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

Eric Biggerstaff

21-May-2015, 15:01

I have been wanting to upgrade my UV light source to something a bit larger and more powerful. The commercial made boxes are just to expensive to justify given the amount of alt process work I do and even used ones were more than I wanted to spend. The DIY boxes I saw were nice and I have several friends who have made them, but they seemed a bit complex and at around $500 that was even more than I could invest.

So, I set a goal of creating a good DIY UV box for under $150 if I could. Searching YouTube I ran across this video:

https://www.youtube.com/watch?v=jLia59KfkSw

This seemed like a good solution and not overly complicated, which is good as I am NOT an electrician or handy with tools.

I did a search for UV LED lights and came up with these:

http://www.amazon.com/gp/product/B00NXDYMKU/ref=s9_simh_gw_p200_d0_i1?pf_rd_m=ATVPDKIKX0DER&pf_rd_s=desktop-2&pf_rd_r=0DD9EHFFETJBXJ9FS35X&pf_rd_t=36701&pf_rd_p=2091268722&pf_rd_i=desktop

There are many others but these were powerful and affordable, I decided that I needed two rolls of them with each roll being 5 meters long.

Based on advise from a friend (who is active on this forum), we decided to use a simple power source and again use 2 so there is plenty of power for the number of light, I went with these:

http://www.amazon.com/Power-Adaptor-Transformers-Supply-Lights/dp/B00K71VMCW/ref=pd_sim_200_24?ie=UTF8&refRID=010SWVG4SG1WJR2H1AY8

These provide plenty of power and are easy to work with, no need for fans or ballast as the LED's run cool.

Also, we adapted these to wire the lights to the power:

http://www.amazon.com/Connector-Single-Color-Strip-Adaptor/dp/B0085ZX8EM/ref=pd_sim_60_1?ie=UTF8&refRID=1A8TXKYN14J7DC1AP0VG

They are cheap so I bought a few but only needed two, one for each set of lights.

For the box, I simply used plywood I had on hand but if you were to purchase, I think you would maybe spend $20. Also, I bought a hinge and a knob for $12 total so my net investment in materials was around $100 not including tax and shipping.

So far so good.

Using the ideas shown in the video, my friend and i created the light panel. Ours was a little different but as you can see in the pics, it works just fine. I won't go into construction details as you can piece that together based on the video but one thing learned is that the LED's measure 3/8" of an inch wide so we spaced them 1/2" inch apart. This provides a very smooth even light and there is space between the strips that would allow me to add lights if I wanted to.

The entire build took about 8 hours total spread over 4 days, so not a big deal at all.

The LED's are attractive to use as they are cheap, no ballast required, have a 50,000 hour lifetime, run cool, and quickly light when the timer is tripped (mine have a 2 second lag so not bad).

Now, on to testing!

I will report on the results later this weekend.

Here are the pics:

Eric Biggerstaff

21-May-2015, 15:03

And a couple more:

Peter De Smidt

21-May-2015, 15:30

Looks good! Those led strips are certainly handy. How hot do they get? When I made my light source for my scanner, I used similar LED strips, but I mounted them to an aluminum heat sink.

21-May-2015, 15:32

Looks good to me, testing results is what matters.

Eric Biggerstaff

21-May-2015, 18:09

A few more details, my light panel is 5.5 inches from the base of the box, when I place my printing frame into the unit, the neg rests about 4.5 inches from the lights as my contact frame is about an inch deep. Also, the inside of the box is painted white of course. The panel measures 17"x 22" which will allow print of around 16" X 20" if I ever get brave enough to go that large.

I just ran some tests and found that a palladium print on Arches will give me a min time / max black at 6 minutes. I used a piece of Pictorico as the film base as I print mainly digital negs with palladium.

This is not bad and is certainly a large improvement over what I was using, however I would like to knock another couple of minutes off of that time. To so, I could lower the lights closer to the neg or increase the number of lights. I may invest another $25 for an additional roll of lights to increase the total light output but for now, really, 6 minutes is pretty darn good.

A nice feature of this type of UV box is you can make them as large or as small as you like since the LED strips can be cut. They come in 5 meter rolls with a self adhesive backing so adding or removing lights is a breeze.

I will need to re-calibrate my negs now that I have a new light source, but that should not be too difficult.

Eric Biggerstaff

21-May-2015, 18:12

The heat output is very minimal, I left a bank on for 6 hours the other day and while there was a feeling of warmth, they were in no way hot. Even the power packs stay cool.

Peter De Smidt

21-May-2015, 18:16

That's great. I'd add more lights. If you get too close, the light will get uneven.

Eric Biggerstaff

21-May-2015, 18:20

Agree Peter. One thing, these lights are VERY even as they are not pinpoints, but more diffuse. It maybe the waterproof coating on them but I was very impressed by the quality of the light.

prendt

22-May-2015, 05:33

Steve Goldstein

22-May-2015, 06:04

Thanks for this Eric. Those power supplies and adapter cables are just the thing I've been looking for (not very hard) for a split-printing LED-based 5x7 head I've been planning for my Beseler MX45.

Michael W

22-May-2015, 06:42

Looking at the photos it appears you did some soldering to link the strips? This type of homemade box is of interest to me but I've no idea how to solder. I'm wondering if this step is necessary. Had a look at the Amazon link to the strips and got the impression that the strips can link up if you line them up next to each other and use some type of connecting clips. Was the soldering used because you were spacing the strips wider apart?

Eric Biggerstaff

22-May-2015, 06:53

I think you could use the connectors to chain link the strips, but you would need to purchase a bunch of them which would drive up the cost a bit. I had a link to the connectors in the first post. I am not a soldering expert as well, but my friend is good (not expert but you really don't need to be) and together we knocked out the soldering in about 15 minutes. With the low financial cost, it is possible to play with different ideas and find one that works for you.

Eric Biggerstaff

22-May-2015, 07:07

Bruce Schultz

22-May-2015, 08:09

That figures. I built mine a few months ago with tubes, but this would be much easier and cheaper. I'm going to explore supplementing my tubes with some LED strips.

Fr. Mark

22-May-2015, 10:03

Maybe the UV LEDs in strips are a new thing. I made my UV exposure unit with bug zapper bulbs (6) and the tube sockets from topbulb.com and ballasts from Lowes or Home Depot, I'd have to look at the notes but I think it was well under $100. Wire nuts and press fit connections, no soldering, but I'm not afraid of soldering either. No idea which has more UV output. I finally made an in camera negative the other day that worked well with Dr. Ware's new cyanotype last night. With my six bulbs took 2 minutes to get the highlights right through the Pyrocat HD developer on Ektascan B/RA. Actually 1-2 bulbs would be enough for the 4x5 negative. Now we head to 5x7 and 8x10 and perhaps, someday, 14x17 Carbon prints.

If I ever build another, it will likely be this sort of design. I don't like the fragility of the tubes.

Fr. Mark

22-May-2015, 10:05

I forgot to say, I'd hoped to do a UV LED approach but it was not obvious how to get the right LED's etc and I sure didn't want to start with loose LED's and wire/solder an array to cover 14x17. T8 bug zapper bulbs and ballasts with wiring instructions is about as close to an electrical engineer as I want to get most of the time.

DJG

22-May-2015, 10:47

Very clever, thanks for the ideas Eric.

dtheld

22-May-2015, 11:09

Eric,
Great setup, especially since we are suffering from a lack of sunshine this month. It will be interesting to see your results.
Dave

James Pierce

23-May-2015, 10:33

I built something very similar last year using the same approach - Almost 2.5 rolls of UV to make an 11x14 light source (I had a physical space constraint in that darkroom)... I used a large heatsink as the backing for all the LEDs and built a power supply in to the rear etc. In retrospect that may have been rather overkill as your setup shows. Mine doesn't even get warm to touch with the heatsink and fan setup I made. Print times for me are around 3-4 min typically. I can't imagine anything but LED for UV these days.

Ian Leake

23-May-2015, 11:41

I've toyed with the idea of an LED light source, but haven't got farther than thought experiments. Thanks for sharing!

denverjims

21-Jun-2015, 21:18

I built a fluorescent bulb box a couple of years ago. Felt it was a pretty decent rig until i saw Eric's LED design.

Now I know how the guy felt who had just bought a new horse and buggy rig and then spotted a new fangled motor car come around the corner. Anyone want to buy a buggy whip? LED definitely the way to go now. No need to design to deal with the heat and cheaper lamps & power supply.

Nice job Eric!

Michael Mutmansky

22-Jun-2015, 10:06

This is not bad and is certainly a large improvement over what I was using, however I would like to knock another couple of minutes off of that time. To so, I could lower the lights closer to the neg or increase the number of lights. I may invest another $25 for an additional roll of lights to increase the total light output but for now, really, 6 minutes is pretty darn good.

I hadn't noticed this before, or I would have commented earlier...

Moving a light source that is a planar source (which this acts effectively as) will have very little impact on the exposure you get on the print within the reasonable distances you are thinking (up and down a few inches).

This is a result of the integrative math associated with a distributed light source and any given point on the paper. If you think if if this way, from any given point on the paper, there is a view of about 180 degrees in all directions. As you bring the light closer, the lights way out at the edges become less visible, and the lights in the center of field become stronger (closer) and the effect effectively cancels each other out (because there are a lot more out in the edges than in the middle).

Here is essentially the exact same effect as applied in electrical fields in a capacitor:

https://en.wikipedia.org/wiki/Capacitor#Parallel-plate_model

The key words in that write-up are "Assuming that the width of the plates is much greater than their separation d, the electric field near the centre of the device will be uniform with the magnitude E" and the formula does not have the distance between them as a variable.

However, there is a drawback to moving the light bank closer; the LEDs may have non-uniformity in their individual light beams (almost certainly, in fact), and you want a lot of overlap of the source beams to avoid being able to see the light beam patterns in the prints.

Here is a photo of a typical strip of LEDs (not the ones you specified, to be sure), and you can see that each individual one has a fairly narrow beam to it:

here (https://www.google.com/search?q=led+light+beam+angle&rlz=1C1ZMDB_enUS561US561&espv=2&biw=1852&bih=874&source=lnms&tbm=isch&sa=X&ei=yjiIVebJM4b6-AG98oDICw&ved=0CAcQ_AUoAg#tbm=isch&q=led+light+beam&imgrc=65kWC7uTcr01vM%253A%3BQLyLo6yXh2vh4M%3Bhttps%253A%252F%252Fwww.superbrightleds.com%252Fimages%252Fuploads%252Fled-flexible-light-strip-snfls-x480-1.jpg%3Bhttps%253A%252F%252Fwww.superbrightleds.com%252Fmoreinfo%252Fside-emitting%252Fside-emitting-led-light-strips-led-tape-light-with-29-smds-per-ft-5mm-dip-led%252F867%252F%3B650%3B457)

If I were planning to do an LED light box, I'd put the LED lights as close together as possible to overlap the sources as much as possible.

Eric Biggerstaff

23-Jun-2015, 17:31

I have been using it for several weeks now and no complaints, the light is even and I have good exposure times. I might have added a third roll of lights and have them close together as was done in the video I posted the link to, but just didn't see the need at the time. The distance seems fine and I have no reason to change it. The lights I am using are waterproof and have a thick clear "rubber" coating over them which helps diffuse the light which I think is an added benefit.

But, all in all, I think it project was a success and I would do it again. I could go back and add another roll of lights but for the time being I have no plans to, it would add about $30 more to the project.

sanking

25-Jun-2015, 19:53

I agree with Michael that it would be best, in terms of short exposure, to space the LEDs as close as possible. That has certainly been my experience in building banks of BL tubes.

Now, what I would like to know is this. If we were to compare a bank of T8 Bl tubes, with appropriate ballast, spaced as closely as possible, with a bank of LEDs also spaced as closely as possible, which unit would put out more effective radiation for alternative processes like pt/pd? Is this something we could from the specifications, or would it be necessary to actually test this with a specific process?

Has anyone every made a direct comparison of this type?

Sandy

SergeiR

26-May-2016, 12:36

I had tested one UV LED strip (not one in link, but different) spreaded across 20x24 area, roughly 3 inches depth couple weeks ago. To get decent exposure on vandyke with Xray negative took me about 16 minutes. About to rebuild whole thing with secondary strip and reflective sides, if hands will be ok this weekend. Funny how we arrived at nearly same idea at nearly same time, year apart ;)

timparkin

16-Jun-2016, 12:01

Kevin J. Kolosky

7-Jul-2016, 12:24

Maybe I missed reading it, but would a variation of this work in an enlarger.

seezee

7-Jul-2016, 12:32

Maybe I missed reading it, but would a variation of this work in an enlarger.

There's a thread dedicated to that topic (http://www.largeformatphotography.info/forum/showthread.php?35253-UV-bulb-in-enlarger). Précis: too many obstacles to make a UV enlarger either practical or safe.

Greg

7-Jul-2016, 16:48

Précis: too many obstacles to make a UV enlarger either practical or safe.

In the 1970s at the Rochester Institute of Technology, I believe one working 8x10 UV enlarger was built and used. I think it had a sliding head with a conventional bulb and another head with a UV light source (obviously not LEDs!), and was shared by the Photography Department and the people who printed circuit boards. Never saw it, only heard stories about it. Back then a lot of experimental Photographic equipment were constructed... Materials costs were offset by manufactures donating "tons" of equipment and parts. There was a "Cage" that any student could borrow almost type of photo equipment from for free. Ah, those were the days....

Fr. Mark

7-Jul-2016, 19:13

I've thought about this, too. Lenses would be hard to make (you might need quartz not regular glass), detecting focus would be hard, and like with regular enlargers, intensity of the light falls off as the square or is it cube of the distance? and most UV processes need major light intensity. I think we're stuck with either making the negative the size you want with your LF or ULF or UULF camera in the first place or scanning and printing a smaller negative to enlarge or making an enlarged positive then contact printing that as a negative or similar approaches to getting a larger negative and contact printing.

koraks

3-Aug-2016, 13:31

My apologies for kicking this thread again, but the OP being over a year old is an advantage in this case.

Can anyone, preferably (also) Eric comment on the useful lifetime of these UV LED strip lights? If I follow the link to the LEDs as advertised on Amazon, I notice a few people mentioning that they fade to white in a period as short as two months, rendering them useless for UV applications. It's unclear if this is with continuous use or intermittent use, which would be a more typical situation for contact printers.

sanking

3-Aug-2016, 14:15

That is a good question. My own experieces strongly suggests tht the life of these UV LED strips is very short.

Here is my expereince. A little more than a year ago I installed over 500 watts of the 395 nanometer LED strips to supplment the existing BL tubes in a large Ryonet X-Vactor. I described the retrofit on the carbon forum I moderate on Yahoo. Early tests indicated that the LEDs shorted exposures significantly, by more than 1/2 stop.

A few days ago I tested the unit, after noticing that the color of many of the LED lights had faded significantly, and discovered that exposure times with and without the LEDs was virtually identical, 2.4 units per second with only the BL tubes, 2.2 unitss per second with the BL tubes and LEDs.

In retrospect I believe that it would have been far better for me to have added more BL tubes, not the LEDs, since BL tubes have a history of very long life. I personally won't fool with LEDs anymore untiil the technology is better.

Sandy

My apologies for kicking this thread again, but the OP being over a year old is an advantage in this case.

Can anyone, preferably (also) Eric comment on the useful lifetime of these UV LED strip lights? If I follow the link to the LEDs as advertised on Amazon, I notice a few people mentioning that they fade to white in a period as short as two months, rendering them useless for UV applications. It's unclear if this is with continuous use or intermittent use, which would be a more typical situation for contact printers.

Peter De Smidt

3-Aug-2016, 14:27

It's likely that high-end single LEDs, such as from Cree, would be much longer lived if properly installed and driven.

Fr. Mark

3-Aug-2016, 21:07

I've been skeptical about UV-LEDs. Most LED packages are plastic. Most plastics degrade under intense UV light.
I'm hopeful that LEDs will eventually supplant fluorescent bulbs for efficiency and lack of mercury in the house, but for now...I'm still on my first set of bug zapper bulbs and while I don't use them as much as I'd like to yet nor keep as rigorous records as I should, I suppose, they have not declined that I can tell.

Tin Can

3-Aug-2016, 22:02

Another thread 2 days ago linked to high end and high power Cree LED with glass. The. Fish and coral reef folk are using them increasingly.

I plan to get some of these ASAP. Which means next winter. For UV box and bicolor enlarger head.

http://www.ledsupply.com/blog/#article/485

LEDs are getting better every 6 months. The strips are garbage now.

The link is 18 months old. The seller is already on second generation of the 'latest' UV LED.

williaty

3-Aug-2016, 23:37

http://www.ledsupply.com/blog/#article/485

LEDs are getting better every 6 months. The strips are garbage now.

The link is 18 months old. The seller is already on second generation of the 'latest' UV LED.

Your link doesn't point to anything about UV. Can you see if you can figure out what the link was supposed to be?

williaty

4-Aug-2016, 00:01

Looking through the LED Supply website, they're doing basically the same thing as everyone else and offering 400-410nm and 410-420nm LEDs and calling them "UV". The following graph is from From ultraviolet to Prussian blue: a spectral response for the cyanotype process and a safe educational activity to explain UV exposure for all ages J. Turner,* A. V. Parisi, N. Downs and M. Lynch Photochem. Photobiol. Sci., 2014, 13, 1753 DOI: 10.1039/c4pp00166d. The x-axis is wavelength in nm and the y-axis is fraction of sensitivity compared to peak. The 3 lines are three different coatings. The 410-420nm LED is going to produce basically no exposure and even the 400-410nm LED is going to be extremely inefficient. LEDs with emission peaks around 380nm are readily available and I'm fairly sure I once considered buying a flashlight with a 365nm peak. UV curing LEDs go as low as 320nm but I'm not sure about availability outside the OEM chain. While those LEDs might be somewhat more expensive, the fact that you'd need a quarter or an eighth the number of them would certainly offset the price. You'd see further savings in reduced power supply demands. You'd also have even less heat.

https://c1.staticflickr.com/9/8580/28725488926_b2ac02f100_b.jpg

Tin Can

4-Aug-2016, 00:26

Your link doesn't point to anything about UV. Can you see if you can figure out what the link was supposed to be?

My mistake. Rereading, the spectrum is too high for Alt Process but IS fine for SG enlarger head when combined with green and varied between the 2. Guess we need industrial LED because if you dig deeper there are options.

http://www.ledsupply.com/leds/cree-xlamp-xt-e-royal-blue-leds

Tin Can

4-Aug-2016, 00:49

Her is where I read of lower spectrum LED. Violet and UV LEDs are available in wavelengths ranging from 360nm to 420nm (http://www.ledsupply.com/blog/ultra-violet-uv-high-power-led-overview/)

Then this, page 3. (http://www.ledsupply.com/content/pdf/leds-semiled-uv_documentation.pdf)

SergeiR

4-Aug-2016, 05:21

Simplest of simple tests for me was - plug in strip and see if white paper sheet looks like it glowing ;)

I know, not as technical and cool, but hey... its works.. I can print vandykes and kallitypes quite happily :) Not seconds exposure, but not hours either.

Eric Biggerstaff

4-Aug-2016, 06:44

Mine are still plugging away with no issues, same print times as when I first built it and I have done several hundred prints now. If they change, no big deal, just build another strip board and drop it in.

Remember, this was never intended to replace a "professional" unit. It is a simple and fun project for the occasional printer (like me) that allows someone to create nice prints with little investment. I am not an engineer and don't pretend to be one. My feeling is just to try it and see if it works, in this case it did for me and the solution fits my needs nicely.

koraks

4-Aug-2016, 11:29

I knew this would be the right place to ask, and lo and behold, several very useful responses, great!

As I understand there are two issues to deal with.

Firstly is the emission spectrum of the light source. All the cheap strip leds that are labeled as UV have their peak around 400nm - a bit on the long side, but it should work. Eric's experience demonstrate that it indeed does. Going by Sandy King's writeup on UV light sources (easily found through google), I expect that UV leds will yield a somewhat shorter tonal scale than cfl's. This can be an advantage, if the negatives that are printed have a shorter tonal scale. I suppose it's a matter of dialing in the negative to the light source. I also suspect, although this is conjecture on my part, that these cheap UV leds are in fact white leds with a coating that fluoresces in the UV spectrum. If this is an organic coating, then it will degrade, which would explain why some users report the leds fading to white over time. I also notice that in the (scarce) specifications of Chinese UV led strips, the actual led chips used are marketed by their manfacturers as white leds. This would support my hypothesis, but more concrete evidence I don't have.

This brings me to issue two: longevity. Apparently experiences are mixed. Sandy reports an apparently swift degradation in output, while Eric still uses the original light source in his setup successfully. Perhaps the volume is an important factor; I suspect that Sandy may make many thousands of prints in the same period when Eric makes a few hundred. I suppose I'm somewhere in between, but closer to Eric than to Sandy.

I think I'm just going to give it a try with the led strips, but I think I'll construct the exposure unit in such a way that I can retrofit it with cfl tubes if the leds turn out to be a disappointment. I also considered Eric's suggestion of simply replacing the leds when they wear out. Given the manageable costs, this would cost me about $70 in the A3-sized exposure unit I'm planning to construct, which will use about 900 (3 rolls of 5 meters and 300 leds each) individual leds. I also reckon that this power density should yield fairly short printing times, as the power density would be a few times as much as in Eric's setup. I'm planning to have a 1cm pitch between the led strips. As it is, this is just a rough idea for which I have only done some preliminary calculations, but by the looks of it, it should be feasible. And it's not a very expensive experiment, as the material costs amount to about $100.

Eric Biggerstaff

24-Aug-2016, 11:21

williaty

24-Aug-2016, 11:31

Based on Randy's post I was doing some research and this winter I am going to re-build my light bank and try those high output Cree UV LED stars, I just need to figure out how many I need to cover the 16X20 bank. Should be fun!

You need to look at the emission spectrum of the LEDs vs the sensitivity of the process you're going to use. For Cyanotype, you would ideally be putting most of your energy between 300nm and 360nm which means there's VERY POOR overlap between the 400-405nm LEDs. The linear fluorescent BL and BLB tubes are actually much, much better suited to alt process printing than the 400-405nm LEDs. Y-axis is response, X-axis is wavelength in nm.

https://c1.staticflickr.com/9/8580/28725488926_b2ac02f100_b.jpg

Eric Biggerstaff

24-Aug-2016, 13:12

Will check, I don't do cyanotype, just plain old fashioned platinum / palladium.

Thanks!

williaty

24-Aug-2016, 13:32

Will check, I don't do cyanotype, just plain old fashioned platinum / palladium.

Thanks!

Pt/Pd will be roughly the same. All the Fe-based processes will. Carbon (and salt, I think) will respond more to longer wavelengths.

Eric Biggerstaff

24-Aug-2016, 14:17

Thanks again, this has been a great help, I will look for lights in the 300nm to 360nm range.

williaty

24-Aug-2016, 14:52

The linear fluorescent tubes that are marked BL or BLB are usually within spitting distance of 350nm, so they work well. Check out http://unblinkingeye.com/Articles/Light/UVC1/uvc1.html and http://unblinkingeye.com/Articles/Light/UVC2/uvc2.html

That website is actually fairly useful. The page about printing is at http://unblinkingeye.com/Articles/Light/light.html

Paul Cunningham

24-Aug-2016, 16:37

I have 4 minute print times with LEDs and pt/pd, using off the shelf LEDs like those originally posted. You can't want much faster than that, can you?

Sent from my iPhone using Tapatalk

williaty

24-Aug-2016, 16:47

I have 4 minute print times with LEDs and pt/pd, using off the shelf LEDs like those originally posted. You can't want much faster than that, can you?
You can print with candles if you throw enough of them up there. Doesn't mean they're well matched to the goal. The issue is that the mismatch between their emission and the process's sensitivity means you're spending a lot more on LEDs and electricity than you'd need to if you could buy LEDs with a shorter wavelength. If you're using 405nm LEDs, you could cut the number of LEDs and the power by 75% if you could buy 350nm LEDs. That means the LEDs aren't more efficient and are generating more heat than the T8 BL or BLB tubes would be.

Tin Can

24-Aug-2016, 16:51

You can print with candles if you throw enough of them up there. Doesn't mean they're well matched to the goal. The issue is that the mismatch between their emission and the process's sensitivity means you're spending a lot more on LEDs and electricity than you'd need to if you could buy LEDs with a shorter wavelength. If you're using 405nm LEDs, you could cut the number of LEDs and the power by 75% if you could buy 350nm LEDs. That means the LEDs aren't more efficient and are generating more heat than the T8 BL or BLB tubes would be.

Really? Prove the total power usage is less with BLB.

williaty

24-Aug-2016, 17:04

Really? Prove the total power usage is less with BLB.
T8s with narrow emission spectra (like BL and BLB) range between 90 and 100 lumens per Watt. LEDs with phosphor re-radiation (like the 405nm LEDs) typically are in the 90 to 120 lumens per Watt. If we assume the worst T8 at 90Lm/W and the best LED at 120Lm/W, the LEDs are only 33% more efficient at emitting photons. However, the photons they emit are about 75% less efficient at exposing the iron-based alternative processes. So you need about 4x as many LED lumens as you do T8 lumens. Being generous and assuming that the LEDs are about 30% more efficient, you're still going to have to put in ~2.8x as many Watts to get the same exposure rate if you hold all other variables equal.

I would be very curious, though, if due to shape, people are managing to arrange the LEDs in a more efficient pattern of coverage and thus move the LED array closer to the print and gain some printing speed back by doing so.

sanking

24-Aug-2016, 17:44

T8s with narrow emission spectra (like BL and BLB) range between 90 and 100 lumens per Watt. LEDs with phosphor re-radiation (like the 405nm LEDs) typically are in the 90 to 120 lumens per Watt. If we assume the worst T8 at 90Lm/W and the best LED at 120Lm/W, the LEDs are only 33% more efficient at emitting photons. However, the photons they emit are about 75% less efficient at exposing the iron-based alternative processes. So you need about 4x as many LED lumens as you do T8 lumens. Being generous and assuming that the LEDs are about 30% more efficient, you're still going to have to put in ~2.8x as many Watts to get the same exposure rate if you hold all other variables equal.

I would be very curious, though, if due to shape, people are managing to arrange the LEDs in a more efficient pattern of coverage and thus move the LED array closer to the print and gain some printing speed back by doing so.

Having compared a very large array of 395 nanometer LEDs with a bank of 350 nanometer BL tubes I am total agreement with your conclusions.

It is possible to move the LED array closer to the printing frame, of course, but if you do it will be necessary to install more of them to get even coverage. The same principle and rule applies to BL tubes.

Sandy

sanking

24-Aug-2016, 18:05

Follow up comment. In an earlier message I wrote.

A little more than a year ago I installed over 500 watts of the 395 nanometer LED strips BETWEEN existing BL tubes in a large Ryonet X-Vactor. I described the retrofit on the carbon forum I moderate on Yahoo. Early tests indicated that the LEDs shorted exposures significantly, by more than 1/2 stop.

A few days ago I tested the unit, after noticing that the color of many of the LED lights had faded significantly, and discovered that exposure times with and without the LEDs was virtually identical, 2.4 units per second with only the BL tubes, 2.2 unitss per second with the BL tubes and LEDs.

A few days ago I pulled the LED array out of the X-Vactor and replaced it with nine 350 nanometer tubes, placed BETWEEN the original tubes, i.e. same arrangement that existed with the LEDs.

The result in printing speed was dramatic.

a. Original unit with only the 8 BL tubes. One unit of exposure was equal to 2.4 seconds.
b. Original unit with the 8 BL tubes plus the large array of 395 LEDs. One unit of exposure dropped to two seconds of time, when new.
c. Original unit with the 8 BL tubes, plus the extra BL tubes installed between the original tubes. One unit of exposure equals 1.1 second.

I am very interested in new technology and would like to encourage the use of LEDs in alternative printing units. But for me, the bottom line at this point is that the 350 nanometer BL tubes are still the most efficient, and economical, way to build a high quality exposure unit for alternative printing. I would also add that I found the retrofit of the BL tubes far easier than the retrofit of the LEDs, in large part because in the installation of the LEDs I had to do a lot of soldering.

Sandy

Tin Can

24-Aug-2016, 18:17

I like the neat agreement of empirical and calculation.

Thank you Sandy King and Williaty.

Niall

1-Oct-2016, 14:56

An interesting thread- lots of useful stuff here.

Somewhat belatedly, I discovered this thread part-way through construction of my own LED UV box.

I've got as far as cutting the strips and attaching them to the wooden panel, but am now alarmed about the prospect of their potentially short life-span.

Immediately, I'm struggling to solder wires to the copper terminals- it requires a degree of soldering finesse hitherto unknown to me.

Once/ if I get it connected, I'll post some pics / reviews about how it went and works.

Thanks to all,
Niall Bell.

macandal

9-Dec-2016, 13:49

I'm sorry but I know nothing about light or building anything, let alone, building materials or tools, in other words: I know NOTHING.

UV (ultra violet) light = black/blue light?
UV = 450 nm?
What is an "nm"?
Have there been any improvements in LED UV strips since, er..., October 1, 2016?

I'm sure I'll have more questions as I get ready to build one of these myself, but, for now, this is it.

Thank you.

williaty

9-Dec-2016, 15:08

I'm sorry but I know nothing about light or building anything, let alone, building materials or tools, in other words: I know NOTHING.
UV (ultra violet) light = black/blue light?
No. Ultraviolet is what lies beyond blue and violet in the rainbow. It's invisible to humans. Lamps that produce UV are commonly referred to as "black lights" because they don't make light we can see. There are also so-called "black light blue" lamps which "leak" a little blue/violet light that we can see.

UV = 450 nm?
Ultraviolet light (https://en.wikipedia.org/wiki/Ultraviolet) officially extends from 10nm to 400nm.

What is an "nm"?
nm is the abbreviation for nanometer, a measure of length that is TINY. (https://en.wikipedia.org/wiki/Nanometre) It is commonly used to measure the wavelength of electromagnetic radiation (https://en.wikipedia.org/wiki/Electromagnetic_radiation) such as visible and UV light.

Have there been any improvements in LED UV strips since, er..., October 1, 2016?
No. The reasonably priced LEDs still do not emit much UV light in the range alternative processes need and still die pretty quickly. Expensive LEDs do a fine job, though. It's still better, more efficient, and cheaper to use normal linear fluorescent UV-emitting tubes.

sanking

9-Dec-2016, 15:25

No. Ultraviolet is what lies beyond blue and violet in the rainbow. It's invisible to humans. Lamps that produce UV are commonly referred to as "black lights" because they don't make light we can see. There are also so-called "black light blue" lamps which "leak" a little blue/violet light that we can see.

Ultraviolet light (https://en.wikipedia.org/wiki/Ultraviolet) officially extends from 10nm to 400nm.

nm is the abbreviation for nanometer, a measure of length that is TINY. (https://en.wikipedia.org/wiki/Nanometre) It is commonly used to measure the wavelength of electromagnetic radiation (https://en.wikipedia.org/wiki/Electromagnetic_radiation) such as visible and UV light.

No. The reasonably priced LEDs still do not emit much UV light in the range alternative processes need and still die pretty quickly. Expensive LEDs do a fine job, though. It's still better, more efficient, and cheaper to use normal linear fluorescent UV-emitting tubes.

To follow up on this, in October I was in Nanjing, China at a Symposium on alternative photography. One of the printing facilities at the Nanjing Institute of the Arts had several exposure units equipped with the more expensive LED lights, and they were very efficient. The guy who builds these units (from Hangzhou), and sells a lot of them now on ebay with tubes, was at the Symposium and talked about production. I expect that within a relatively short period of time the units on ebay will be equipped with the higher quality LED lights. Makes sense that they would use LEDs since a lot of the tubes are broken in shipping.

From the perspective of efficiency, and easy of construction, 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. The tubes are both very efficient and very inexpensive, last a very long time (5000 hours or more) and the wiring technology widely known and understood.

Sandy

macandal

9-Dec-2016, 17:01

No. Ultraviolet is....Thanks.

macandal

9-Dec-2016, 17:08

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 (https://www.amazon.com/dp/B000TZWIQK/ref=psdc_495232_t1_B00FZQ9HY4)

Over one of these:

BL (https://www.amazon.com/GE-35884-F15T8-Fluorescent-Black/dp/B00FZQ9HY4/ref=cm_cr_arp_d_product_top?ie=UTF8) ???

Or even over a regular T8 UV light?

Thanks for all your help.

stawastawa

9-Dec-2016, 19:08

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

williaty

9-Dec-2016, 19:51

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

9-Dec-2016, 20:23

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

BLB (https://www.amazon.com/dp/B000TZWIQK/ref=psdc_495232_t1_B00FZQ9HY4)

Over one of these:

BL (https://www.amazon.com/GE-35884-F15T8-Fluorescent-Black/dp/B00FZQ9HY4/ref=cm_cr_arp_d_product_top?ie=UTF8) ???

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

9-Dec-2016, 21:34

williaty

9-Dec-2016, 22:23

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

10-Dec-2016, 07:44

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

11-Dec-2016, 15:33

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.info/forum/showthread.php?107360-Another-UV-Light-Box-(16x20)&p=1069353#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

12-Dec-2016, 15:46

12-Dec-2016, 18:54

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/13759696@N02/albums/72157635019029286/with/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.

Fr. Mark

12-Dec-2016, 19:18

I put the ballasts outside on mine. I used 6 18" t8 tubes. I've never printed bigger than 8x10 yet but I had in mind 14x17 when I built it.

denverjims

13-Dec-2016, 07:59

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.

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?
How much space should there be from the lights to the bed where the negative/paper will rest?
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?
How does one settle on the wattage for the candles?
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.

1. & 2. The main problem is that if the paper is too close to the bulbs, you will get stripes due to the uneven illumination. Because of the inverse square law, the closer you are the greater the differences in illumination % is between where the bulb is closest to where the spaces between bulbs provide little UV. I chose about 5 1/2" from the bottom of the bulbs to the floor of the box and that seemed to be OK. It was about the minimum of the distances that were recommended.

Also, you need to take into account the thickness of the holder which will hold the sandwich of the negative and the sensitive paper. If you are just using a piece of glass then it will not be very thick but many of the commercial types (like those available from the Formulary) raise the paper an inch or more above the floor of the box. This means the box has to be that much taller.

Finally, if you put the ballasts outside the box, it can be shorter. In most builds I've seen, including mine, the ballasts are inside the box and, so, add to the height. Putting the ballasts inside keep you away from the heat and the potential for contact with the electrical connectors.

3. 'jp' answered that one pretty well. I chose 12 lamps as they seem to cover 16x20. There is also the issue of the tombstones having width which limit how closely you can pack them. I have seen some designs which offset alternate bulbs which allow a little closer packing. Of course, the closer you pack them together, the more heat generated in a small space - hence increasing the need to dissipate the heat with a fan.

4. Most bulbs available are what they are in watts (most common T8's seem to be 15). You pack as many into the space as you can (to minimize the exposure times) and that's the wattage.

5. If the ballasts and the bulbs are inside the box, you will be well served to have a fan. A lot of heat will cook the electronic ballasts (and they do get hot). That is why so many fluorescent light fixtures are made of metal. The fixture becomes the heat sink to dissipate the heat. But inside a wood box (the most common material used and a fairly efficient insulator) the heat normally can't move away fast enough by itself. Also, the bulbs generate a fair amount of heat by themselves. Too much heat could affect the chemistry on the papers. A fan is the normal solution. Again, if the ballasts are outside the box, it will decrease the amount of trapped heat.

Hope this helps some, Jim

denverjims

13-Dec-2016, 10:25

macandal,
I had not looked at the pictures that 'jp' linked to when I made my previous response but I wanted to point out that he used that offset alternating technique I spoke of in mounting his bulbs which allowed him to pack more bulbs into a smaller space. This gives more light and some more even coverage.

My mounting was side-by-side as you can see by the pictures I posted with my project build (linked to in a previous posting in this thread). This did not allow me to pack the bulbs as tightly as 'jp' did but, since I was trying to cover up to 16x20, I would have required an additional ballast if I added any bulbs. I felt that the decrease in exposure time was not worth the additional cost. I had calculated that my distance from bulb to base was sufficient to avoid bands / stripes even with the slightly increased center-to-center separation of the bulbs over the other technique.

macandal

17-Dec-2016, 12:24

Tin Can

17-Dec-2016, 13:14

You may not get an answer. This forum usually avoids any electrical advice. Liability comes to mind.

We are seeing even boxed new items burst into flame.

DIY is a solitary pursuit, best accomplished by through personal research until the researcher is sure of their capability.

Note that someone here stated fluorescent bulb fixtures are usually metal, probably for heat sink and fire resistance. Even metal can burn...

I recommend everybody have at least 2 fire extinguishers of the proper type for their situation.

I also recommend unplugging from the wall as much as you can and inspecting all electrical devices as often as you can.

Safety First.

I have put out enough home and industrial fires to fear them. Lost 2 family to house fire recently.

I was trained yearly on big outdoor gasoline fires for my indoor job.

I am not a Fireman nor emergency worker.

sanking

17-Dec-2016, 13:53

Okay guys. Thank you for all your answers/suggestions, but I'm a bit confused here. jp says, in post #70, in relation to the ballast/fan question, that it does not get very hot, and, I'm assuming, he's suggesting that I don't really need to add a fan to my box. Yet, others have said that it does indeed get hot and that a fan is necessary. Which is it? Given that the exposures will only be a few minutes long, do I need the fan or not?

Thank you.

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

Why not think of it this way? Installation of a fan is a relatively simply procedure that may improve the safety of your light box and help to give more consistent exposures by keeping the temperature down. There is absolutely no down side to a fan in a light box, except the possibility of a mistake in wiring.

Yes, you may be able to get away with no fan, 1) if your frame is made of metal and can serve as a heat sink, 2) if tube spacing is far apart, and 3) if exposure times are always short. If you look on ebay you will find that many of the exposure units sold for the screen printing industry fit this description.

However, if you are making a box with a wooden frame, with very close spacing of the tubes, with the ballast enclosed and not well ventilated, and your exposures are long, there can be enough heat build-up to reduce radiation and slow down your exposures, and cause enough excessive built-up of heat to be a major safety issue.

Sandy

17-Dec-2016, 14:32

Given that a kid's easy-bake oven is basically a box with a 100w bulb in it. Given that a coffee burner (not the coffee maker element) is generally a 60-100w heating element, and we are making boxes that consume similar power, it makes sense to have a ventilation fan whether it's needed or not. Err on the side of caution, not how you exactly intend to use it.

I ran mine for a few hours after I built it to verify it didn't get warm or malfunction. If you think you are only using it a few minutes at a time, consider the results of if you left it on by accident overnight. Mine is also plugged into a gralab 451 timer which starts up off, and I leave it on a turned off power strip when not in use.

I think traditional fluorescent fixture are metal because the original magnetic ballasts used to sometimes self destruct and the metal was good safety. Contemporary electronic ballasts don't fail as dramatically.

denverjims

17-Dec-2016, 20:53

"A man oughta do what he thinks is best." John Wayne; "Hondo"

...women too.

j.e.simmons

18-Dec-2016, 08:16

denverjims

18-Dec-2016, 18:44

I only print 8x10 and successfully made a light box with BLB CFLs. They have ballast built in, so the only wiring required was between common flush sockets. I left the ends of the box open, so I have little heat buildup, even with some of the long exposures required.

Great. Didn't know that they existed. Sounds like a better solution.

That's the thing about technology changing as rapidly as it does. Any advise you receive today about what a good solution might be can be made obsolete by another new product being made available to us. Someday soon, hopefully, LEDs will be made more permanent as UV light sources and it will, again, be the way to go. With their small emitter size, efficiency and low heat output; it would be perfect. That is, until the next gizmo comes out. ;)

Best, Jim

Cor

19-Dec-2016, 04:52

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

19-Dec-2016, 13:27

...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

19-Dec-2016, 15:21

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

19-Dec-2016, 18:14

Here's a link to the BLB CFL bulbs for sale on Amazon.
http://www.amazon.com/Sunlite-SL220-BLB-Spiral-Blacklight/dp/B00V6POG12/ref=sr_1_1?s=hi&ie=UTF8&qid=1482196357&sr=1-1&keywords=sunlite+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

8-Apr-2017, 16:34

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

8-Apr-2017, 17:29

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

8-Apr-2017, 18:14

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

9-Apr-2017, 11:06

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

9-Apr-2017, 11:07

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

9-Apr-2017, 14:37

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.

john dean

9-Apr-2017, 15:24

I have to say that Sandy's clarification about the "good" leds and the cheaper roll out units makes sense to me.

By the way, my use of the phrase forgot more than most of the rest us know put together, was meant as a compliment not sarcasm. But whatever. But I'm not a novice either. I've been a very serious printmaker for 40 years, and although I haven't written any books or given workshops on 19th century processes, I did study for four years with Todd Walker, who was a major expert in the 1960s-1980's on all the alternative processes including woodbury type, carbro, gum, offset lithography, multicolor silkscreen and all the rest. - until he switched to computers after the mac was invented. I see leds as being the future for sure and I think it is great and exciting that people are beginning to consider them for photo printing. Last night we took a walk in our dark neighborhood and I pulled out my new micro led mag light that is tiny and uses only two AA batteries. That little thing has the illumination of my car headlight. And this is one of the cheap ones. Other units are far brighter. This is where lighting is going, fast. I'm going to look into the cost of the more durable led bulbs and if they are that much more expensive right now, I'll put the fluorescents in until the prices come down, then I'll convert to led. It wouldn't surprise me if the fluorescents are phased out in a couple of years the way this tech is taking hold. In the meantime I just want consistent exposures without any surprises. It sounds to me that Sandy has done more serious tests than anyone else who is doing this professionally. Platinum is too expensive to have to deal with inconsistent exposures from month to month. Thanks for all this great info. I knew there had to be someone who had done the tests.

sanking

9-Apr-2017, 16:48

John,

I often run into folks from the Atlanta area who praise your work so I know you are not a novice in terms of print making.

There is no question but that LED technology is an important development and sure to replace tubes in many cases. If you look now on ebay you will find many UV light boxes based on tubes that are imported from China. Most of these are made in a plant in Hangzhou. I met the owner of the plant last fall at a symposium at the Nanjing Institute of the Arts, which was equipped with several of his UV printers made with the higher quality LEDs. The units performed very well, about what I would have expected from a closely spaced bank of BL tubes. There is no doubt but that in a year or two all of the units coming from China will be equipped with the LEDs instead of tubes.

For a really high end LED light source, have a look at this one designed by Calvin Grier. Calvin is an American photographer based in Valencia, Spain, and an up and coming high end carbon printer. His unit is a point source type light designed to solve some of the adhesion problems in the highlights associated with carbon printing, but the design is potentially applicable to other forms of alternative printing. http://thewetprint.com/en/2016/09/16/exposure-unit-part-1-design/

BTW, LED tubes are already being manufactured as drop-in replacements for T8 fluorescent tubes. I have not located any UV LED tubes yet, but they are almost sure to come so this should allow for retrofit of existing banks of BL tubes if one desires. However, from a practical point of view a bank of closely spaced BL tubes is a highly efficient light source for alternative printing, though for best results diffuse light sources should really be used with a vacuum, especially for prints over about 8X10" in size.

Sandy

john dean

10-Apr-2017, 07:17

Thanks for that very useful info Sandy. I will look into those links.
You have done a lot more homework than I had realized.

Yea, there are a lot of considerations for the short term and the long term. Using a fixture that could be used for both led lights and fluorescents is a real possibility. I do wonder though if these will be available a couple of years down the road. But then everything is changing so fast. There may never be a permanent standard for light sources anymore. I just have to build a box that I can adapt to whatever is available.

One of the things I want to do is make large monochrome gum prints. I would like to have the ability to do 30x40s. So that means a big heavy unit in a studio with little space.

The four things I'm going to be considering are:

1. how well does the light source work

2. how long will the bulbs last before showing inconsistent exposures.

3. how big and heavy will the thing be

4. and last but not least, how can I keep mercury out of the land fill, the soil and the ground water. This a major consideration to me as it is poisoning the whole world, and a good reason to encourage the elimination of fluorescent tubes.

Lot to think about.

john

williaty

10-Apr-2017, 10:37

Regarding #4, UV-emitting LEDs are not total-lifecycle less polluting than linear fluorescent tubes. Semiconductor manufacturing is, sadly, a very Earth-hostile process. So each light source has a different way in which it harms the environment but neither are good for it.

john dean

10-Apr-2017, 14:48

williaty

10-Apr-2017, 17:19

Do these strip leds contain mercury? From what I've read, mercury is just about the most dangerous chemical used in electronics, especially crt monitors , etc. For one thing it causes neurological damage, cancer, and god knows what else.

Mercury is not even close to to the most toxic element used in electronics manufacturing. The rare earth elements take that title (which is what semiconductors use to dope silicon to get the various desirable properties like emitting light). From their mining runoff, to the smoke and fumes from refining, to the solvent effluent used to lithograph them onto circuit boards, it's a nasty, nasty process.

Not to mention the huge amount of oil consumed, and waste produced, in making the plastic parts of the LED tapes.

The sad truth is that every time we flip a switch on any of our light sources, something dies. Either from the manufacturing process or the energy used to light it up. There are simply no ecologically sound light sources out there once you get past burning wood.

Fr. Mark

11-Apr-2017, 19:53

Supposedly, anti coal mining activist and author Wendell Berry just goes to bed when it gets dark rather than use electric lights. Sometimes that doesn't sound so crazy.

denverjims

13-Apr-2017, 06:30

Supposedly, anti coal mining activist and author Wendell Berry just goes to bed when it gets dark rather than use electric lights. Sometimes that doesn't sound so crazy.

This whole thread seems to be turning dark...

Michael Kadillak

13-Apr-2017, 07:08

This whole thread seems to be turning dark...

Agree. We live in an imperfect world that contradicts the responsibility to the planet by a certain segment of the population that begins with a subset of unfounded conclusions. The analytical incapability of an intelligent society to properly assess all of the consequences toward a least damaging result is to me one of the most perplexing paradigms of todays culture. Surely we can ascertain the solution to the original objective of the post.

Paul Cunningham

4-May-2017, 08:12

Penance. Now that the waterproof vinyl-like material has yellowed, I'm peeling it off. Slow going. https://uploads.tapatalk-cdn.com/20170504/491ccca13e5dd52411477e009a52aba1.jpg

Paul Cunningham

5-May-2017, 18:09

Slow going.
It took more than a day to accomplish this, but I have some good news to report. My original print times, when the box was new, were about 240 seconds, not bad. My new print times are now about 100 seconds faster at 140 seconds total duration.

Tin Can

26-Mar-2019, 05:28

A shill post, but does point to the ascendancy of LED as very useful lighting.

This new company caught my attention last week.

Based in Wisconsin, they seem to be making some parts in USA, not clear on the LED source.

I expect Heiland competition soon.

https://lightpanel.us/innenausbau-pott/contact-us-2/about-us-2/

quote of deleted spam post removed

neil poulsen

27-Mar-2019, 07:36

This is really interesting.

I built my own unit years ago from 24" T12 UV fluorescent bulbs. I made it about 22" by about 25", so that it was oversized for 16x20. I checked around on the internet to get dimensional information. For example, the 1.25" diameter bulbs are spaced 1/4" apart. It turned our really nice, it was painted, and it had a drawer/shelf that rolled out and back in for the artwork. What was hilarious, is that I had a separate ballast and circuit for each bulb. Took me months to finish. Hundreds of connections. :)

That said, are you sure that your LEDs strips are spaced closely enough, in comparison to the distance to the artwork? (Rhetorical question.) I notice that the light sources are closer together along the strip, than side-by-side.

I'm wondering what the spectra distribution of LED lights are, compared to that of the earlier tubes? Are they bright enough? (Rhetorical question.)

As a comment, it will need to be longer and wider than your largest piece of art, to avoid the light fall-off at the borders of the light source.

It occurs to me that you could have easily purchased a brand new one, if you had sold your Arca. (Probably would have had some cash left over.) (Just kidding.)

Christopher Barrett

27-Mar-2019, 07:54

I expect Heiland competition soon.

I just emailed Jürgen to see if he's been thinking about it. My Nuarc works beautifully, but I'd love to go bigger.

Russ Fill

8-Nov-2019, 16:49

I was checking out Amazon the morning and found this (there are several similar) that powers the LED strips. This is still inexpensive and provides some features that my power packs do not so if you want to try building one of these, check this power supply out.

http://www.amazon.com/Lemonbest-Power-Transformer-Lighting-billboards/dp/B00NHDYMG0/ref=sr_1_72?s=hi&ie=UTF8&qid=1432303393&sr=1-72&keywords=led+power+supply
I have this same power supply that I use for my drone battery charger. Its great in that it does duo power input but it is kind of just a box with wires attached and there may be better options. Cheep yess but no features.

Paul Ron

8-Nov-2019, 17:14

ooops... uv. sorry

cant beat these tracing panels for only $24

https://www.amazon.com/NXENTC-Tracing-Artists-Sketching-Animation/dp/B07DYP468V/ref=sr_1_1_sspa?keywords=light+up+sketch+board&qid=1573258324&sr=8-1-spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUFYTEQzWjA3TTdRWEYmZW5jcnlwdGVkSWQ9QTAxODQ3ODQzSVhFQ0hEUDJZT1g4JmVuY3J5cHRlZEFkSWQ9QTA3MDgzNDMxRFkzMEdUQldNUDREJndpZGdldE5hbWU9c3BfYXRmJmFjdGlvbj1jbGlja1JlZGlyZWN0JmRvTm90TG9nQ2xpY2s9dHJ1ZQ==

they come in larger sizes too.

Paul Cunningham

8-Nov-2019, 18:05

I have this same power supply that I use for my drone battery charger. Its great in that it does duo power input but it is kind of just a box with wires attached and there may be better options. Cheep yess but no features.

I’ve been using this power supply in my UV box for the last several years. Works like a charm.

Sent from my iPhone using Tapatalk

Peter De Smidt

8-Nov-2019, 18:09

Randy, thanks for the tip. I emailed them asking about color characteristics such as CRI. Hopefully, I'll hear back. They might be a good source of product for all sorts of photographic purposes. I currently us a Chinese edge-lit panel in my 810 scanner, but it's be great to have a local source.

giranexp

9-Nov-2019, 00:55

Thank Eric. I have searched many tutorials, and this is the one I expected

Tin Can

9-Nov-2019, 16:27

Chicago June, https://www.globalshop.org/show/about/

Then Vegas

Randy, thanks for the tip. I emailed them asking about color characteristics such as CRI. Hopefully, I'll hear back. They might be a good source of product for all sorts of photographic purposes. I currently us a Chinese edge-lit panel in my 810 scanner, but it's be great to have a local source.

Jim Noel

10-Nov-2019, 14:26

I am coming into this discussion at a late date,and I am glad I didn't see it years ago and get tempted to build a new UV box with LED's..
About 1990 I built a box with 10 - BL bulbs. It has functioned well ever since and I have never replaced a bulb. There are 10 bulbs as close together as I could get them. A muffin fan cools the unit. My exposure times are about 2-3 times longer than the same print in the bright Southern Cal sun. I also have a NUArc, but i prefer the BL tubes. They are economical and do not heat up my darkroom as the NuArc would if I had it in the same 100sg.ft space.
My tubes are approximately 1.75" above my negatives.
Several years ago an experiment was performed by Judy Siegel publisher ofthe "The World Journal of Post Factory Photography". She was attempting to discover if the output of fluorescent tubes was evenly distributed. She blacked out every other tube in her UV box. Of course the exposure times were longer, but not doubled. There was no banding. Then she laid the printing package directly on the tubes. Still no banding. Why is this important?
Because it shows that fluorescent tubes are so diffuse they will expose our prints evenly with no banding even under unusual circumstances.
Until LED's can match the diffusion, UV output, long life-span and other qualities of BL tubes, I'll stay with what I have. AS I am now nearing 91, I don't expect to see it.

safe

19-Mar-2020, 01:23

This is an eye openner for me. Thanks for sharing

Neal

19-Mar-2020, 04:01

Amazing skills in DIY Perks's video......!!

Tin Can

19-Mar-2020, 04:44

From Tim Layton Blog

How I Updated My UV Fluorescent Printer For Platinum Printing With LED Lights (https://www.timlaytonfineart.com/blog/2020/3/how-i-updated-my-uv-printer-for-platinum-printing-with-led-lights)

Thank you Tim!

I ordered them 3/16/2020 and have used that brand LED white light in my shed for over a year.

Maybe I get them Saturday, as Amazon is now prioritizing food and medical...

PRJ

19-Mar-2020, 12:18

A little over a year ago I built a UV unit with three strings (90ft IIRC) of non coated strip LEDs I picked up off Amazon. It took a lot of soldering which was a pain, but the light is super bright. I get exposure times of around 90-120 seconds for Canon pigment negs on Cyanotype. I don't know if the UV will expose Platinum, but I have no interest in Platinum printing so iron based is just fine. I think the total cost was well under $150. If I went back and did it again, I'd probably make it slightly larger. IIRC the light is about 16x23ish in size. I put four computer fans in the end and they move quite a bit of air through it. I also made it pretty thin. All in all it was worth doing. I don't know why anyone would use FL bulbs anymore with LEDs that are so superior, at least for iron based stuff. With the strip lights you can make one any size you want. Want a ten foot one and you have the money? No problemo...

Jim Noel

19-Mar-2020, 15:17

I agree with Sandy. I built my box using BL's about 25 years ago. None have needed to be replaced. Printing times are fast enough. I also have a NuArc, which although faster by about 3/4 stop, rarely produces as nice a finished product, print, as my old fluorescents. I keep reading about LED's but in the end say, "Why bother? I'm Used to what I have and it serves me well."

Tin Can

19-Mar-2020, 15:21

Jim, I understand

I am starting from scratch at age 70

I have a NuArc Vacuum frame and pump that holds 16X20 tightly, if it had come with the lamp, things would be different

Jim Noel

19-Mar-2020, 15:55

ANother advantage in favor of fluorescent is the evenness of the output. without adding any kind of diffusion material the output is so diffused that even if a tube should happen to fail no banding would be evident in the print. In one issue of "The World Journal of Post FActory Photography" Judy Siegel reported on an experiment during which she blacked out every other Fluo tube with black tape. She laid her print directly on the bank of tubes and the resulting prints showed no banding.
It is hard to beat that kind of evenness of exposure.

Tin Can

19-Mar-2020, 15:59

Tim Layton also did that and agrees

The LED Tubes are coming regardless and now paid for

I will check and report

Tin Can

21-Mar-2020, 11:06

Amazon just delivered 3 packs of 4 Barrina UV LED Blacklight Bar, 9W 2ft, T5 Integrated Bulb

I will use 10 and keep 2 for spares, low heat, no fan planned at this time

Now in decontamination chamber for 24 hours

Drew Wiley

21-Mar-2020, 11:20

Jim, I'm VERY skeptical of those kinds of anecdotal tests, having constructed numerous fluoro tube lightboxes myself. Getting truly even diffusion is actually tricky. Maybe Bob S. will weigh in on this too. Of course, that's just an analogous case. Sandy K. has made some more detailed comparisons of UV tubes per se.

Tin Can

21-Mar-2020, 11:21

No need guys, we will do what we want

Insane advice with never a picture proof is worthless

Jim, I'm VERY skeptical of those kinds of anecdotal tests, having constructed numerous fluoro tube lightboxes myself. Getting truly even diffusion is actually tricky. Maybe Bob S. will weigh in on this too.

Drew Wiley

21-Mar-2020, 11:25

Did I just hear a can rattle somewhere? Don't tell me the possum is in the recycle bin again!

Tin Can

21-Mar-2020, 11:28

go away, this is DIY experimentation

if it doesn't work I will post images and not a wall of words

Did I just hear a can rattle somewhere? Don't tell me the possum is in the recycle bin again!

Bob Salomon

21-Mar-2020, 11:53

No need guys, we will do what we want

Insane advice with never a picture proof is worthless

With fl tubes the eve ness of illumination is also dependent on the distance the tubes are from the diffusion surface.
Kaiser slim boxes had to have a silver stripe, the length of the tube, to even it out as the top of the tube was so close to the diffuser you would get visible banding without that stripe.

Tin Can

21-Mar-2020, 11:56

Thanks Bob, that would be easy to implement

I also have Makrolon LD IF needed, it was designed for LED diffusion

With fl tubes the eve ness of illumination is also dependent on the distance the tubes are from the diffusion surface.
Kaiser slim boxes had to have a silver stripe, the length of the tube, to even it out as the top of the tube was so close to the diffuser you would get visible banding without that stripe.

Drew Wiley

21-Mar-2020, 12:11

LED diffusion? Think "rim lighting" rather than head-on diffusion. Don't worry,Tin Can, I'm just waiting for retouching station to warm up, and then I'll disappear.

Tin Can

21-Mar-2020, 12:17

Good news is always welcome

LED diffusion? Think "rim lighting" rather than head-on diffusion. Don't worry,Tin Can, I'm just waiting for retouching station to warm up, and then I'll disappear.

Mike in NY

5-Jan-2021, 19:55

Randy, I'm bumping this thread to ask if you put the LEDs to use, and what your experience has been.

Tin Can

6-Jan-2021, 04:20

I will not update this thread

Experiments continue

Out

Randy, I'm bumping this thread to ask if you put the LEDs to use, and what your experience has been.

Mike in NY

6-Jan-2021, 09:10

Uh - OK.

I guess there might be something amiss I'm not aware of; sorry if I've raised a pain point for anybody. I was just following an engaging thread as I finalize plans for my own UV box.

I've been in touch with Tim Layton this week about his use of newer LED technology (not the rubber coated strips originally mentioned when this thread was begun in 2016, but UV LED blacklight bars that are currently available and come ready to plug in and don't need any wiring knowledge or soldering). His experience has been very good, with no banding while using different solutions and papers, and he has significantly reduced his exposure times that make it easier to avoid platinum/palladium solutions drying out on the paper during long exposures. He used these bars to replace the original blacklight bulbs in his larger box. The cost includes two sets of four LED bars at $29 per set (total of $58) plus ~$20 for plywood. If you add the cost of some screws and corner brackets you can build a 20"x24" box for less than $100 in a few hours. In addition to my darkroom, I have a fully-equipped woodworking shop where I build furniture, so I can easily build a simple hinge-lidded box. But I never learned electrical wiring, so the ready-to-use "plug & play" aspect of these LED bars really appeals to me. (I can fix and even solder existing wiring, but I'm not experienced with creating wiring from scratch, daisy-chaining, and figuring out what ballasts to use).

BTW, I've read this thread in its entirety, and I don't doubt the observations from the members who advocate the use of bulbs, and I'm sure there are folks who could teach me wiring and ballast information in a matter of minutes. But for ease and minimal cost, I'm willing to use this alternative approach since I've seen the prints Tim has made and they speak for themselves, and convinced me this is a perfectly acceptable solution for my needs and budget.

williaty

6-Jan-2021, 09:11

I've been in touch with Tim Layton this week about his use of newer LED technology (not the rubber coated strips originally mentioned when this thread was begun in 2016, but UV LED blacklight bars that are currently available and come ready to plug in and don't need any wiring knowledge or soldering).

Do you have a link for an example of these bars? I haven't heard of them before.

Mike in NY

6-Jan-2021, 09:59

Fr. Mark

6-Jan-2021, 19:23

Thanks for resurrecting this. It is getting harder all the time to find "proper" fluorescent lights of any kind. I'll continue to use my 6 x 18" bug zapper bulbs until I can't, but it's good to know there are replacements out there. I've only ever used mine for Mike Ware's New Cyanotype, which I think he's updated again! Maybe someday I can get to Pt and C printing. Don't anyone hold their breath though.

Russ Fill

6-Jan-2021, 22:08

Sure... actually, Randy provided a link on his March 19th post in this thread. It's a link to Tim Layton's article about how he swapped out bulbs for bars in his existing light box. The article at this link will give you background information: https://www.timlaytonfineart.com/blog/2020/3/how-i-updated-my-uv-printer-for-platinum-printing-with-led-lights

This will link you to Amazon's listing for the bars that Tim used (Barrina UV LED Blacklight Bar, 9W 2ft, T5 Integrated Bulb): https://www.amazon.com/gp/product/B071NT6189/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

I just ordered the bulbs, and will post photos of the box as I build it, and will post dimensions and specs. Of course, the proof of the pudding will be the images I make with it, but Tim's prints are convincing, and he has told me that he has created over 100 prints with no banding or problems of any kind, using different papers and solutions. That information was important to me because he placed his bars farther apart (2.5 inches) than is typically recommended, but that's because the output is much stronger than conventional bulbs. He has also stated that he used 1x6 pine side boards to build his UV printer, so he estimates the distance between the LED lights and his contact printing frame to be about 5 inches.

Cheers.
I just ordered a set of 12 light. My plan is to place them like Tim did but make the light box an extra foot longer. That way Ill have a 36x24 box for a little large format or to be able to do a couple prints at the same time in different holders. Ill also try to post the finished product when I get it all sorted.
Thanks for the repost. Ive been holding off for just such a simple setup before building my light box. Finally technology has caught up with us... he he he....

Just a quick edit add. Doesn't it make sense to not get to short of an exposure time so you can adjust things more accurately? I mean the error on a 2 min exposure vs a 10 min exposure could be as little as a few seconds. I think Id rather have a little more wiggle room when working on a very large and time intensive print vs "crap thats a little too much"

koraks

7-Jan-2021, 01:23

Russ, concerning the timing accuracy, there are simple timer circuits to be had on ebay etc. that allow you to accurately and repeatably time exposures. My uv tubes have a 1-2 second startup time, which is insignificant. I regularly expose materials (mostly for pcb making) at 40-60 seconds, which works perfectly. Van dyke brown is around 150-200 seconds with my unit depending on the negative. No problems there either. It helps to have tubes with "instant" switch-on and that are suitable for quick on/off cycling. Bot all tubes fit those criteria.

malexand

7-Jan-2021, 08:18

I built a similar UV box as OP with flexible strip LEDs (not weatherproof) for salt printing and have been very happy with it. Not the brightest, but I haven't had any problems with banding or uneven prints - though I do subscribe to the baking suggestion of rotating your pan halfway through cooking... I'm sure I could beef it up for shorter exposure times, but just having a repeatable indoor UV source is worth more to me than short exposures.

For Timing I've got mine plugged into a surplus Gralab sweep timer - plenty accurate for this purpose.

Mike in NY

7-Jan-2021, 08:27

Just a quick edit add. Doesn't it make sense to not get to short of an exposure time so you can adjust things more accurately? I mean the error on a 2 min exposure vs a 10 min exposure could be as little as a few seconds. I think Id rather have a little more wiggle room when working on a very large and time intensive print vs "crap thats a little too much"

I think that's a good point to raise, Russ. I suppose this consideration needs to be balanced by the advantage Tim Layton has described as reducing the exposure time to avoid the solution drying out on the paper before the exposure is completed. All photography is a balancing act, right?

williaty

7-Jan-2021, 09:05

Printing on silver halide paper often has exposures in the 10 second range and we don't complain about a lack of accuracy and control, we just use a timer.

Carl J

7-Jan-2021, 11:28

Sure... actually, Randy provided a link on his March 19th post in this thread. It's a link to Tim Layton's article about how he swapped out bulbs for bars in his existing light box. The article at this link will give you background information: https://www.timlaytonfineart.com/blog/2020/3/how-i-updated-my-uv-printer-for-platinum-printing-with-led-lights

This will link you to Amazon's listing for the bars that Tim used (Barrina UV LED Blacklight Bar, 9W 2ft, T5 Integrated Bulb): https://www.amazon.com/gp/product/B071NT6189/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

I just ordered the bulbs, and will post photos of the box as I build it, and will post dimensions and specs. Of course, the proof of the pudding will be the images I make with it, but Tim's prints are convincing, and he has told me that he has created over 100 prints with no banding or problems of any kind, using different papers and solutions. That information was important to me because he placed his bars farther apart (2.5 inches) than is typically recommended, but that's because the output is much stronger than conventional bulbs. He has also stated that he used 1x6 pine side boards to build his UV printer, so he estimates the distance between the LED lights and his contact printing frame to be about 5 inches.

Cheers.

Hi Mike,

Please post the build pictures w/dimensions. I have 8 lights and am thinking 24x30 x 1/2". My build is on pause as my original length of 27" turned out to be too small with the way the connectors/wiring stick out from the end of the bulbs, so I'll go back with the larger dimensions. Maybe simple construction for many but some of us are klutzes (and I'd like to make a decent box). ;) I did see Tim Layton's video but some details are hard to see. Also curious what you recommend for hinges.

Thanks, and great thread all.

Tin Can

7-Jan-2021, 11:48

I made mine exactly 30" wide and used this exact hinge which required no cutting with 3/4 plywood

https://www.amazon.com/gp/product/B0002YS98Y/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

I drilled a big hole in the back low for my vacuum hose and power wires

I made the whole box from 3/4 ply I had, when not in use the top is useful work space

Hi Mike,

Please post the build pictures w/dimensions. I have 8 lights and am thinking 24x30 x 1/2". My build is on pause as my original length of 27" turned out to be too small with the way the connectors/wiring stick out from the end of the bulbs, so I'll go back with the larger dimensions. Maybe simple construction for many but some of us are klutzes (and I'd like to make a decent box). ;) I did see Tim Layton's video but some details are hard to see. Also curious what you recommend for hinges.

Thanks, and great thread all.

Carl J

8-Jan-2021, 01:04

Thanks, I appreciate the hinge recommendation. :)

Carl

Tin Can

8-Jan-2021, 07:03

You are very welcome!

I am trying to avoid unhelpful members...nearly impossible...

Thanks, I appreciate the hinge recommendation. :)

Carl

Mike in NY

8-Jan-2021, 07:29

I am trying to avoid unhelpful members...nearly impossible...

I can empathize with that. It's one of the reasons I have long absences from this site. Randy, I've enjoyed your posts and experimentation over the years, and am glad you weighed back in. Thank you.

Russ Fill

8-Jan-2021, 11:09

Can anyone say how tall or how far from the print surface the lights should be. I looked at the photos in the article and it seems about 6 to 7 inches but wondering if anyone has an idea on this. Im also thinking about lining the inside of the areas around the lights and sides with a reflective material like foil or something else like this to max out the reflectivity of the lights.
My biggest concern is that Ill get strips or bands or even individual dots from each light if I don't have the right heights of the light to the print.

Tin Can

8-Jan-2021, 11:30

I made my box 8" tall inside, with UV LED Barrina 2' tubes attached to the lid, facing down, so I can adjust and test optimal height

Testing is not complete, my max print goal is 16X20"

I placed my tubes 1" apart, using 10 of 12 bought, so I have spares, none failed yet

My dozen Barina 5K white 4' tubes are in Midwest unheated and uncooled big shed. running only when needed for 3 years

1 failed early, replaced from my extra stock

I now have one shed 5K Barrina running 24/7 since the Plague began, so far so good

I have compared noon summer Sun Midwest and my UV Box with a UVA meter

Not that different

but winter is a big diff

Runs on a common DR timer, bare wood in and out

I needed the 8" to allow my Vacuum frame room, but also use 2 smaller contact frames

Mike in NY

8-Jan-2021, 11:36

Russ, see previous post to answer your questions:

Tim's prints are convincing, and he has told me that he has created over 100 prints with no banding or problems of any kind, using different papers and solutions. That information was important to me because he placed his bars farther apart (2.5 inches) than is typically recommended, but that's because the output is much stronger than conventional bulbs. He has also stated that he used 1x6 pine side boards to build his UV printer, so he estimates the distance between the LED lights and his contact printing frame to be about 5 inches.

Tin Can

9-Jan-2021, 07:18

Tim Layton has just posted today an update on his LED UVA ALT PRINT design

No major changes, but he has changed his cover glass

https://www.timlaytonfineart.com/blog/2021/1/updates-to-my-led-uv-printer-for-making-platinum-prints

5 years ago I was going to make a 20 X 40" SG normal light contact printer from cheap heavy glass for usage with X-Ray 14X36" film

Then i moved to a secure location

Mike in NY

9-Jan-2021, 09:06

That's a great update that Tim made, and makes perfect since for Pt/Pd prints and other developing-out processes. I should consider the heavy glass sandwich as an alternative to my 11x14 print frame for Pt/Pd prints. A pressured printing frame would still be needed for printing-out processes so that the hinged half of it could be opened to check the print, but that's not needed for developing-out processes. Sometimes we get so accustomed to using a particular tool that we forget there are simpler alternatives, depending on the process.

Russ Fill

9-Jan-2021, 18:43

Thank you I missed that part about he 5 inches. which now makes sense that if you have a contact holder in the space I saw on the link that would lift or put the print about 5 inches or so from the lights.

malexand

10-Jan-2021, 06:19

I separated my LED strips by the same distance as between each LED on the strip - about 1cm if i recall. I'm sure a math person could tell me reasons why this is not the best, but it gives me a very even light. No spotting or banding that i can detect. They are about 3 inches above the glass of my print frame. Like baking cookies, i rotate the print 1/2 way through for even browning.

Mike in NY

16-Jan-2021, 12:48

I built my UV box this week with a useable interior surface area of 19" x 26". Here are the parts that I used, along with their dimensions and some assembly notes (everything other than the lights were purchased from Home Depot).

Lights: Barrina UV LED Blacklight Bar, 9W 2ft, T5 Integrated Bulbs (from Amazon at https://www.amazon.com/gp/product/B071NT6189/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1). I ordered two sets of four bars each, and ended up using six of them.

Base and lid of box: cut from two 2' x 4' sheets of smooth birch plywood

Four sides of box: cut from one 6' long 1"x8" premium pine board, clear of knots.

Hinge: Everbuilt brand continuous hinge 1.5" x 48" cut to length with my Dremel, but a hacksaw could also be used

Sheet metal screws for attaching hinge to lid: one package of pan head Phillips screws #10 x 2"

Machine screws and nuts for attaching hinge to box body: 12 screws with locking nuts were already on-hand in my shop

Wood screws for assembling sides and base to each other: 16 2" wood screws were already on-hand

Chain and 2 screw eyes for tilting lid back: hardware already on-hand

Electrical staples for attaching wires to lid: already on-hand

Power and hand tools used: table saw, miter saw, Dremel tool with metal cut-off wheel, drill and regular bits, countersink bit for wood screws, forstner bit for drilling out hole for wire to pass through, Phillips screw driver, socket wrench for tightening locking nuts, drywall square, ruler, pliers, sandpaper for smoothing board edges.

As stated above, the base of the box has a useable interior surface area of 19" x 26". The board dimensions are as follows:

Base: 27.5" x 20.5"
Lid : 29.5" x 21.5" (the lid extends 1" over the sides and front to make it easy to open it without adding handle hardware)
Sides: 19" x 7.5"
Front and back: 27.5" x 7.5"

Assembly Notes:

(1) The sides are attached to the "inside" area (i.e., to the flat surface) of the base, not to the "outside" 3/4" edges of the base. This means the distance between the base and lid within the box is 7.5".

(2) I placed 6 bulb bars 2.5" from one another, measured from side to side (NOT measured from center point to center point of the bars' placements). I placed my bulbs an inch closer to each other than Tim Layton did, but I also chose to make the sides of my box 2 inches higher than Tim's box. I will experiment to determine if there is any need to change the distance between the bulbs in case of any banding (which I don't expect based on Tim's placement of 3.5" between the bars). I can also place risers below my print frames to lessen their distance to the UV bulbs to adjust exposure times as I wish for different processes.

(3) The machine screws and locking nuts used to attach the lid hinge to the base of the box could be substituted with shallow 3/4" wood screws if desired (especially if the chain is installed to prevent the heavy lid from falling all the way backwards, potentially yanking the hinge away from the box), but I prefer the extra stability. Depending on where the furthest left and right holes on the hinge line up on the base of the box, you may need to use wood screws as you may not be able to use locking nuts at the far edges.

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Tin Can

16-Jan-2021, 14:02

Nice Mike

A member here is using that exact design to make and offer prints from 1k to 5K

Mike in NY

16-Jan-2021, 14:17

Wow, that's nice to know. I just sketched my plan for the box out on a sheet of paper, knowing what the maximum size of my prints would be (plus a little bit of wiggle room for my hands inside the box). But I'm comfortable designing stuff from scratch, although I paid careful attention to Tim's notes on the bulbs. Originally I was going to place a handle on the lid, but then I realized that wasn't necessary if I just made the lid a little wider than the body of the box - and it would be easier to manage anyway. The idea for the lid chain came after I made the box. At first I installed a moveable bracket that took a little fiddling with, but then I thought of the chain and switched to that.

The kallitypes I've made with the UV boxes at the Penumbra Foundation's Center for Alt Photography in NYC are pretty good. Now that I have my own UV box, I ordered my first batch of Platinum/Palladium chemicals from B&S this week. I'm eager to use them with 8x10 negs I shoot in camera, and larger digital negs I print from my Epson 3880. I just hope my P/P prints will be as acceptable as my woodworking skills.