Enlarger bulbs How long do they last?

[ray*j*gun]

I have never seen a discussion about this issue so here goes.

I have a Bessler Dichroric 67 (color) enlarger that I have been using for MANY years. In fact I bought it used over 30 years ago. The bulb is the original and its still working as of my session this morning.

So, 2 questions......do enlarger bulbs lose strength over time so that one gradually has less illumination even though it still responds to the switches?

And, if so where is a good place to get a bulb for such an old enlarger?

Thank you for your help!!

[Tim Gray]

They burn out suddenly. I would buy a couple spares now. They could get very hard to source in the future.

You could look at B&H or Freestyle for a replacement. Or you could find one on some internet bulk bulb store and save a couple bucks.

[sepiareverb]

I've found they last forever unless you have no spares on hand, then they last for only three exposures max.

[MartinP]

As you mention the enlarger has a colour head, that would probably be a quartz bulb? Just be sure to buy one designed for enlarger use, as you can then be sure the filament and reflector are in exactly the right position. It is might be possible to find a domestic bulb that physically fits, so far as the package is concerned, but which does not really give an even light of the expected colour temperature.

And sepiareverb is right - as soon as you really need the thing to last until the end of a print-run, Murphy's Law applies ! Buy three spares !

[sepiareverb]

Originally Posted by MartinP

Buy three spares !

And never change a bulb again.

[ChrisPlatt]

Having a good spare ensures that a burned-out bulb won't spoil a printing session.

Chris

[ray*j*gun]

Hmmmm thanks for the posts all........... so as long as my current bulb works it's providing the correct illumination? I was wondering if the strength could be reduced without my noticing and, as a result screwing up my printing?

Thanks again.

[Roger Hicks]

Dear Raymond,

Some of them do in fact dim over the years, but how could that screw up your printing? After all, you do a test strip; you give the print the exposure it needs; bulb brightness is not really all that relevant. By the same token, diffuser housings can discolour over the years, too, but again, you compensate for it more or less automatically via test strips (or enlarging exposure meter readings, if you do 'em).

Cheers,

R.

[rjbuzzclick]

I purchased bulbs for my Omega D2 (I print B&W only) at www.replacementlightbulbs.com.

[ChrisN]

This guy has a great site for finding obscure bulbs:

http://www.donsbulbs.com/cgi-bin/r/b.pl/elc|24v|250w~ansi.html

That's my bulb shown, for the CLS500 head on the Durst Laborator 1200. I felt very insecure until I had a few spares on hand!

[ray*j*gun]

I realize that there are lots of factors that can impact print quality.......I won't list them Roger....... but as I was trying to figure out what happened in my last print session it occured to me that I'm still using a VERY OLD bulb.....therefor I posted this thread. So from what I'm getting, there should be no issue with uniformity of light across the print at say 11x14? If that's the case then I will not worry about the "bulb fatigue lol.

LED's are a great idea..... I keep marine tanks (reef) and led fixtures have replaced metal halide lights in most applications. I would bet they would be great for enlargers.

Thanks all!! And thanks Chris for the link!!

[ray*j*gun]

And thank you rjbuzzclick for the link!

[Richard Ross]

I once changed a dead lamp in my LPL 7700 and immediately got a stop more light so yes, halogen lamps in particular do dim because the envelope becomes cloudy. That's unlikely to affect the uniformity of the illumination though given that the light bounces around the mixing box before hitting the diffuser.

Richard

[Chris101]

Originally Posted by ray*j*gun

... LED's are a great idea..... I keep marine tanks (reef) and led fixtures have replaced metal halide lights in most applications. I would bet they would be great for enlargers. ...

Maybe they would, or ...?? LEDs have narrow band spectra compared to a filtered white light. In substituting an LED for a filament based bulb you would need to match the output spectrum of the LED to the bandpass of the dichroic filter to the sensitivity of the dyes in the paper. If they all match then it's all good, but if not, then you will have difficulty when adjusting the color (for color work, or for multi-contrast b&w paper.) Also most LEDs are not yet as powerful as are quartz-halogen bulbs.