UV Light Question - Useful Life

I'm not sure if this is the correct topic category for this question, but here goes.

Do the bulbs in UV lights deteriorate over time, requiring them to be replaced periodically. If so, what would the useful life typically be?

I use a Raytech LS-4 unit with filters for short and long wavelengths.

Frank.

Yes, they do. The life depends on the bulb used, and if you can still find the bulb number ( imprinted on the glass tube ) you can look up the manufacturer's specifications.
As a real life example of a bulb going bad - go to any large office building or warehouse with rows and rows of fluorescent lights. You will see a very noticeable difference not only in light output but also in color. This is due to the age of the bulb. The same is true for Cathode Ray Tubes and to a lesser extend for solid state displays. Nothing lasts forever.

Peter

ac uv bulbs are more efficient. I explore batches under desklamp ...
https://www.ebay.ca/sch/Light-Bulbs...045573.m1684

4watt bulbs are useless

Rated Average Lamp Life is typically said to be between 6000 and 8000 hours but much like 'acid free paper' this is a bunch of marketing fluff. Bulb life is greatly shortened by power cycles (turning on and off) and even physical events like impacts. (This is why you want to buy your lights and bulbs direct from manufacturers.) So consumers are left pretty much left to figure out if their lamps are actually working well or not.
If your lamp is over a year or two old and you are having difficulty, it would be prudent to replace the bulb.
Don

Well my LS-4 has been "bouncing around" in my work area for the past 6 or 7 years (since the last bulb replacement). Although I am sure it has nowhere near 5000 hours under its belt, I have lately felt that it really doesn't illuminate the subject or the mind as it should. In particular, it is hard, even on a 6-panel booklet pane, to get an even fluorescent exposure. Perhaps bicolor is correct in saying that 4 watts just doesn't cut it. RayTech also has a 7 watt model. Do you think this would be a major improvement? I looked at the link to the ebay search you provided but that seemed mainly for sterilization and other non-philatelic uses. I would like to have a lamp which can work on both short and longwave ranges individually and at the same time.

I do not really know why you ask if 7 watt is better than 4 watt. Take a 40 watt lightbulb and see the difference with a 60 watt one. Of course it is better. I use a 4 watt battery job for road work, but if I really want to look at tagging I use an 11 watt lamp

Peter

Peter:

You are right, of course, and perhaps this was a bad choice of words on my part. Perhaps I should have asked whether a 7 watt unit would provide a sufficient improvement, given my needs which relate to papers and coatings rather than tagging.

Frank.