Indoor UV Portrait Using UV Lamps

[The Skin Doc]

I am a Dermatologist that offers free UV assessments of my patient's faces. I've set up a makeshift photo studio. I literally just take a snap shot using both UV and Visible Light.

 

Canon 5D Mark III UV Converted

ISO - 3200 Aperture - 4.0 SS - 60

X4 104W UV Bulbs

[OlDoinyo]

I have heard mixed things about the significance of UV-apparent skin spots. Some have claimed that they are an index of skin damage whereas others seem to ridicule the idea. What is your personal take on this?

[Andy Perrin]

I would like to know if this goes beyond a way to sell extra dermatologist visits also...considering that UV exposure from the flash lamp certainly is not good for skin.

 

ETA: Oops, yes it is lamps, and it even says so in the title of the post. My error. But I still have questions about how safe it all is, and whether there is really any benefit...

[Cadmium]

I don't think he is using a flash. He says 4x 104W UV bulbs.

So that leaves a lot to the imagination. Do the bulbs emit any UV below UVA?

If it is just UVA, and not prolonged exposure, then I wouldn't think it would be that bad for the skin.

I have not tried this, but let's say I illuminate my hand with a common 'black light' bulb, and filtered the lens for UV-only, would that produce the same result?

The eyes of course are a concern, but the eyes are closed.

I don't know if a flash would be safer or not, a shorter exposure time, but a more intense brightness.

Probably Ulf would have an idea.

[Andy Perrin]

Jonathan is the best person to ask for this, since he does the skin research, right?

[The Skin Doc]

I don't think he is using a flash. He says 4x 104W UV bulbs.

So that leaves a lot to the imagination. Do the bulbs emit any UV below UVA?

If it is just UVA, and not prolonged exposure, then I wouldn't think it would be that bad for the skin.

I have not tried this, but let's say I illuminate my hand with a common 'black light' bulb, and filtered the lens for UV-only, would that produce the same result?

The eyes of course are a concern, but the eyes are closed.

I don't know if a flash would be safer or not, a shorter exposure time, but a more intense brightness.

Probably Ulf would have an idea.

It's a blacklight bulb that's used by DJ's at clubs. Although it's 104W the light is not very intense.

[The Skin Doc]

I have heard mixed things about the significance of UV-apparent skin spots. Some have claimed that they are an index of skin damage whereas others seem to ridicule the idea. What is your personal take on this?

There are two sides to that coin. There are instances where genetically my patients have a lot of freckles, however the majority have significant sun damage. I live in the Caribbean where the daily UV index is above 11. I mainly give patients free "UV Assessments" to show them sun damage they have, as well as to show them the benefits of using sunblock.

[dabateman]

 

It's a blacklight bulb that's used by DJ's at clubs. Although it's 104W the light is not very intense.

 

That sounds like a woods glass covered incandescent light bulb. Do they get extremely hot?

If incandescent, then it will not go lower than 350nm. So possibly much safer than a black light mercury coil fluorescent bulb. I find they leak 335 and even some 313nm lines. But for a 13W mercury fluorescent coil light bulb you would get very little heat and much more UV than your 104W bulbs.

I have a 75W and 100W black light incandescent bulbs and they produce mostly heat and very little UV. They are actually designed to heat up to increase the UV output. So it maybe ok with your current light setup, for brief exposure.

[The Skin Doc]

That sounds like a woods glass covered incandescent light bulb. Do they get extremely hot?

If incandescent, then it will not go lower than 350nm. So possibly much safer than a black light mercury coil fluorescent bulb. I find they leak 335 and even some 313nm lines. But for a 13W mercury fluorescent coil light bulb you would get very little heat and much more UV than your 104W bulbs.

I have a 75W and 100W black light incandescent bulbs and they produce mostly heat and very little UV. They are actually designed to heat up to increase the UV output. So it maybe ok with your current light setup, for brief exposure.

No, the bulbs don't get hot at all. Thanks for the advice on the 13W Mercury light bulb. I'll try to source it this week.

[JMC]

Nice image and good to see the eyes closed for it. I need more friends with freckles for imaging :)

 

Not sure what the spectra are on these lamps, but if they are for night clubs then I am guessing UVA only, and while there is a risk with exposure, the risk is much lower than with UVB sources. Ideally the spectra of all light sources should be used should be known - without that knowledge, it is impossible to say how bad it is. I've been doing some work recently by using the lamp spectra in combination with something called the Erythemal action spectrum, to calculate safe exposure times for a light for imaging.

 

As for the worth of these images, my take is this. They can be used to emphasize the presence of UV induced skin damage before it becomes visible to the naked eye. This can then be used to educate about the correct sun protection, and how to reduce the risk of further damage. Any use like this is a good idea, and I am 100% behind that. I am not a fan of using for shock value - oh my lord, you're skin is so bad, and look at all these products we can sell you to make it better.

[dabateman]

 

No, the bulbs don't get hot at all. Thanks for the advice on the 13W Mercury light bulb. I'll try to source it this week.

 

Ok now I am confused. If they don't get hot then they ate either LEDs or fluorescent lights.

Can you provide a link to the light in question?

If Leds, you may have the best light source.

[Andy Perrin]

I've been doing some work recently by using the lamp spectra in combination with something called the Erythemal action spectrum, to calculate safe exposure times for a light for imaging.

Jonathan, this is interesting-- I know for X-rays there is already well-worked out dosimetry methodologies, so is this something similar?

[The Skin Doc]

Ok now I am confused. If they don't get hot then they ate either LEDs or fluorescent lights.

Can you provide a link to the light in question?

If Leds, you may have the best light source.

This is similar to the bulb I use, but from same company. Mine being 105W. I don't recall the bulb ever being hot.

[JMC]

Jonathan, this is interesting-- I know for X-rays there is already well-worked out dosimetry methodologies, so is this something similar?

I'm not sure about the X-ray one Andy, but yes, the erythemal response function (or erythemal action spectrum) is a way calculating a 'safe' dose of UV in a given time period before burning (and the redness that goes along with that) develops. I can dig out a paper on it when I have a minute, but there is a copy of the curve here - https://commons.wikimedia.org/wiki/File:Erythemal_action_spectrum.svg

 

While not infallible, as it is only based on redness as an endpoint, it is useful when calculating UV exposures.

[dabateman]

 

This is similar to the bulb I use, but from same company. Mine being 105W. I don't recall the bulb ever being hot.

 

That is a coiled fluorescent black light that I was referring to earlier. They are sometimes labeled as BLB bulbs as they have the black light (typically woods glass) filter on the bulb. You will get 335nm to 405nm out of them. Mostly 365nm mercury line, but 335 line and 405nm lines are there.

So you are hitting your subjects with the full UVA range.

You may think about getting a 385nm LED bulb, as you should still see the skin patterns, with less risk of UV exposure.

 

Something like this:

https://www.amazon.com/Sunmerit-385-400NM-Ultraviolet-Fluorescent-Blacklight/dp/B07ZRFSPC1/ref=asc_df_B07ZRFSPC1/?tag=hyprod-20&linkCode=df0&hvadid=385112208924&hvpos=1o15&hvnetw=g&hvrand=3149958212802217515&hvpone=&hvptwo=&hvqmt=&hvdev=m&hvdvcmdl=&hvlocint=&hvlocphy=9007779&hvtargid=pla-847613630297&psc=1&tag=&ref=&adgrpid=73789135330&hvpone=&hvptwo=&hvadid=385112208924&hvpos=1o15&hvnetw=g&hvrand=3149958212802217515&hvqmt=&hvdev=m&hvdvcmdl=&hvlocint=&hvlocphy=9007779&hvtargid=pla-847613630297

[The Skin Doc]

That is a coiled fluorescent black light that I was referring to earlier. They are sometimes labeled as BLB bulbs as they have the black light (typically woods glass) filter on the bulb. You will get 335nm to 405nm out of them. Mostly 365nm mercury line, but 335 line and 405nm lines are there.

So you are hitting your subjects with the full UVA range.

You may think about getting a 385nm LED bulb, as you should still see the skin patterns, with less risk of UV exposure.

 

Something like this:

https://www.amazon.c...la-847613630297

Thanks for your assistance. I will definitely source the 385nm LED bulb.

 

Also, how well do you think the below flood lights would work for my purposes? It's in UVA, but they seem to be used for parties.

[Cadmium]

What lens and what UV-only filter are you using?

[The Skin Doc]

What lens and what UV-only filter are you using?

I have a UV converted Canon 5D Mark III and a Canon 50mm Macro lens. That's all I use.

[dabateman]

Jonathan tested the transmission of the Canon 50mm Macro here:

https://www.ultravioletphotography.com/content/index.php/topic/3406-lens-transmission-in-the-uv-latest-update/page__hl__%2Bcanon+%2B50mm__fromsearch__1

 

Its 50% transmission at 380nm and 10% at 365nm. I would purchase any 385nm LED light source you find is reasonable.

[Andy Perrin]

I think this is all good - if you use 380nm LEDs you will get lots of light in a wavelength that seems to be not very dangerous for skin (and eyes are shut) and most lenses will pass plenty of 380nm, including your setup. You are probably already photographing mostly the long wavelengths anyway because of that lens.