UV light meters and UV light sources?

Jim Benson · Apr 13, 2015

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Note: I initially posted this in the exposure group, and somebody suggested that I post it here.

Im looking to start alternative processes, beginning with cyanotypes, and perhaps going beyond that.

My plan is to use a halogen work light as a UV source.

From what I understand, the output of these varies over the life of the lamp, and even to some extent of the duration of a printing session, which seems to call for a UV light meter.

Does anyone have a suggestion for a reliable light meter that is not too expensive? (a relative term, I know.)

Is it possible to save any significant money by trying to make a DIY version wthout sacrifgicing reliability?

And does anyone have any thoughtds as to whether here would be a better choice for a light source?

pschwart · Apr 13, 2015

check this out:
Dead Link Removed

Make sure you match the spectral output of your light source to the print process. I use fluorescent BL tubes for carbon transfer, palladium, and a few other processes -- instant on, cool running, and the bulbs last forever

michael9793 · Jul 14, 2015

I went another direction and hope this will help some with the exposure units out there. Most are very expensive and heavy. They are hand made and really nice. But I wanted a vacuum tray and I did not want the unit to break my bank account. So what I have gone to is a Silk screen exposure unit. It is called X_Vactor. This was purchased from silkscreensupplies.com. the base is the lights and the top is a rubber matt that vacuums down on to your work. It has 8 UV lamps, 2 safelamps (Yellow). it is 30x36 in size. the vacuum pump is attached to the side of the unit. I'm sure they have other units smaller and larger. the case is out of aluminum with a timer. I have done platinum,carbon, and 4 color gum prints, using a registration strip to keep it all in registration. Check it out. you may find that this is what your looking for.

Ian Leake · Jul 15, 2015

I suspect that you’re looking for a solution to a problem that doesn’t really exist. Fabulous cyanotypes have been made over the last 150 years or so without anyone having a UV light meter. If you’re using a split back printing frame then you can learn to estimate exposure by carefully opening one side and looking at the print.

I don’t know if a halogen work lamp is suitable for cyanotypes. They chuck out a lot of light but I’m not sure how much UV is in there. And don’t they get very hot? The sun works fine. Or a bank of UV (black light) fluorescent tubes works very well and is fairly easy to make. And if you’re making small prints then an off the shelf facial tanning unit is perfect.

michael9793 · Jul 16, 2015

michael9793 said:
I went another direction and hope this will help some with the exposure units out there. Most are very expensive and heavy. They are hand made and really nice. But I wanted a vacuum tray and I did not want the unit to break my bank account. So what I have gone to is a Silk screen exposure unit. It is called X_Vactor. This was purchased from silkscreensupplies.com. the base is the lights and the top is a rubber mat that vacuums down on to your work. It has 8 UV lamps, 2 safe lamps (Yellow). it is 30x36 in size. the vacuum pump is attached to the side of the unit. I'm sure they have other units smaller and larger. the case is out of aluminum with a timer. I have done platinum,carbon, and 4 color gum prints, using a registration strip to keep it all in registration. Check it out. you may find that this is what your looking for.

I want to make it clear that the unit I bought is not cheap. It is $1200.00 but it is 30x36 inches in size. the biggest one I had seen made for platinum was 20x24 and they were 1000.00 w/o a vacuum frame. So you add the extra size and vacuum frame 200.00 dollars is much cheaper than the others. But most don't try to do 20x24 inch or larger Platinum or 4 color gum prints.

RalphLambrecht · Jul 17, 2015

You do't need a UVlightmeter just do a quick test strip to determine the correct exposure time.Don't take technology beyond practibility!

cliveh · Jul 17, 2015

I would also suggest you don't need a UV light meter, but just time to experiment. Exposure time to UV is not critical for alternative process techniques.

silvermazda · Jul 18, 2015

I hope you got the nice summer sun I got here in the SF Bay. And sorry, but I started last month with a reptile UV bulb 24 inch fluorescent that's supposed to have 10% UVB and 30%UVA and at a distance of 15inches it took 3hrs to get "baby blue" tones. I used the standard recipe on alternative photography dot net.

Truth is: -the sun produces 100W per square foot of light. Not sure if it's also 100W/s. But there's no way my 20W fluorescent putting out 30% or 7w of UV light was going to have any damn worth!! You're better off with a 500W incandescent. Those only put out 5% visible light, tons and tons of IR and some UV. But because of the Energy department, those aren't sold anymore in regular stores. SO try photographic flood lights. GOOD luck You're going to need it. I have given up and am now using the sun. 10mins vs an hour.

pschwart · Jul 19, 2015

RalphLambrecht said:
You do't need a UVlightmeter just do a quick test strip to determine the correct exposure time.Don't take technology beyond practibility!

Just to clarify: you don't need a light meter if you use artificial light source with consistent output. The sun is hugely variable in many locales. Unless you are willing to always print by inspection and don't care about print matching, you will want a UV measuring device that measures the the exposure regardless of source variability. In San Francisco, sun printing without one of these is an exercise in frustration, wasting time and materials. If you are really serious about alt printing, an artificial light source is the way to go.

sfaber17 · Jul 19, 2015

silvermazda said:
Truth is: -the sun produces 100W per square foot of light. Not sure if it's also 100W/s. But there's no way my 20W fluorescent putting out 30% or 7w of UV light was going to have any damn worth!! You're better off with a 500W incandescent.

I have also used the sun and tend to agree, however if the sun isn't shining the next best thing is an old GE sunlamp 275W flood lamp style. It says on the box that it puts out several times more UV than the sun close to the lamp. I don't know if you can still get them. Mine is from the 60s. I think they are a mercury vapor lamp ballasted with a tungsten filament lamp in series.

michael9793 · Jul 20, 2015

cliveh said:
I would also suggest you don't need a UV light meter, but just time to experiment. Exposure time to UV is not critical for alternative process techniques.

Okay I agreed with you, BUT after I recieved the meter and and started using it on my $1200 light box I finally got it. at 63 it sometimes is hard to get it, I set it up and just turned on the lights and watched the meter for about a minute. Lo and behold the power of the lights started to increase. This increase in a min was 20%. Okay think how much 20% change in light is. these lights are now stable. Just turning on the light doesnt mean your getting the same amount of light , so your guessing. and not having one more obsticle to make a print is fine with me.
NOW for the meter. it is well built and comes in a very nice case which is water proof. the sensor is very thin and will fit through the frame of my light box. Oh I got the one with the extended sensor so I did not have to use the senor box to get my reading. no mater how long your exposure is or how short you change it to it will always be calculated for the change in the intensity of your light. thank you for making the meter. wish i got it years ago.

michael9793 · Jul 21, 2015

silvermazda said:
I hope you got the nice summer sun I got here in the SF Bay. And sorry, but I started last month with a reptile UV bulb 24 inch fluorescent that's supposed to have 10% UVB and 30%UVA and at a distance of 15inches it took 3hrs to get "baby blue" tones. I used the standard recipe on alternative photography dot net.

Truth is: -the sun produces 100W per square foot of light. Not sure if it's also 100W/s. But there's no way my 20W fluorescent putting out 30% or 7w of UV light was going to have any damn worth!! You're better off with a 500W incandescent. Those only put out 5% visible light, tons and tons of IR and some UV. But because of the Energy department, those aren't sold anymore in regular stores. SO try photographic flood lights. GOOD luck You're going to need it. I have given up and am now using the sun. 10mins vs an hour.

Let me get this straight. you are using one bulb to expose your prints. well most light boxes use anywhere from 6-8 bulbs. One light bulb is not going to do it. My light box uses 6 bulbs and my average exposure is 2.5 mins. Try building or buying a UV box. you will find that your light will be so much more happier.

Vaughn · Jul 21, 2015

I use a self-ballasted 750W mercury vapor lamp. About 18" from the contact printing frame -- with a fan to keep the glass of the printing frame cool.

http://www.elightbulbs.com/catalog_product.cfm?source=NexTagCSE&prod=IL68731

Tempted to get a UV meter as I give workshops and often have to deal with different types of lights.

Ian Leake · Jul 21, 2015

Vaughn said:
I use a self-ballasted 750W mercury vapor lamp. About 18" from the contact printing frame -- with a fan to keep the glass of the printing frame cool.

How long do you find these bulbs last? I've steered clear of these because of a fear that continually switching them on and off will blow the bulbs. Is that unfounded?

Vaughn · Jul 21, 2015

I have used them for a several years -- no idea on the hours -- so far so good. I keep them on for the entire printing session (about 10 hours or so). That is what they are designed to work. One does not want to switch them on and off -- they take a while to re-start, and I get consistent light output once they are warmed up (10 to 15 minutes). Generally, I pull a print from under a light and then toss another under right away (either the same neg or a different one). I will usually have two lights going. My exposure times are 30min to 2 hours with camera negatives -- and my students' time with inkjet negs are closer to 10 to 15 minutes.

According to the specs: About 20% of the bulbs will burn out after 8000 hours, going to 50% burning out after 16000 hours of operation. There is, on average, a 20% drop in lumens (but UV?) after 8000 hours, and 30% drop after 16000 hours. Not too bad.

Ian Leake · Jul 21, 2015

Thanks Vaughn.

monst · Jul 22, 2015

i expose my cyanotypes with a cheap used face tanning unit

Jim Noel · Jul 22, 2015

silvermazda said:
I hope you got the nice summer sun I got here in the SF Bay. And sorry, but I started last month with a reptile UV bulb 24 inch fluorescent that's supposed to have 10% UVB and 30%UVA and at a distance of 15inches it took 3hrs to get "baby blue" tones. I used the standard recipe on alternative photography dot net.

Truth is: -the sun produces 100W per square foot of light. Not sure if it's also 100W/s. But there's no way my 20W fluorescent putting out 30% or 7w of UV light was going to have any damn worth!! You're better off with a 500W incandescent. Those only put out 5% visible light, tons and tons of IR and some UV. But because of the Energy department, those aren't sold anymore in regular stores. SO try photographic flood lights. GOOD luck You're going to need it. I have given up and am now using the sun. 10mins vs an hour.

Your tube is to far away.
I have two light sources. The one using fluorescent UV tubes is 2 inches above the printing frame. It has served me well for over 20 years.

Vaughn · Jul 22, 2015

Jim Noel said:
Your tube is to far away.
I have two light sources. The one using fluorescent UV tubes is 2 inches above the printing frame. It has served me well for over 20 years.

You could have them 4 to 6 inches a way without a noticeable change in exposure time -- but 15 inches is quite a distance.

silvermazda · Jul 26, 2015

true, but my exposure area was 3- 8x10s in a row. And it was one tube. Evenness was the key. plus keeping it all even. I got uneven exposure under 4 inches.

silvermazda · Jul 26, 2015

As for my current/next solution I thought about mercury/metal halide lamps. Then I remembered that with in 1hr I exposed one well which had a paper negative. Yes standard office paper, yes in sunlight it takes an hour. So if I remembered right..

5-45W Full spectrum cfl's for fluorescent studio lights (studio pro brand on amazon) has decent UV output. Very surprising.
225Watts at 4 inches or less.

michael9793 · Aug 3, 2015

I guess if your doing just 5x7 or 8x10 prints you can get away with one light or two. but 6-8 BL's would make your life so much easier. there are so many places on the internet on how to build these things, and they are not that hard.
I print palladium prints that are 16x20 size so I need a large printer. mine has 8 UV tubes and two safe light tubes. exposures run around 2mins 30 sec on the average. Of course 5x7 or 16x20, the exposure is the same because it is contact printed at the same distants

wandrian · Sep 10, 2015

Wondering if this is a simple MH / HPS 1000w setup: http://www.amazon.com/dp/B00FICG2MK?psc=1 . Bulbs look to be in the right temp range. I used to use a box of 12 super actinic fluorescent bulbs for printing. That worked well, but the box never made the cross country move with me and I do not have the tools to build a new one. So now I am looking for something super simple to set up, and relatively cheap.

GregW · Sep 10, 2015

I just set one of these up for salt printing, etc. Haven't used it yet. Fingers crossed!

wandrian · Sep 11, 2015

GregW said:
I just set one of these up for salt printing, etc. Haven't used it yet. Fingers crossed!

Would be interested to hear what you think when you get it running. Did you get the 1000w or 750w?

UV light meters and UV light sources?

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