Home made RGB proportional led head for my Durst 138/139 5x7 enlarger
This project is presented in detail in the APUG "The smoking solder iron - DIY" group but as it might be of some interest for the whole APUG DIY community, I will also introduce it here in the general forum.
Please note this a RGB LED head for B&W printing only.
The main characteristics of this LED head are:
* 3x independent colour channels (R,G,B). The Red channel is 12W only and it is mainly used as a safe light.
* Each channel is current controlled. The amount of light can be adjusted in real-time thanks to a PC software and a remote control
* The transfer function of each channel has been linearized
* In its current configuration, the maximum power consumption is ~85W (equivalent to a ~500W light bulb at least). I could extend it to the limit of my driver (120W). This would require me to invest in a new and big power supply. As my darkroom is quite full, I rather prefer to avoid this option for the moment. The head can be run at 150W with a more powerful driver (~ 900W light bulb) but this, I'm sure, won't be necessary.
* Cold design (the LEDs are mounted on a big heat sink)
Full story here.
I believe that LEDs are the wave of the future. Especially as proper bulbs to fit various enlargers become harder to source. That's a ways away, but it may be coming.
I would like to see something like this become commercially viable, but the light sources would ideally be reasonably priced, and usable with existing conventional timers.
Anyway, your creation looks promising. Keep up the good work.
David: Thank you for your kind comment!
Chris: Their light heads looks very well made indeed! Their model 3 and my head look similar and they share the same concept (colored LEDs channel controlled separately) but it is sized for 4x5 printing
My thoughts exactly! I'm probably going to invest in the model 3 for my D2VXL to facilitate hands free split-grade 30x40" prints...
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