UVA fluorescence of skin and nails

[JMC]

Was having a play today, and wondered what my hand would look like if photographed with my normal 'Non UV' camera but using the UVA flash. So here it is, front and back of hand, under norrmal daylight, and using the UV flash in a darkened room (without the flash and shot in the darkened room under these settings the image was just black). Interestingly the settings on the camera for the daylight shot and UV fluorescence shots were identical (1/125s, f10, ISO1600, in camera white balance, 50mm lens, Eos 5DSR 200EX-RT flash modified by ACS for UVA imaging). With hindsight, I should have run the UV fluorescence shots at a slightly higher ISO or slightly wider aperture as they are a little dark, but this was just a quick experiment.

 

Visible light photos

 

UV fluorescence

 

The dry skin from the small callouses on my middle and index finger show up quite well under UV (as I expected from doing dry skin imaging before), but I didn't expect the nails to show up quite as strongly. As I say above the settings weren't optimised here, it was just a play - bit difficult to hold the camera in one hand a take a picture of the other :)

[Guest]

I wonder, in regard to the keratin fluorescence - if it is absorbing UV (and re-emitting at longer wavelength..) - will it be UV dark? I'm surprised I haven't already checked this myself! Maybe later today... :)

[JMC]

Not sure Mark, not gone into the theory of what's going on yet. If keratin is UV dark, it isn't anywhere near as dark as the melanin in the skin under UV. I think the water content of the skin also has a huge impact on the degree of fluorescence - dry skin fluoresces strongly, while wet skin does not. Just realised I got my flash model wrong in the first thread. It was suppose to be 600EX-RT.

[Andrea B.]

All kinds of interesting experiments are now leaping onto my list.

 

Feet are horrible things, but I can't think of a better place to find calluses. In my case at least. :D But will I be embarassed to post what I discover? Probably. But in the interests of science.........