average life of a 1000 watt metal halide bulb?

[Shawn (EIP)]

I was just curious how long a 1000 watt metal halide bulb last? Mine is nearing 3 years old and I cant really tell if if it's dimmed any.

[Frog]

Lasting, like still working, and gradually losing intensity every time you use it are a little different. Even if a bulb may be rated at 3000 hours, hour #3000 is definitely different from hour #1. That's of course, why many use integrators which measure light rather than time and compensate for this deterioration.
Do you find any of your previous constants taking longer?
Of course, in three years, you may have changed coating techniques and emulsions a few times making it tougher to get an exact handle on it, but I'm guessing that a new bulb would not hurt..

[jsheridan]

6 to 12 months depending on use.

[JBLUE]

Next time you replace it time the fist exposure. Write it down on the unit. Like Frog said the light units will take longer as the bulb ages. When it gets too long and is slowing you down then its time to replace.

[Frog]

and save your old bulb for an emergency.

[Shawn (EIP)]

Lasting, like still working, and gradually losing intensity every time you use it are a little different. Even if a bulb may be rated at 3000 hours, hour #3000 is definitely different from hour #1. That's of course, why many use integrators which measure light rather than time and compensate for this deterioration.
Do you find any of your previous constants taking longer?
Of course, in three years, you may have changed coating techniques and emulsions a few times making it tougher to get an exact handle on it, but I'm guessing that a new bulb would not hurt..

yes, played around with many different emulsions

[ZooCity]

6 to 12 months depending on use.

Just to chap John's balls....we've been running ours for 2 years like a mule. 

This is not optimal for expo times and perfect dots and fine lines though. 

You know when these need swapped out.  The integrator starts running a unit for what seems like forever and the bulb will get all crudded up.  I'm literally just seeing if it will ever blow, had the new one ready to go for about a year now.   This may be the difference between a shuttered unit and a instant on/off.  We expose in one big run, once a day typically.  In fact I like to get at least half the weeks jobs shot in one go so this bulb is getting flipped on and off much less than in an instant strike unit. 

[Screened Gear]

There are a lot of variables. How many times you use it? How long your exposure time is. One of the big ones is, how many strikes does it have on it. Some units turn the light on when you start your exposure time. So every exposure is a strike on the bulb. These units are slower at exposing because the light is not at full power the whole time. They also burn a bulb out sooner. My Workhorse Photosharp has a 1000K bulb. It turns the light on when the unit is turned on. When you expose a screen the controller just opens and shuts a shutter that lets the light though. This way I can exposure hundreds of screens with only doing one strike on the bulb plus the bulb is at 100 percent power during the whole exposure. My exposure time for Aquasol HV blue with oem of 7 to 12 percent is about 18 seconds on 125 – 230 mesh. Less on 305’s.  I don’t do a ton of screens, I do 40 to 50 a week on average and my bulb has not lost enough power to get a new one after 2.5 years. To be honest I don't think it has changed at all. I know I am not measuring in light units so I am sure it is less over 2.5 years but I still get good burns, so it is good enough for me.

[RonH]

I will offer a couple of comments based on many years of working with Mercury Vapor and Metal Halide Lamps, both shuttered and instant start within the Screen and Litho industries.
 
Similar to standard bulbs we use around our home or office, not every lamp will last the same length of time.  You could have a lamp that gives you good service for 3 years and then have another that lasts 6-9 months.  I would say that if you were to average it out across the industry that the average is around a year.  The norm for these lamps is that the spectral output will change very little and rather slowly for most of its life and then as it nears the end of its life the spectral output will begin to fall off.  This is when you will normally begin to notice that it is taking longer to expose your screens.

The question often comes up about lamp life in shuttered vs. instant start units.  The main three things that effect lamp life are, the amount of time that it is on, the number of starts, and the environment that the lamp is in (operating temperature).   If a unit is exposing screens one behind the other most of the day, then the shuttered unit might be the best fit.   This way you would have only one lamp start and you would be using the lamp to expose, rather than sitting at idle much of the day.  Another application where the shuttered unit really shines is when your exposure times are very short, such as CTS generated screens.  I do believe that the instant start lamps are a better fit for the majority of shops and the difference in lamp life is effected more by the amount of use and the lamp environment.

Ron Hopkins
NuArc Sales Mgr.
M&R Sales and Service Co.

[Gilligan]

Not sure why I would eve reply after Ron but I will give my 2 cents.

In the stage lighting industry they use ARC bulbs in most of the intelligent fixtures.  They will strike the bulbs ONCE a night.  They will just leave them on from setup/preshow till the end of the show.  Striking the bulb hurts more than leaving it running for the extra few hours a night.

[Frog]

 I'm sure that I'm not alone, after yesterday's thread, in thanking Gilligan for not going in the direction of telling us about this friend of his and what he did with a light bulb!

[Gilligan]

And I'm the bad guy for clearing up the rumors of what had happened... yet you come in here and post this.  Tisk Tisk!