Questions about a DIY UV Lightbox

[hazardsg]

I'm starting to put together a parts list for a UV light box for alternative process printing. Here's a list of the parts I've been looking at.

2x Fulham Workhorse 5 WH5-120-L Ballast (each should handle 4 lamps)
https://www.1000bulbs.com/product/2169/BF-WH5120LC.html

F15T8/BL - 15W T8 Fluorescent Blacklight Bulb
http://www.topbulb.com/f15t8-bl-15w-...0nSRoCsO3w_wcB

16x Leviton 23651 - T8
https://www.1000bulbs.com/product/5310/SOCK-L23651.html

I am currently planning on contact printing 8x10 negatives. I was thinking that would be nice to build a unit that could handle 11x14 so that I have a little room to expand if I decide to either print larger digital negatives or build/buy an 11x14 camera.

Will 8 18" bulbs evenly illuminate an 11x14 area?

I see that the ballasts need to be grounded. I've never messed with fluorescent lights. Do the sockets for the bulbs also have to be grounded? I think I've seen some examples that have the sockets screwed to a thin metal plate.

Do I need to add cooling to the box? If so, do I need to cool the ballasts, the bulbs, or both?

I am thinking about using baltic birch plywood for the actual box. Any idea on what distance the bulbs will need to be away from the contact print frame to achieve even illumination while getting the fastest printing speed?

Am I missing any components for the basic circuit for the lights? The manufacturer has wiring diagrams for the ballast and bulb combination I am planning on using. I will also probably use a regular light switch that lights up when on.

I know some of this might come down to trial and error on my part. I just want to try to avoid any costly mistakes before I start buying materials.

Thank you for any help,

Steven

[Will S]

There is a great article on unbinkingeye by Sandy King that answers most of this: http://unblinkingeye.com/Articles/Light/light.html

Grounding is just screwing the groundwire to the fixture I think (caveat: I'm not an electrican!)
You need cooling.
He lists distances. With bulbs 1/4" apart you can get very close. I seem to remember 3" or so.

Be sure and post your finished unit and parts list here. Would love to see it!

[Henry Yorke]

Steven.

You might look at this thread:

http://www.largeformatphotography.in...ht-Box-(16x20)

Jim Sidinger put together a UV lightbox a couple years ago and posted about it - lots of interesting info on this thread.

[Fr. Mark]

I used 6 bulbs of the kind you got top bulb likewise the tabs that the wires and tubes connect into and 3 ballasts I found at either lowes or home depot (big box hardware/lumber store in US) and I had a wood box in form of a kitchen cabinet drawer that I repurposed for mine. I used a typical household light switch I had around and then for more reproducible results, connected the whole thing to a gra-lab timer. With some negatives I'm finding that 30-60 sec. gives good results for cyano-types (Mike Ware's recipe) gives good results at 8x10 about 4" (100mm) from the bulbs. Bulbs are evenly spaced and I built mine with an eye to making 11x14 or 14x17's someday. Remember the UV will spread out some, so coverage could be larger than the light box though that will make the intensity drop off and exposure time will go up.

Denser negatives (Background+fog) will take longer.

I think that I have about $50-75 in mine: bulbs/tubes were about $4-5 ea, ballasts maybe 10-15 ea., tube/wire holders $1ea (12$ total) Box, wire, 3 prong plug cord, grommet, switch, timer, screws, wire nuts were all from other other projects. If I'd had to buy all that, minus the timer, I doubt it'd've doubled the cost, maybe if you shop carefully for the timer it still wouldn't double the cost.

As to wiring, the ballasts I purchased had wiring diagrams, I just followed them and connected everything with wire nuts in a junction box and that to a switch.

go for it, and enjoy alt printing, its a lot of fun!

[adelorenzo]

I considered making my own unit but ended up getting a unit like this one. It's a six-bulb, 24-inch T5 unit that more than covers my 12x16 contact frame.

http://www.ebay.com/itm/Virtual-Sun-...item2eccf77e2c

I replaced the grow lights with Super Actinic aquarium bulbs, ending up with a total cost around $200 and no need to build or wire anything.

[Natenaaron]

Adelorenzo,

How has that unit been working for you?

[adelorenzo]

I've been using it for salt, cyanotype and kallitypes and it works great. Typically I get 3-4 minute printing times, depending on the negative and such of course. The bulbs I use are are ATI Actinic aquarium bulbs, I have not tried it with regular UVB (blacklight) bulbs.

[Len Middleton]

Another alternate might be to pick up a surplus plate burner, as the print trade has little use for them.

Purchase price for mine was C$75, excluding the cost of getting it home after finding it would not fit into my hatchback.