Hello all,

I need your help! I work at the Florida Museum of Natural History in the McGuire Center for Lepidoptera and Biodiversity. We are about to start taking images with UV light. But, I am having trouble finding the appropiate light fixture for EYE Color Arc MT70D. If you could point me in the right direction of a fixture, that would be fantastic! Thank you!!!

One option is if you can't find a fixture, you can just build one suitable for your application.

It is a Pulse Start Metal Halide lamp. This one gives Cool Daylight 6500K White light (colder than the usual "Cool White" 4000K), but very little UV

Metal Halide lamps are energy efficient lamps used for various lighting applications - Floodlights, Wall pack lights, High bay luminaires, Spotlights, Streetlights, and other applications. So you get to choose luminaire of one of those types

Metal Halide lamps need additional electrical components (ballast and ignitor) which are installed in the lantern. They have to match the lamp type and power rating, that is, each lantern is made to run a lamp of one specific type and power. You are looking for one for Pulse Start Metal Halide 70W, which is called M98 (it is 70W exactly, not "70W max" or "70W or higher"), and with Medium screw base socket

The lanterns are available for different voltages (120V / 208V / 240V / 277V) and some can work with more than one voltage, so choose the one that matches the power supply you have



When testing, note that Metal Halide lamps take time to heat up until they get to their proper color and brightness, and after switch off they take time to cool down until they will be able to light up again

Due to the nature of the higher density of the halide radiating elements in the discharge tube, there is a radiative-cooling effect on the plasma where UV light is actually lowered while in steady nominal operation. This is particularly true for daylight type rare-earth and ceramic-metal-halide lamps. The UV output can be made to be much higher when underdriving such lamps. Something you may want to consider to shoot in UV light.

Among the most UV radiating and readily accessible lamps are the uncoated clear Mercury-Vapor lamps. These can still be bought very cheaply on ebay. No need to run these with different watt ballasts, just have a bare bulb, and I would want to wear UV (sun)glasses for prolonged exposures of more than 5 minutes. Good luck slhuber.

Clear mercury vapour lamps aren't as dangerous with the UV, as glass blocks most of the UV radiation and lets only the long wave UV to pass.

First, there are ranges of UV :

UVA - low energy, right after purple in the visible light spectrum

UVB - high energy

UVC - very high energy

Discharge lamps made for general lighting have very little of all types of UV - because they dont generate much UVA in the 1st place, and Glass (of which the lamps is made) blocks the other ranges of UV. The quantity remaining is sufficient to discolor things exposed to the light of the lamp for years at close range, but not to do anything useful with the UV



UV is best achieved with Fluorescent lamps specifically made for UV :

UVA - Blacklight lamps (for stage effects)

UVB - Tanning lamps (for tanning beds)

UVC - Germicidal lamps (for air and water sterilization against germs)

Beware that UVB and UVC are dangerous for eyes and skin, use the correct precautions

Broken mercury lamps, can't be very dangerous with their short wave UV radiation, and there were documented cases in america about people that received eyes and skin burns from exposing to mercury lamps with broken outerbulbs.

You mean CAN be dangerous. And it indeed is dangerous, and warning against using a broken lamp is present in the lamp's use instructions

Not that I am disagreeing with anything said here, just adding.

If you shoot the spectra with a camera capable of recording UVA, or with any black-&-white film, you'll find that un-busted clear mercury lamps provide a healthy amount of light at the 365 nanometer emission complex. In the past I had recorded somewhere up to 330 nm with Kodak's Technical pan 2415 with an intact bulb

I will also attempt to insert a camera-spectrograph with some bare arc-tubes in a large (18" x 18") enclosure that has some of the air pumped out with a hand-pump. This will be a challenge since I would need to wire feed the socket+lamp and have a remotely triggered camera mounted up close to it. Problem might be in the choice of CMOS sensor capable  of recording into the UVB & UVA. I might have to go back to using film.

OK, do you think we should change our light source?

Here is a quotes from our proposal : "We will digitize the dorsal and ventral wing surfaces of 2000 pinned moth specimens using a Nikon DSLR D7100 with a UV-VIS-IR lens under UV/VIS light."

Thank you for your help!

If you want UV photography the best would be UV Fluorescent lamp, with or without an additional filter to remove visible light

 - UVA + some visible : "BL" Fluorescent as used for insect killers (safe to look at)

 - UVA alone : "BLB" Fluorescent as used for stage arts (safe to look at)

 - UVB + some visible : Tanning bed Fluorescent lamp (required eye protection & under longer exposure also skin protection)



The Metal Halide lamp puts out very little UV and lots of visible light, so the effect of UV would be impossible to see. This lamp is excellent for general lighing, not for UV applications

Thank you so much for your help!

Hi,

We have decided that we need to build an application. What ballast should be used and what base needs to be used? Sorry I do not know much about lights, so any help would be appreciated!

Sincerely,
Stacey

Have you decided what type of lamp you will be using? If you want to try to use the original EYE Color Arc lamp, you should be fine using any 70-watt metal halide ballast/fixture, like this one:

http://www.e-conolight.com/outdoor-lighting/floodlight/e-hp2m07qz.html

If you want to use a blacklight/UV fluorescent (which I would suggest if you're trying to get UV light), most are available in the same sizes/wattages as regular fluorescent tubes, so all you need is a standard fluorescent ballast/fixture rated for whatever size tube you end up using.

Now, if you want to use a clear mercury vapor lamp, you might have to do a bit more work as new mercury vapor ballasts and fixtures are no longer made. Fortunately, probe-start (NOT pulse-start) metal halide fixtures will also run mercury vapor lamps of the same wattage with no modifications. Now, probe start MH fixtures aren't made anymore either, but there are lots of them floating around, and the ballasts themselves are still made. The easiest way to get them is to look at places like Craigslist for the classic 400-watt industrial "high-bay" lights from warehouses and such (pictured below). They're pretty easy to find nowadays for not much money due to everyone moving to LED. Keep in mind, though, probe-start MH only exists for wattages 175W or higher. If you want a wattage below 175W, you can use pulse-start MH ballasts/fixtures with mercury vapor lamps, but a component called the ignitor must be disconnected first. Also, in this case, the equivalent wattages to go from MH to MV are NOT the same. If you want to go this route, I or someone else can offer more info on this.

High-bay light for reference:

Addition to nicksfan u can get EYE 400 watt MV. BLB
Lamp for UV application. For those high bay fixtures