If you work with incandescent stage lights, you’ve probably heard the rumor that you aren’t supposed to touch the halogen lamps that power many theatrical lighting fixtures.
That touching the lamp (or bulb) will shorten it’s life.
I was recently reminded of the “mystery” and scandal around this subject when I was working with a church on their lighting system, and asked the same question with a perplexed look.
Will Touching a Stage Lighting Lamp Shorten it’s Life?
Most often, yes.
In stage lighting, we see (2) main types of lamps that go into lights. There are par lamps, where the filament is encased in a very large glass shell, and then there are smaller lamps that go into ellipsoidal, source four pars, moving lights, and other similar units.
The second type of lamp, with names like HPL, BTR, BTN, FLK, and other lighting lamps all are similar in that they have a tungsten filament and halogen gas which allows them to glow very bright for a very long time. These and moving light discharge-type lamps are the ones that you don’t want to touch!
If you’ve ever been near an open lamp when it turns on, you know how hot and how bright the lamp gets. You almost have to shield your eyes!
These lamps have an amazing wattage to surface area ratio. This generates a lot of heat on the glass which must stay formed correctly to keep the halogen gas inside so the filament can shine. Compare one of these theatrical lamps to a household 60w bulb (remember those?), and you’ll see what I mean.
The exterior glass on theatrical lamps needs be able to cool as effectively as possible, and therefore needs to be clean of the oils of your hands.
When you change the lamp, you need to do so either by only touching the socket (which is impossible with some lamps), or use the foam or cardboard that the lamp is shipped in to hold the lamp while changing.
If you do touch the lamp, the oil super-heats a small spot on the lamp, and this is what causes the glass to discolor and blow out in a mangled pattern. If the lamp dies and is significantly discolored and warped in shape, then it most likely had oils on it that caused it to super heat.
A “normal” burnout of a lamp has glass that looks clear and unwarped, with a break in the filament that you can see visually.
So what if I touched the lamp before I changed it?
You may think that you have a throw away a lamp if you touched it, but that isn’t the truth either. To clean the lamp again, simply clean it with an Alcohol Prep Pad found at pretty much any grocery/drugstore or Amazon.
In fact, if you’ve worked with discharge moving lights, some moving light lamps require you to touch them in order to change the lamp, and they are shipped conveniently with an alcohol wipe.
And while you’re inside a light, make sure you don’t touch the reflector as it may be damaged by scratching it. Happy lighting!