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

[Cor]

First, how do you know your exposures will be short? With certain processes and types of negatives exposure times can be very, very long.

Sandy

This weekend I printed a 8*10 HP5+ negative, first developed in Xtol, the neg had already considerable B+F, made a few silver gelatin prints. Since I thought the neg could also "work" as a Pt print I bleached it and re-developed in Pyrocat. Picked up quite some stain.

Printing on my home made UV box (6 closely spaced tubes, printing frame close to the tubes)..it took 2 hours for a decent print..

Yes this is extreme, due to the combination of high B+F, strong pyro stain, and pure platinum printing which in my hands is the slowest process..the 2 fans I build in are no luxury..

Good luck,

Cor

[macandal]

...made a light box with BLB CFLs. They have ballast built in...

Where did you get these? Can you post a link?

Thank you.

[j.e.simmons]

Where did you get these? Can you post a link?

Thank you.

I lived in Jacksonville, Florida at the time and bought them here
lightbulbdepot.com

Good luck.

[j.e.simmons]

Here's a link to the BLB CFL bulbs for sale on Amazon.
http://www.amazon.com/Sunlite-SL220-...lite+blb+sl220

These are not exactly the ones I used. These are 20w - mine are only 15, so I don't see why they wouldn't work. I have six in my box to cover 8x10.

[john dean]

I have been reading this thread on led exposure boxes and I'm sorry but I just don't see a big downside to building and using the box Eric built for making platinum/palladium and gum prints. There are so many positive points and as for the unreliability of the bulbs it seems we have one experimenter, Sandy who is suggesting they are unreliable. I know Sandy has forgotten more about alternative than most of us put together but..... her experiment it seems combined traditional fluorescent tubes with the led lights in one unit. It seems to me that the heat alone of the tubes could have effected the stability of the led lights. Am I missing something? Seems to me the tests that Eric is doing would be a lot more reliable. So, Eric, how is it going? What I would look for is consistent exposure times for printing the same negative with the same process over the course of a year. For me if these new led bulbs lasted a couple of years until new potentially more reliable versions are available, I'm more than willing to build one of these.

[williaty]

The lifespan problems with affordable UV LEDs aren't unique to alternative process printing. The fact that they stop emitting UV after relatively little use is well documented in other industries where they're used to make paints and dyes fluoresce. Think places like dance clubs, laser tag, etc. Any place they like to make things glow. They're just cheap junk.

Similarly, there's no way to argue that the mismatch between the emission of cheap UV LEDs and the absorbtion iron-based alternative processes (cyano, Pt/Pd, VBD, Kali) isn't a problem.

Good UV LEDs, properly selected to match the common processes, are a great light source for alt process printing. However, they'll cost you a LOT more than using linear fluorescent tubes to achieve the same exposure times. The only upsides are no variation in output over the first few minutes they're on and reduced heat (but not by a lot).

[sanking]

John,

Yes, you are missing some important information.

With all due respect, I may have forgotten a lot, but "Gracias a Dios" I still remember a lot of important parts and my mind is still able to process new information. I actually installed a large number of LEDs of the type mentioned in Eric's test (exact same order number as I recall) in a large contact printer about two years ago, and the LEDs failed in less than a year. The outcome was not one that I expected, or desired, but I reported it, and stand by my conclusions that those type of LEDs are not reliable and IMO one would be foolish to waste a lot of time building a unit based on them. As I did. For that reason I will continue to recommend BL fluorescent tubes as the best choice for casual users, for three major reasons. 1) the technology of fluorescent tubes and ballast is well known, and reliable. 2) The BL tubes have peak radiation at wavelength of close to optimum for alternative printing (365 nm), the cheap LEDs are way off at about 395 nm, so result in lots of wasted energy. 3) The life expectancy of BL tubes is close to 10,000 hours, way more than the strip LEDs.

So, if you want to spend time building an LED unit that is sure to fail in a couple of years, be my guest. But why would you do that when you could make a unit of the same size with T8 BL tubes that would cost less, be more efficient, and last longer, than one you could make with LED strip technology?

And just for the record, the concept that LEDs do not produce heat is just way wrong. In the retro-fit I described where I combined both LEDs and BL tubes the greatest source of heat was the LEDs, not the tubes.

Nothing wrong with LED technology. As a previous post indicated.

"Good UV LEDs, properly selected to match the common processes, are a great light source for alt process printing. However, they'll cost you a LOT more than using linear fluorescent tubes to achieve the same exposure times. The only upsides are no variation in output over the first few minutes they're on and reduced heat (but not by a lot)."

And please note the comment, good LEDs will cost a " LOT more than using linear fluorescent tubes to achieve the same exposure times."


Sandy

I have been reading this thread on led exposure boxes and I'm sorry but I just don't see a big downside to building and using the box Eric built for making platinum/palladium and gum prints. There are so many positive points and as for the unreliability of the bulbs it seems we have one experimenter, Sandy who is suggesting they are unreliable. I know Sandy has forgotten more about alternative than most of us put together but..... her experiment it seems combined traditional fluorescent tubes with the led lights in one unit. It seems to me that the heat alone of the tubes could have effected the stability of the led lights. Am I missing something? Seems to me the tests that Eric is doing would be a lot more reliable. So, Eric, how is it going? What I would look for is consistent exposure times for printing the same negative with the same process over the course of a year. For me if these new led bulbs lasted a couple of years until new potentially more reliable versions are available, I'm more than willing to build one of these.

[Eric Biggerstaff]

Well, we have to try new things in order to advance - otherwise life just stands still.

The LED box is a good alternative, not sure why everyone says it is more expensive but that is OK. If you get the waterproof LED light strips peal off the rubber covering the lights, that turns yellow over time and makes the lights not work right. Also, it does produce heat, of course, but it is not a huge amount and good ventilation will do the trick. However, as I said in the beginning, this is not a pro-grade solution. It is great for a casual user but if you are producing lots of prints then invest in a more traditional unit. This was a challenge for me and it worked, it just is what it is.

[Eric Biggerstaff]

By the way, it only took me a few hours to build the unit, it is very easy. The lights are cheap, so even if I replace them every 2-3 years it is no big deal.

[williaty]

The LED box is a good alternative, not sure why everyone says it is more expensive but that is OK.

Two reasons:

1) Linear fluorescent lights are actually surprisingly cheap if you're using T8 tubes (and not T5 tubes)
2) The cheap LEDs in tape form wear out very quickly and are very poorly matched to alternative printing processes. To combat these problems you have to either a) replace the tape frequently which makes the LED the more expensive option or 2) use high quality LEDs that are well matched to the alternative printing processes and that makes the LEDs the more expensive options.


If you have fun making your light source out of LED tape, that's great. Challenging yourself by doing a project that you enjoy is a goal in itself. However, the fact that you overcame the challenge and had fun doing it doesn't mean that the project itself has better objective performance than other ways of achieving the same goal.