How to make a UV LED Exposure box / by greg brophy

Up close on the UV LED exposure box


I made this box about a year ago and after 1 years use, I am not sure I would still recommend doing this. I went to add some more lights to the unit this week and noticed that the lights, which have a plastic waterproof coating over them had yellowed and that the new lights which were the same as the original were much brighter. I read the reviews of the LEDS on Amazon and a lot of people complained about the same thing. They only thing I can think of is to use LEDS without the waterproof cover and that are of better quality.

I have a Nuarc 40-1K and an fluorescent exposure box I made and decided that I needed something quieter, cooler and less power hungry so I made a UV LED exposure box. I put this information together from these two links:

Before we start, I am not an electrician and you do this at your own risk.

The video is an excellent source for some of what you need and how to wire it. The process I did required soldering. I learned how to solder a long time ago and it’s really not hard. You may be able to do it without soldering but I do not trust the long-term ability of the clips to keep the connection. I created a really large UV light box at about 30x36 inches but it’s easier if you do something like 20x24. I made mine that large to fit over the vacuum frame I have.

The UX exposure box I made gives me a maximum black at about 12 minutes with Fixxons transparency material that I use for my digital negatives. Right now, the height is about 4 inches from the negative. This may change but it doesn’t really matter much if it is 4 or 6 inches. The LED strips are 3/8ths of an inch wide and I centered them on an inch strip (30 inches for 30 strips). The video shows the lights really stacked on top of each other, but so far I have gotten pretty even light with some space in-between. I also staggered where they begin and end so that the coverage is more even and not just strips of LEDS horizontally. The video does a good job of explaining this. You do not need the battery or the extra stuff he shows in the video, just the power transformer.

Results from a 10 minute exposure using the UV LED exposure box. It could use a couple more minutes. 

When you cut the LED strips, make sure it is between the two copper points (about every three LEDs). Make sure all the strips go in the same direction. How can you tell? Well when you line them up, you will see at the ends of the LED strips, two copper dots, one negative and one positive. The ends should match, so for instance all the negative copper terminals should be on the top and the entire positive terminal on the bottom. This way it makes it easy to line up and solder. You are going to take the 12 AWG wire (basically speaker wire) and have it go through holes you have to make in the center of the short sides. The speaker wire is a paired wire, one wire to go to the top and one to go towards the bottom. It doesn’t matter which is which. Start on one side and strip the red and black off so that it reaches just past the leds. Give it about an inch from the top of the LEDS. Staple this down and start soldering the small copper wire to each one. For the one side you want the negatives and the other side the positives. You do not do all of them on both sides.

Once you are done, test with the power supply. You should have three positive and three negative connections on the power supply.  The one 12 AWG cord (with the red and black cord inside) from the right should go into the positive connections on the power supply and the one cord from the left should go into the two negative terminals. Which side doesn’t matter as much as long as the wires soldered to the negative side of the LED terminal is plugged into the negative connection on the power supply; same with the positive. Then connect the power cable, black is live, white is neutral and green is ground. Plug it in and step back. The lights take about 2 seconds to turn on. Once it is all working, flip the board over and attach the power supply to the board and you are done.

I have saved everything I have used into a wish list from Amazon or you can check out the links individually below.


I will keep updating this with more images and better directions as this process evolves. 

Here is a schematic I made: 

UV LED Exposure Box Schematic from underneath. Click to view larger size.

Power supply – can power 5 reels of lights at a time (Shipping says it will take a month but I got it in two days)

UPDATE: I would also strongly suggest getting a plastic ABS box and drill some holes in it for ventilation.

Connect led strips together

OOK 50162 20 Gauge, 50ft Copper Hobby Wire

Check update at top: Wit-Lighting 16.4ft 5050 LED Strip UV Purple 395nm-405nm 5M 300 SMD Flex Light Waterproof IP65 12V DC DC 12V 5A for 5M 300LED light strip Viewing Angle : 120° Wavelength:395-405nm Long life span 50,000+ hours (Shipping says it will take a month but I got it in two days) This is what I used, but would not recommend, they turn yellow and lose brightness in a year.

500w DC12v Output Switching Power Supply Adapter Non-waterproof LED Driver transformer for LED Strip Light (for reels of 6 or more)

Power Cord
Cmple 12 AWG CL2 Rated 2-Conductor Loud Speaker Cable for In Wall Installation (White, 100')

12AWG Copper Speaker Wire