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Discussion in 'Enlarging' started by Mr Worry, Jan 22, 2009.
Has anyone used an LED light in their enlarger in place of a regular bulb & got good results ?
I haven't really tried it, but have some AC LED arrays that might work and an idea for some LED bars inside a D5XL condenser box. I can think of two possible problems, and some possible advantages. First is the spectrum. You might want warm white LEDs for using with VC papers, as that might be a better match to standard VC filters than the cool white LEDs, although the cool white ones might cover that end of the spectrum just fine. The other is that I've though about a mixed array of blue and green LEDs on separate potentiometers for VC control. This has been done already, and some commercial offerings may be out there. Google "Huw LED enlarger" and it might come up.
The other problem is that the LEDs in an array would tend to show up as a pattern on a condenser enlarger. Diffusion would most likely be necessary.
Others have successfully done this, and I intend to, also. Do a search on APUG, especially for the 8x10 conversion and the LED head
Check the Calumet site. They were producing one (or said they were going to) for the Zone VI enlarger. Alan Ross wrote a review of their LED head a while back. Either in View Camera or Photo Techniques. It was/is quite expensive, $1200 as I remember.
Dear Mr. Worry,
Look here: http://www.huws.org.uk/
The people at candlepowerforums.com would probably be eager to help. They are insane about all kinds of lighting. I guess there are some recent LEDS that have very good output spectrum for color rendition, and they get better all the time. I would look into that flavor of LED because most white LEDS have a strong blue peak, which could, I guess, cause a problem with variable contrast paper, and it would certainly throw off all color filters.
The white LEDs of which I'm aware use a UV emitting diode to excite a phosphor coating similar to fluorescent tube phosphors. This can be tuned up for certain color biases, but there's often a strong UV component in white LEDs. Then again, I could be behind the times on LED developments. Many sites with technical info show the LEDs emission spectrum.
I replaced my cold lamp head with LED's a year or so ago, using as unscientific a method as merely adding LED's 'till it was as bright as the original head (so I could use all my old exposure notes). I'm very happy with it and the contrast if anything seems the same as the head it replaced, but without the "warming to colour temperature" issues, and of course vastly less power used, and runs cool - which is lovely because in keeping the old head on most of the time for consistancy, it would tend to buckle roll film...
There's a picture of it in one of the posts mentioned above.
Hey thanks for all the helpful comments
you can check out Heiland Electronic in Germany
He is offering a LED head
Try this site:
He uses LED strips that can be plugged together, and just require a simple 12 volt power block.