LED UV Light Box: Build Your Own for Under $150

[macandal]

To follow up on this ... I am still convinced that a person interested in building their own UV light box would be better served at this point in time by BL or BL tubes.

So, if I'm understanding it all correctly, it is better to buy one of these:

BLB

Over one of these:

BL ???

Or even over a regular T8 UV light?

Thanks for all your help.

[stawastawa]

and if anyone has a source for ballasts and sockets I need a recommendation (for 15 W T8 BLB bulbs).

[williaty]

This is my parts list for assembling a UV source:

Ballasts Fulham WH5-120-L QTY 3 from 1000bulbs
F25T8 17"-nominal BL tubes Sylvania part number 21703 QTY 13 from 1000bulbs F25T8/350BL/18in/ECO
Lampholders Leviton 23351 QTY 26 from 1000bulbs
SOOJ 14-gauge cable 6 feet from HomeDepot
NEMA 5-15P plug end Leviton 5266-C Amazon
120mm Case Fan AC Infinity HS1238A QTY 2 Amazon
Switch Leviton 5611-2WS 7.64 1 7.64 Amazon



That list is a mess, sorry. It didn't paste out of spreadsheet at all well.

[sanking]

So, if I'm understanding it all correctly, it is better to buy one of these:

BLB

Over one of these:

BL ???

Or even over a regular T8 UV light?

Thanks for all your help.

BL and BLB are both UV tubes, with peak energy at about 365 nm. The only difference is that the BLB has a Woods filter that blocks light above about 420 nm. I have used them both in alternative printing and they print with about the same speed.

UV tubes could be T12 or T8, this has to do with the diameter of the tubes. T8 tubes are more efficient and the T12s are being phased out.

Probably won't be long before we see the BL and BLB T8 LED tubes, perhaps as drop-in replacements for the T8 fluorescent tubes.


Sandy

[BetterSense]

if tubes give exposure times on the order of 1second, I anticipate a repeatability problem. Although I am a huge fan of tubes, I don't use short exposure times, and I expect LEDs probably turn on and I ff more predictably. To those using tubes: do you use a standard enlarger timer?

[williaty]

I don't use short exposure times with tubes either. Less than 30 seconds to a minute or so and I'd be spacing the light source farther away from the print to get longer (more controllable) printing times.

[sanking]

if tubes give exposure times on the order of 1second, I anticipate a repeatability problem. Although I am a huge fan of tubes, I don't use short exposure times, and I expect LEDs probably turn on and I ff more predictably. To those using tubes: do you use a standard enlarger timer?

Exposure time with all types of lights with UV sensitive alternative processes is on the order of minutes, not seconds, and in that range tubes give consistent results with standard enlarger timers.

HID lamps, such as those found in platemaker units like the NuArc 261k and Amergraph ULF, take a long time to reach full radiation, and require more precise timing which is done with light integrators which measure the actual amount of radiation and timing is done in units, not seconds or minutes.

Sandy

[denverjims]

and if anyone has a source for ballasts and sockets I need a recommendation (for 15 W T8 BLB bulbs).

I used 1000Bulbs.com for the tombstones (sockets). Search site for 'Levton 23351'. Note that this shunted type is for use with 'instant start' type electronic ballasts like the Fulham Work Horse WH5-120-L I used in my build. A different type ballast (like programmed start [& I think rapid start]) need a non-shunted 13351.

I found the bulbs in Home Depot but they are also available at 1000Bulbs.com - $4.56 last time I looked; but you pay shipping.

My complete project notes are on the forum here: http://www.largeformatphotography.in...53#post1069353

By the way, one issue with using fluorescent bulbs and ballasts (as opposed to LEDs) in an enclosed space like this is the heat buildup. That is why most who build use a fan in their design. I found that it was useful to use a 2nd switch for the fan only; separate from the one for the lights. This way I could continue to cool the compartment after turning off the lights. Made for less time between exposures without as much heat buildup.
Best, Jim

[macandal]

So, I have a few more questions before I start planning my own UV exposure box. As I said earlier, I am not very good at building things, so if my questions seem dumb is because I am completely out of my element here.

1. I don’t want this box to be tall (?). I’ve seen some boxes that, looking at them from the front, are simply too tall, a couple of feet tall. I am trying to keep mine only a few inches tall. The Arista boxes are, I believe, 7 inches tall. Sullivan & Weese’s box is 8 inches tall. How much space should the ballasts have? I mean how much space should there be from the top of the ballast to the “ceiling” of the box?
2. How much space should there be from the lights to the bed where the negative/paper will rest?
3. How does one determine how many lights should there be in a given area? Take the example offered by Sullivan & Weese in The New Platinum Print (pg. 86). Their exposure area is 18”x20”, and they installed 12 eighteen inch candles. How did they determine that twelve would be enough lights? Or is twelve just a random number? If properly spaced, could I pick to do a box like theirs with only 6 candles?
4. How does one settle on the wattage for the candles?
5. Is the fan absolutely necessary? Some people here have said that they built boxes without fans.

If I think of any other questions, I’ll ask later, for now, this is it.

Thank you.

[jp]

3. If you do too few, you will have uneven illumination. if you do too many you will get shorter print times, so I erred on the side of too many. It does not get hot.

You can see here how mine is done.. It's about 11.5" tall and uses the 18" bulbs . https://www.flickr.com/photos/137596...th/9480354531/

If you are not just being humble and are indeed bad at building stuff, you may want to enlist the help of an experienced friend or two for construction and especially wiring.