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Compact Fluorescent Lamp UV Emission

UV Lighting Filters White Balance
19 replies to this topic

#1 Stefano

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Posted 17 May 2020 - 20:24

I tried to photograph a 23 W "cool daylight" 6500 K CFL bulb, as I wanted to see how much UV they emit. I knew they do emit some, but I wasn't expecting this.

Camera: Full spectrum Panasonic DMC-F3, filter: ZWB2 (2 mm) + chinese BG39 (2 mm).

F-stop: f/2.8, ISO 400, 1/8 s exposure.
Attached Image: P1000725.JPG

F-stop: f/3.1, ISO 400, 1/8 s exposure.
Attached Image: P1000759.JPG

Since I already had a UV white balance set in-camera, that's how the bulb appeared on the camera screen. I thought for a moment I forgot the UV-pass filter, since it looked like a visible light image, but the filter was in place. That was UV (and quite a bit of it).

Polycarbonate goggles (blue) and 2 mm ZWB2 (yellow).

F-stop: f/3.1, ISO 1600, 1/8 s exposure.
Attached Image: P1000746.JPG

Are we sure this things are healthy to look at? An LED bulb emits basically no UV light, and the little they emit is above 380 nm. Here I probably have the 365.4 nm I-line as well as some "blue UV" (I don't think I am seeing the 404.7 nm H-line).

#2 dabateman

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Posted 18 May 2020 - 04:11

Oh no definitive not healthy for you or to look at. My mother worked at a senior center for couple years prior to the whole COVID thing, and fluorescent lights always caused a problem with seniors. She would give them an incandescent light bulb, and they would be much better. Even the hum from them is bad for you.
The reason I first moved my imaging down to the basement was to use the fluorescent grow lights that were left in the house from the previous people. They output enough UV for imaging with what I had before I knew about better lenses.
So a BaaderU filter and a pentacon lens or the Olympus 35mm macro would easily work with a regular mercury compact fluorescent bulb.


#3 enricosavazzi

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Posted 18 May 2020 - 20:32

One useful thing to know is that the amount of UV emitted by fluorescent tubes (especially old-fashioned big straight ones rather than CFLs) increases as the tubes age. I accidentally took UV pictures of the mouth of a highway tunnel in NY that show fluorescent tubes as UV-bright as the sunlight outside the tunnel. I guess those fluorescent tubes are on 24 hours a day and are replaced only when they completely stop working.
-- Enrico Savazzi

#4 Andrea B.

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Posted 19 May 2020 - 17:31

I'm surprised by how much UV those curly lights emit!

All this a good reminder to me to continue replacement of the fluorescent tubes in our garage ceiling. We are going to use LED tubes instead. And fluorescent tubes seem to always have a pesky flicker which annoys my eyes.

I think we should move this topic to the documentary Forensic area, yes? It is a really good example for that section.
Andrea G. Blum
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#5 Stefano

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Posted 19 May 2020 - 19:56

View PostAndrea B., on 19 May 2020 - 17:31, said:

I think we should move this topic to the documentary Forensic area, yes? It is a really good example for that section.
Again, no problem here.

#6 DaveO

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Posted 29 May 2020 - 01:50

Here's an interesting link about UV light and CFLs

https://www.energyra...ting-and-health

#7 Andrea B.

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Posted 29 May 2020 - 23:22

That is very thorough. I read the part about migraines with interest as I've had that kind of headache a few too many times. I really did *not* like working under fluorescent lighting during my techie days and had some special glasses made up which helped.

These days at home we have only incandescent or LED lighting. All fluorescents, such as the garage work lights and laundry room lights, have been replaced with LED tubes or LED or incandescent bulbs.
Andrea G. Blum
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#8 Stefano

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Posted 29 May 2020 - 23:28

Low wattage incandescent bulbs (like 25 W) can also flicker a bit. The filament is so responsive that, even if heated up 100 times per second (in Italy we have 50 Hz mains) it cools down a bit in the "off" times. I connected a speaker to a little solar panel (the one I used to emit infrared light in another experiment), and heard a 100 Hz tone putting the solar panel near a 25 W incandescent bulb.

Higher wattages (like 60 W or 100 W) flicker less, since the filament has more thermal mass.

#9 Cadmium

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Posted 29 May 2020 - 23:58

Your goggles transmit some UV.
The same experiment with my UV glasses shows absolute black.
Uvex Ultra-Spec 2000 Safety Glasses - Amber
https://www.fullsour...om/uvex-s0290x/
Very inexpensive.

#10 Stefano

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Posted 30 May 2020 - 00:05

View PostCadmium, on 29 May 2020 - 23:58, said:

Your goggles transmit some UV.
The same experiment with my UV glasses shows absolute black.
Uvex Ultra-Spec 2000 Safety Glasses - Amber
https://www.fullsour...om/uvex-s0290x/
Very inexpensive.
Thanks Steve, but it seems they can't ship internationally. If you find a seller that can ship in Italy, let me know.

#11 Cadmium

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Posted 30 May 2020 - 00:30

According to their web page, they do ship international. See the bottom paragraph.
Did they tell you something different?
https://www.fullsour...er-Information/

Google: "Uvex Ultra-Spec 2000 Safety Glasses Amber".
I am sure you can find some place that will ship to you.

Edited by Cadmium, 30 May 2020 - 00:36.


#12 Stefano

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Posted 30 May 2020 - 01:00

I will search for them.

#13 Cadmium

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Posted 30 May 2020 - 02:13

Safety first. Those are leaky UV eye wear. Keep those young eyes young.

Edited by Cadmium, 30 May 2020 - 02:13.


#14 Cadmium

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Posted 30 May 2020 - 06:24

Same tests here, few variables, but intended to be close to the same.

Nikon D7000 UV/IR, UV-Nikkor, Baader U on lens.
Same white balance for all shots.
I could not find my standard clear polycarbonate shop glasses, so I grabbed the closest thing I had, a Pelican Micro Case clear lid.

Attached Image: Two_Bulbs_UV_1080.jpg

Attached Image: Two_Bulbs_UV_Uvex_Amber_1080.jpg

Attached Image: Two_Bulbs_UV_Polycarbonate_1080.jpg

I am surprised at the amount of UV emitted from these 2700K house bulbs, although the brightness is less.
I would not want to be using the polycarbonate for eye protection.

#15 Andy Perrin

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Posted 30 May 2020 - 14:31

I own those UVEX glasses. Happy to see they work ok.

#16 Cadmium

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Posted 30 May 2020 - 18:30

Andy, Do you have the Amber or Orange? I have both, but I always use the Amber ones.
It probably doesn't matter much, but the Orange ones I have leak a little UV around 380nm or so, very slight, but a difference from the Amber ones.
I sent my first pair of Orange ones to JCDowdy for testing. I got another pair of the Orange, and they tested the same.
So I have always just used the Amber ones.
You can get them on eBay, but they are more than 3 times the price of Full Source.
By the way, I didn't find my clear shop glasses and goggles, and they both test to be blue not black like the UVEX.
One of the nice things for me is the UVEX fit on over my glasses very easily.

#17 Andy Perrin

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Posted 30 May 2020 - 20:32

Amber - I bought them after you mentioned the orange leak.

#18 dabateman

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Posted 30 May 2020 - 22:02

This will not affect many here but I find the orange are actually better at blocking the deeper UVc 254nm region. I wear them when working with the deeper lights. Sometimes wear both the Amber and Orange.

For most people though the Amber are probably best.

#19 Cadmium

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Posted 31 May 2020 - 00:18

That is an interesting question. Given all the people selling and buying those UVC hand held sterilizers (and such) to zap the virus,
the question has come up if the UV glasses will protect against UVC as well as they do against UVA.
Of course I can test UVA, but I don't have a good way to test for UVC.
Yes, you could wear both.
I have heard some glasses/goggles say they block "UVC" on them. I actually have not read the specifications for the Amber and Orange to see if they say anything about UVC.

This link says they are good from 220nm up, but I would like to see that in specifications somewhere.
https://www.cureuv.c...ASAAEgIAPPD_BwE

Edited by Cadmium, 31 May 2020 - 00:37.


#20 Cadmium

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Posted 01 June 2020 - 12:41

Stefano, You are correct.
Although the Full Source website talks about international shipping, they send me an email saying they don't ship internationally, unless you use a fright forwarder...
So, nope, sorry to say. But they can be found other places, just maybe not as inexpensively.