DIY UV exposure box

[Brian Ellis]

I built a light box that wasn't nearly as nice as this one but easier to build and did the job. It was basically just a rectangular plywood box with no bottom and was open on the two long sides, plywood on the two ends, about 8-10 inches high. I attached the light fixtures underneath the top, the lack of sides allowed enough ventilation without the need for fans, and I had a lot fewer lights than this one - three fixtures, six lights I think (it's a little surprising how well the fixtures spread the light evenly despite being pretty close to the printing frame). I didn't find a need for reflective lining though that's a nice touch.

The lights were bought at a local light specialty store, the fixtures and plywood at Home Depot. Since the two long sides were open I could just slide the printing frame in and out without needing hinges. Total cost was probably about $100 or less, took an afternoon to build (with help from someone who knew more about electrical fixtures than I did) and worked well for the Van Dyke brown gum printing that I used it for.

If I was a more talented woodworker/electrician I would like to have had something as nice as the OP's but the one I had did the job and sure made printing times more predictable than using natural light.

[Drew Bedo]

I have always thought that a UV disinfectant box from a barber shop/salon might fill the bill if it could be had at a savlage price.

[Dan Dozer]

That looks just like mine aslo, except that I left the bottom off and just sit it on my darkroom counter. I have two boxes, one for 8 x 10 and one for 8 x 20. Your cost checks out at about the same as what I paid for also.

One other thing - I didn't put the reflective insullation inside of my boxes. Do you think that you get shorter exposure times with it? My normal exposure times are between about 3 - 5 minutes.

[jp]

I basically wanted stray light reflected (some might end up on the photo) instead of absorbed (none will end up on the photo). For example, given equal light sources, a darkly painted room will be darker than a brightly white painted room.

Two easy ways to do that. Traditionally one would paint it white to reflect light. Fluorescent fixtures use white painted metal reflectors to do this. Rather than stir paint and change my clothes and wash a brush after and all that, I went the easy route and used reflective metal insulation. It goes on fast and reflects heat as well as light. I can't quantify how this would be different than white paint; it reflects well and goes on quick and neat.

Also, the 15x11 watts of energy of the light bulbs has to go somewhere, probably very little will go to chemical change of the paper and most will be heat. I wanted to be sure excess heat didn't rise into the wiring compartment, and reflective insulation does prevent that very well. Sort of a belt-and-suspenders approach in case the cooling fan failed, it wouldn't turn the wiring compartment into an easy-bake oven.

I have a base on it unlike some boxes as it will be used on a shelf under the sink rather than tabletop. My darkroom lacks counter space. I have a 6' sink the length of one side, and on the other side I have two enlarger's baseboards for horizontal space.

[jp]

Not bragging or anything, but this is working out REAL handy that it's deep enough to hold 2 8x10 frames. I can be twice as productive on small prints.



If anyone is building one, definitely size it to fit two small frames if you do much small printing.

[NancyP]

Remember that UV is bad for your lenses - the proteinaceous ones inside your eyeballs. Yes, we all get some UV exposure in daily life - that's why we develop cataracts late in life. Don't stare at the bulb without using UV-blocking glasses. This advice is given by an M.D. and researcher who has looked at a lot of ethidium-bromide-stained nucleic acid gels on 302 nm UV light boxes - for very short glances - that's what the old polaroid 66 snapshots were for, permanent documentation and for measurement of bands on the photo, not on the gel itself.

[denverjims]

I agree about the danger of UV to the eyes. Having built a unit similar to jp498's myself (see my post elsewhere in the DIY subforum) and having worked in a lab where UV was used, I decided to get a pair of UV protective goggles. Found a pair on Amazon for only $22 (UVP 98-0002-02 Model UVC-503 Plastic UV Blocking Goggles Eyewear for Shortwave UV Light Protection) and felt it was a good investment. They are very comfortable and I don't have to worry about UV damage. Note: similar ones may be available elsewhere for less.

[jp]

My box's hinge stops light from emanating from it. I have it on a timer, so it's off when loading and unloading it. It's a lot of light in a small space and would be hard on the eyes regardless of how visible it is.

[Fr. Mark]

Anyone built one of these a lot smaller? Like maybe 4 tubes and designed to cover 8x10 only. I don't have a lot of space or money but want to take the cyanotypes to the next level with digital negs or X-ray film (likely both).

[grzybu]

I've bought small, used face tanning unit from Phillips for about $20. It covers more than 8x10 and exposure times are from 2min for Kallitype to 8min for carbon printing using my glop. I just had to glue piece of wood at the front of the cover to keep constant distance from contact frame.
In winter times sometimes I sit in front of it while exposing with my eyes closed and I gather some vitamin D