LED Exposure unit

[wetgravy]

Right now I have a halogen exposure unit ... very efficient, very hot and very green unfriendly. I'm looking to build a new unit ... but not sure what I want yet. No one on the market has one in LED that I can find ... it's all incandescent, halogen or flourescent. Has anyone tried an LED exposure unit? did they notice any difference to the way the emulsion reacts? Will it react at all? If the lumens are the same ... is it a different reaction rate than say ... flourescent?

 

[James Burke]

I didn't know that LED lamps are capable of putting out enough nanometers of UV wavelength. Is it even possible?

 

[wetgravy]

In my shop we have ultra violet LED's. They just look purple, but that is why I am asking if anyone else has even remotely seen LED's used.

 

[surf city]

Good question, it would be interesting to know if it will work.

 

[wetgravy]

In my search for one, this is the only LED light box I can find ... for DJ'ing none the less.
http://www.chauvetlighting.com/led-shadow.html

So it might be possible ... just might be expensive as chit.

 

[Poconopete]

http://www.instructables.com/id/UV-LED-Exposure-Box/

 

[wetgravy]

hmm, well, if I need to expose a 22x30 screen ... and I space an LED out half an inch each way, that would be an 36x52 grid (assuming an inch gap on each side of the board) which would be 1872 LED's ... My cost for just the diodes would be around $1600 ... I think I will stick to flourescents

 

[mikey-Oh]

i use the sun, it's pretty green friendly.

 

[Poconopete]

i use the sun, it's pretty green friendly.

I tried that last night. It didn't work.

 

[phototec]

The best way to use LED's in an LED exposure unit

Probably the best way to use LED's in an LED exposure unit, would be to make it like a giant scanner. Have two geared tracks on the side and make a exposure bar with LED's all the way across (22" long), and the exposure bar would move across the length (30") exposing the screen, you could have a control to adjust the speed of travel, which effectively would vary the exposure time.

The exposure bar could have the LED's spaced about 1/4" apart, which would only require 88 LED's ($75). And at that spacing, the exposure bar would be very bright, and allow the exposure bar to move at a acceptable speed.

 

[epatsellis]

Is there any reason why you don't use a NuArc with an integrator, they sell pretty inexpensively, mine cost me nothing, in fact. (though I use mine for photographic pursuits, not burning screens, though I have in the past)

 

[wetgravy]

nuarcs are fine, I just wanted to make something a little more custom though. LED was just a thought, trying to get rid of my old halogen unit though, heat kills me.

Yeah, I think I am going to make a light table that has alternating florescent lights that will be white, uv, white, uv, white ... and throw the uv and white bars on seperate switches. Also going to have 2 pieces of removable acrylic for it, one frosted and one not. That way I can also upgrade my lightbox (little overdue for that) and have an exposure unit too while not killing all the room in my studio.