Converted 8x10 Dichroic to LED!

[Geary Lyons]

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 RH 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

[ic-racer]

This is really fantastic, but can you post pictures and a schematic?

[BarryS]

Sounds great. I'm mostly a split grade printer myself, so the single switch LED source sounds like it would be a good upgrade. I'd *really* appreciate some solid documentation of your project. The commercial market is not really doing much in the way of darkroom technology development, so these homegrown projects are one of the only ways to move the art forward. Definitely check out some of ic-racer's excellent posts for a good example of project documentation.

[Geary Lyons]

This is really fantastic, but can you post pictures and a schematic?

I am working on a more detailed article with pictures & schematics.
Cheers,
Geary

[Jon Shiu]

Wonderful news, Geary! Hope to see some of your prints sometime!

Jon

[Geary Lyons]

Sounds great. I'm mostly a split grade printer myself, so the single switch LED source sounds like it would be a good upgrade. I'd *really* appreciate some solid documentation of your project. The commercial market is not really doing much in the way of darkroom technology development, so these homegrown projects are one of the only ways to move the art forward. Definitely check out some of ic-racer's excellent posts for a good example of project documentation.

Well, I will do my best! I will keep my "report" generic. That way the basic principles could be applied to other heads/enlargers. It will have, perhaps, more practicality than a brand/model specific article.

Regards,
Geary

[rob]

What LED color do you use? I 've been planning to do the same using luxeon royal-blue and green for my 45mx and vivitar VI.

[David A. Goldfarb]

Sounds excellent. I could see a homebrew 8x10" enlarger in my future.

[Geary Lyons]

What LED color do you use? I 've been planning to do the same using luxeon royal-blue and green for my 45mx and vivitar VI.

Rob,

Those are the colors that I used. The green wavelength is right on for Soft contrast. The royal blue is the best available choice. The royal blue is just a slightly longer wave length than the peak Hard contrast sensitivity, but in split grade printing you will not notice.

Cheers,
Geary

[Turner Reich]

I was checking and the Leds you mentioned are listed for $5 and up in price, where can we get them or $3.?