In my journey through learning alternative photography techniques, I ended up having to create a UV exposure box. My knowledge of circuitry was very limited and effectively non-existant for lighting components. I spent countless hours trying to figure out how to build this thing, and even blew a few ballasts in the process.
I’m documenting my build here to help you through your own DIY project. This won’t the prettiest or professional DIY build, but with the basic components, you can build an exposure box for under $200. Just for reference, I built my box for printing up to 16″x20″ prints. With this build at a height of 4″ above the contact frame, my print time for Platinum Palladium on Revere Platinum paper is roughly 3 minutes and 45 seconds.
Disclaimer: You assume all responsibility if you decide to build a UV exposure box. Electricity, especially AC power, can be deadly. Proceed at your own risk, I take no responsibility for your mistakes or issues. It’s unfortunate that we have to place this kind of disclaimer, but there are too many idiots out there looking to blame other people when they fuck up.
I went through quite a bit of a tuning process in my Platinum Palladium workflow and this image was my first print! It’s an 8×10″ print on 11×15″ Revere Platinum 320gsm paper, using the PtPd Na2 chemical kit from Bostick and Sullivan.
This blueprint uses AC power, which is very dangerous, but was the simplest for me to start with as I didn’t have to worry about buying a power supply to convert from AC to DC. Additionally, there are two independent circuits in this design – 1. for the ballasts and lighting 2. for cooling fans. They are operated by independent switches. Ultimately, I actually did not wire up the fans or switches and use an external power strip to switch the bulbs on/off. I also didn’t need the fans since my print times are so low and my indoor ambient air temperature is usually 65f.
|1||Plywood Board – 24″x24″x1/2″||Any decent plywood board from a hardware store like Home Depot|
|3||Fluorescent Light Ballast||Philips Advance Ambistar REB-4P32-SC|
|12||Ultra Violet Bulbs||18″ Sylvania F25T8 350BL|
|24||Tombstone Sockets (Non Shunted)||T8 Non-shunted, Generic Brand|
|1||Fuse||Generic 5 amp, inline Fuse|
|1||Terminal Bridge||Generic Terminal Bridge|
|1||120 VAC Plug||14 Gauge, 9 foot, Replacement Power Cord|
|1||Aluminum Tape Roll||Nashua Extreme Weatherfoil Tape|
|1||Electrical Wire Pack||Black, White, Red, Yellow, Green|
|1||Assorted Hardware||Screws, Nuts, Bolts for mounting components onto the plywood|
|5||Electrical Wire Connectors||Generic Connectors, Appropriate Gauge|
|2||Single Pole, Single Throw Switch||Optional|
I chose a 24″x24″ as the dimensions for my board since I do not currently plan on printing larger than 16″x20″ prints. That being said, I think my build is powerful enough that I could raise the distance between the contact printer to spread the light out further for larger prints – if I ever go down that route. Obviously, one would have to adjust exposure time.
The lighting ballast is the component which regulates electricity to the bulb, providing the right voltage to ignite the gases and to manage appropriate levels of energy to not overheat and blow out the bulb. You need a ballast that’s capable of managing the number of bulbs you’ll be hooking up including the necessary voltage and amperage. For my build, I decided to go with 3 x Philips Advance Ambistar REB-4P32-SC ballasts which are inexpensive and capable of driving 4 x 25 watt bulbs each. The ballasts are “instant start”, which use less wattage per bulb, and can start in challenging temperatures.
Ultra Violet Bulbs
The bulbs are the most critical component to get right, otherwise you will not have success with your alternative photography projects. There a few different types of UV bulbs, including Black Light (BL), Black Light Blue (BLB), Actinic, Super Actinic, and AQUA. For this build, I chose 12 x 18″ Sylvania F25T8 BL tubes, which stands for – Fluorescent, 25 watt, T8 shape, Black Light tubes. I recommend you do not choose BLB bulbs, as they are filtered novelty bulbs and will not operate within needed UV range (e.g. 350-380nm wave length).
I chose to go with standard tombstone sockets as they are cheap, provide flexibility in spacing on the board, and easy to work with. Make sure to choose tombstones that are of proper size for your bulbs – in my case T8.
I chose to go with a 5amp inline fuse to protect my circuit from blowing in case of surge or over draw in current. In total, my circuit is expected to be 340 watts @ a low amperage. Make sure to put this fuse on the hot wire before any components in the circuit, otherwise it defeats the purpose as power will surge through the components.
I used Nashua aluminum tape to wrap the plywood, particularly on the bulb side – this helps reflect maximum light to the contact frame. It’s a very thick, heavy duty material and may even help reflect heat away from the wood, albiet probably minimal.
After you have obtained the raw materials, plan out your build by measuring and marking up drill hole locations on the plywood board for the ballasts and tombstone locations. I physically laid my assembly onto the board to help me mark up the arrangement before drilling holes.
Otherwise, the wiring is straight forward. I connected my system according to the diagram above, using twist connectors to combine components on the same circuit, and I made sure to solder the inline fuse for a strong and secure connection. Make sure to properly coverup any exposed wiring as that could be a fire hazard.
As you may notice, the blueprint doesn’t illustrate how to elevate the UV light box. Currently I use some feet that I drew up in CAD and 3D printed. They work for my solution, but you may want to look into something more sturdy.
Good luck and please do share your photos or setup if you found this article useful!