How I built myself Affordable UV LED Exposure Box

This week I built myself an affordable UV Exposure box using LEDs and a plastic box that cost me less than 60eur. During short winter days there is not much sun here in Slovenia so it’s really hard to work with techniques like cyanotype, salt, albumen, lith & carbon printing… This is why I have decided to build myself a 40x60cm UV LED exposure box. It’s not just useful for us photographers that love alternative techniques but can also be used for screen printing, PCB making, Whitening and so on… I designed it in a way that it has two power levels so it can be adjusted if needed so yeah let’s go through the process.

Selecting the lights (LED vs Fluorescent)?

Before I started I had to figure out what kind of lights I should get as they are essential piece of the UV box. There is not a lot but still a variety of options out there among which I could choose. Not just any UV light is good for printing. The ideal wavelength is somewhere between 360-410nm. At the end I was deciding between fluorescent bulbs that peak between 365-370nm or LEDs that peak between 395-405nm. The shorter the wavelength the better so I should buy the Fluorescent bulbs right? Well maybe if I had the budget because they cost almost three times as much for the same size of the box as LEDs. They also take some time to reach full power and when they do they produce a lot of heat as well. So yeah I started searching for the LEDs that are much cheaper, produce less heat and are also much smaller. At the end I ordered 2 x 5m strips of following LEDs: SMD 5050 UV LED 5m Strip

Best box?

Lights came in around a week or so and in the meantime I was thinking a lot of how to design the enclosure. Wooden box was first on my mind which can soon get very heavy and inconvenient to store + you need to have some woodworking skills. I could easily build one but I went on exploring and through reading forums I got an Idea of installing the LEDs in a simple readymade plastic storage box. I already had a particular box in mind which is a bit more industrial with thicker and more durable plastic. During the summer I was converting a minivan to camper and they came in handy 😀 I went to the hardware store and bought one along with some switches. External size of the box is 40x60cm and internal size 36x56cm. Unfortunately I do not have a link to it but I am sure you will be able to find something similar.

Time to start building!

I got the strips in mail and the box was ready to go. Just because it’s easier to work I have also decided to spend a few more euros for a thin sheet of plywood on which I mounted the LEDs. I could have just attached them directly to the inside of the box but soldering and wiring would be much harder to perform. Plywood is not the best surface for adhering so I decided to cover the front with some reflective aluminium tape which will also help with bouncing back all the light that otherwise might be lost. 

Next step was cutting two 5m long LED trips into 20 50cm long ones that will be stacked in rows. I thought I would just be able to cut them with scissors but it turns out that they are soldered together at every 50cm so there I was desoldering each strip. It’s a long process but I don’t mind as long as my hands are working. Once the strips were cut I marked their exact positions on the shiny support so the exposure later on will be as even as possible. Then I started adhering the strips piece by piece leaving a 0,6cm gap between them until I got a beautiful LED screen. It would be great If I could just plug it in and enjoy printing but there was a lot of soldering to be done beforehand. 

I don’t solder often but I definitely learned already that preparation is key. You need to get the wires ready by cutting, stripping and applying solder to them. Solder also has to be applied to the connections on the LED strips so they will bond with wires seamlessly. This is exactly what I did in the next step.