A Step Closer to UVA

[colinbm]

A Step Closer to UVA.

I found this QTH lamp at Newport's......

https://www.newport.com/p/6333

DHL got it to me in a few days earlier then expected.

So what have I got, Quartz Tungsten Halogen 12v 100w.

 

First we have the lamps spectrum.....not as steep as the graph they show.....

Second is with a BaaderUV filter, it covers the UVA spectrum with a peak at 370nm.

Conclusion, it is useful with exposure times of around 1 second, but I think I want more.....?

 

 

[Stefano]

If it runs at 12 V and has an expected lifetime of 2000 hours, you can run it at at least 18 V, but it probably won't last more than 10-15 hours.

[colinbm]

Thanks Stefano

I need to find a nice lamp holder for it....?

I have a ceramic connector.

[ulf]

STEFANO, where did you find the expected lifetime of 2000 hours? It is wrong!

 

According to the data in the link the expected life time is 50h. At 18V it will die very quickly.

It is a rather expensive lamp to kill that way.

 

Most of these type of lamps need some fan cooling to survive well.

This is normal for lamps in slide projectors and similar light sources.

 

The mounting direction and lack of strong vibrations is also important for good survival.

They shall be stationary when on.

 

The relative amount of UV compared to VIS depends on colour temperature.

Then a higher power rating increase the total output of light.

 

If you want to find more alternatives, look in the german lamp family data-sheet I posted.

Most of the ones with high colour temperature have a short lifespan, like 50h.

 

If you find something promising search on eBay. Then you might find lamps to better prices.

 

I searched for Osram HLX and found this:

https://www.ebay.com/itm/OSRAM-64633-HLX-150W-15V-G6-35-54250-BRJ-XENOPHOT-3450K-5600lm-50h-Halogen-lamp/362619700740

Also 50h, but higher power and colour temperature. Ten of them not so expensive.

[Stefano]

STEFANO, where did you find the expected lifetime of 2000 hours? It id wrong!

I didn't find it, I didn't even search for it. I said that IF that was the rated lifetime (it is usually 2000 h), you could overpower it. But if the expected lifetime is 50 h, it is better to keep it at 12 V. Some lamps are rated for as little as 15 h.

[Stefano]

I usually play with car headlights and run them at 18-20 V. They don't last long, but they produce a whiter light with more UV.

[ulf]

I didn't find it, I didn't even search for it. I said that IF that was the rated lifetime (it is usually 2000 h), you could overpower it. But if the expected lifetime is 50 h, it is better to keep it at 12 V. Some lamps are rated for as little as 15 h.

OK, I see that now when rereading the text. Missed it. Sorry.

 

I do the same, but only for short periods without destroying the lamp.

For a very brief moment I did run my 6V 20W lamp on ca 9V to see how much more UV I got. As it is a 50h lamp i quickly shut it off.

[dabateman]

Colin,

Can't you buy a black fluorescent bulb? Like a blb compact fluorescent black light?

The BLB, has the filter for mostly UVA off the source mercury bulb. They have the 335nm line as well and I like these with my 340bp10 filter.

The are nearly equal intensity at the 365nm line to a 365nm led bulb, which are, more expensive. But are broader spectrum for UVA and sometimes dip into the 405 and 435nm.

[colinbm]

Obviously I am looking for something that doesn't exist....?

I am looking for a nice continuous spectrum in UVA.

The BLB & all mercury vapour lamps have a strong spike at 365nm. But none of these have enough out-put for fast photography, like 250/second....

I was hoping that the Newport QTH lamp would be more useful, but a few together maybe the answer ?

The Newport was disappointing when you compare their spectrum with mine.....

 

 

[ulf]

The difference in the diagrams is due to that Newport is using a log scale while yours is linear.

Both can be correct.

 

It is just the expectation that where not realistic.

It is difficult to get much UV-light.

[colinbm]

Thanks Ulf,

" It is difficult to get much UV-light. "

I am realising that fast.....