Simple Led Head for DIY 8x10 Enlarger.

[frederic.legac]

Hi All,

Probably this topic has already been covered, but I didn't found exactly what I need to start my project.

I want to build a 8x10 Enlarger. I have a old (with new bellows) 8x10 Camera and I would like to use it as a horizontal enlarger.
I just need the simplest as possible. No color head, just light, film holder and lens.

Regarding the head, I'm considering to use Pure White Led Panel (12"x12"). Is it a good idea ?

If you already made this kind of work, let me know...

cheers,

Fred

[Lachlan 717]

Did you see this thread? (http://www.largeformatphotography.info/forum/showthread.php?106071-Customized-8x10-Codelite-LED-Head-for-Variable-Contrast)

Might not cover exactly what you're after, but there could be some good (additional) information within it...

[frederic.legac]

Thanks, I'll check this.

Fred

[Drew Wiley]

You'll obviously need some diffusion. Ordinary sign white acrylic sheet should work fine. What the actual spectral makeup of your "white" light will be is hard to say
unless you have spectrograms of the actual bulbs. Just for fun I have someone sending me in white industrial LED panels for testing, which I'll view thru deep blue and green tricolor filter just to see whether something on the cheap would actually work well for VC papers. The odds of anything like this working well for actual
color printing are rather small, however. I'm skeptical that LED lighting is anywhere near that point yet.

[Neal Chaves]

I have been looking at LED technology, but I still find that my Aristo daylight tube with yellow and magenta gels to adjust contrast is the most cost-effective solution. My first 8X10 enlarger was an 8X10 camera on which I made many nice (I think) prints. It was, a B&J Grover monorail I used vertically on a Bogen Expan Pole. The light source was a double circuline daylight fluorescent light fixture with a round flat diffuser you can buy for about $50 in a home improvement store. The diffuser was all masked off with black tape except for an 8X10 opening on the bottom. I put a plain ground glass in the camera. The light source attached to the focus panel with Velcro and I used a hinged glass negative carrier the size of a film holder that I inserted the same way. I adjusted contrast with Ilford 4X4 VC filters on top of the lens rear element.

These light fixtures flicker when they come on, but always the same way. I make my test strips with the light on constantly, even with filament bulbs. Using a timer with an audible metronome set for thirty seconds, I expose the first increment for 4 beeps, then move the card every three beeps making a ten increment thirty second test strip. If I make a 60 second test, I expose the first increment for seven beeps and then move the card every six beeps. This is the most accurate way to make a test strip with any light source and will save you much time and paper.