine

  5. #5
    jeroldharter's Avatar
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    I was hoping for about $500 for a basic blue/green 4x5 light source anticipating a very basic but functional unit with minimal gadgetry. That sounds unrealistic. I think that APUG would be a good market, especially with a thorough review and pics. I am sure I could be persuaded to pay more for good aesthetics and a good review.

    Based on your remarks about cost of materials, I think a universal 8x10 light source with some sort of adapter to scale down to 4x5 would be best for most people and might allow for more economy of scale.
    Jerold Harter MD

  6. #6
    galyons's Avatar
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    Quote Originally Posted by jeroldharter View Post
    I was hoping for about $500 for a basic blue/green 4x5 light source anticipating a very basic but functional unit with minimal gadgetry. That sounds unrealistic. I think that APUG would be a good market, especially with a thorough review and pics. I am sure I could be persuaded to pay more for good aesthetics and a good review.

    Based on your remarks about cost of materials, I think a universal 8x10 light source with some sort of adapter to scale down to 4x5 would be best for most people and might allow for more economy of scale.
    Yes, there lies the conundrum. $500 is probably a marketable price, but the margins would be prohibitively thin for traditional resales from manufacturer to wholesaler to retailer. Even selling directly, one must allow costs for development, testing, multi vendor procurement, kit assembly, handling orders, cashiering,packaging, shipping and customer service.

    Scaling down a unit developed for 8x10 maybe a bit problematic, but derating the LED's from Luxeon III's to I's would work. Their physical footprint is the same. Getting a good board that could be thermally attached to a heat sink board would be the critical step and the greatest need for volume to reduce the cost. I handwired my board, the LED's attached with high thermally conductive adhesive to an 0.1625" thick aluminum board with the finned heatsinks attached with the same high thermally conductive adhesive. A good daughterboard with traces would have greatly simplified the assembly and cut my LED losses.

    I agree that APUG and LFF would be the logical target markets. I would be interested in other thoughts, interest and/or perspectives. More to follow....

    Regards,
    Geary
    Attached Thumbnails Attached Thumbnails Head Wire Runs web.jpg   Power supply web.jpg   CS301 with Dichroic.jpg   Switch 2 web.jpg   Switch Box web.jpg  

    LED Head Ready web.jpg  
    But your flag decal won't get you into Heaven any more. They're already overcrowded from your dirty little war.
    Now Jesus don't like killin' no matter what the reason's for, and your flag decal won't get you into Heaven any more. – John Prine

  7. #7

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    Quote Originally Posted by galyons View Post
    The commercial market has not jumped on this,
    One of the German companies is a making a LED head. But the 8x10 cost is a lot more then $1K IIRC.

  8. #8
    galyons's Avatar
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    Quote Originally Posted by Nick Zentena View Post
    One of the German companies is a making a LED head. But the 8x10 cost is a lot more then $1K IIRC.
    Nick, Heiland is making a split grade head. Yes, the price is much higher than $1000, even in 4x5. I had not heard that they had an 8x10, only up to 5x7. The Heiland system is very sophisticated offering substantial presets and manipulation of contrast. They do offer kits for the Durst CLS301 Head!

    My definition of split grade print is far simpler: "varying the exposure time at max hard and max soft to yield the overall and local, (burn/dodge), contrast you desire". The only measuring/calibration test is with your eyes!
    Cheers,
    Geary
    But your flag decal won't get you into Heaven any more. They're already overcrowded from your dirty little war.
    Now Jesus don't like killin' no matter what the reason's for, and your flag decal won't get you into Heaven any more. – John Prine

  9. #9
    galyons's Avatar
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    The Durst CLS 301 was a great head to convert. There is ample room. The head is well constructed. Each panel can be removed easily for access. The mixing boxes are heavy drawers lined with highly reflective aluminum so the light distribution is very even.

    Also there was no guilt. The CLS 301 really sucked as a 10x10 head since it was designed for the 5x7 138 chassis and fitted, as an economy head for 10x10, to the 184. It only cranked out a whopping 600 watts of quartz halogen light. So it was well under powered for 8x10.

    The basic lighting design is 3 arrays of 6 green Luxeon III LED's, (18) and 2 arrays of 6 royal blue Luxeon III LED's, (12). The power supply is a dual channel 24 volt regulated DC. Each array, per electrical specifications, was terminated to ground with a 1 ohm resister. The array calculated to 1 watt dissipation, but I used 5 watt power resisters. It is cheap insurance.

    So each array looked like this:

    24VDC => +O-+O-+O-+O-+O-+O- 1 ohm 5 watt resister.

    I built color coded wiring harnesses and used terminal blocks to facilitate assemble, testing and repair.

    The LED layout was inspired by Huw, but I slightly modified the layout to better accommodate the 10x10 head. I hand-wired my board, the LED's attached with high thermally conductive adhesive to an 0.1625" thick aluminum board with the finned heatsinks attached with the same high thermally conductive adhesive. A good daughterboard with traces would have greatly simplified the assembly and cut my LED losses.

    I built color coded wiring harnesses and used terminal blocks to facilitate assembly, testing and repair.

    The LED’s were laid out on a 10MM grid. Huw calculated this pattern to provide even illumination for his DeVere 504 5x4 conversion using Luxeon I’s. I used the essential layout with the Luxeon III'x to accommodate both 5x7 and 10x10 mixing boxes on the CLS 301.

    More to follow,
    Geary
    Attached Thumbnails Attached Thumbnails Head Wire Runs web.jpg   Power supply web.jpg   LED Head Grid copy.jpg  
    But your flag decal won't get you into Heaven any more. They're already overcrowded from your dirty little war.
    Now Jesus don't like killin' no matter what the reason's for, and your flag decal won't get you into Heaven any more. – John Prine

  10. #10

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    Quote Originally Posted by galyons View Post

    My definition of split grade print is far simpler: "varying the exposure time at max hard and max soft to yield the overall and local, (burn/dodge), contrast you desire". The only measuring/calibration test is with your eyes!
    Cheers,
    Geary
    Ya that would be fine with me to.

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