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UltravioletPhotography

UVC, UVB, UVA bulbous flower


dabateman

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Warning, do not use 250nm UVC lights unless you take proper precautions. Image only in controlled room, away from pets, kids, loved and non loved ones. Best to image in dehumidified area, winter months work, to reduce air moisture. Ozone will build up quickly when working with UVc lights. Ideal to have a room vent. Tether your camera to a computer located in an other room to work with camera settings and images. This can be done with 25 feet long usb cords.

 

Adding to this warning, my New germicial bulb produced enough ozone that when I went down to the basement 2 hours after I shot the UVC images I could still smell the Ozone. Also WEAR Amber UVex glasses. I have a feeling my Orange ones leak not only at 380nm, but deep into UVC somewhere. The Amber UVex are the best.

 

So after getting all the do not try this crazyness out of the way. I got a new 193bp20 filter. It seems like it may be isolating the 185nm mercury line out of the germicidal bulb. But I don't think I see any striking difference from the 253bp25 filter.

 

Shot with KSS imager using 60mm Macro quartz lens. The 193bp20 and 253.7bp25 filters are 25mm and placed in the KSS filter holder behind the lens. The other filters are screwed in front of the lens with no other glass used. A Panasonic GM5 set to monochrome mode is used behind the imager with Olympus 30mm lens set with aperture F5.6. Most shutter speeds were 1/4 at ISO 200. So the imager did a good job at amplifying the UV signal.

 

Visible:

post-188-0-25034100-1576658454.jpg

 

Germicidal light 193bp20:

post-188-0-53194100-1576658479.jpg

 

Germicidal light 253bp25:

post-188-0-97725800-1576658494.jpg

 

All below shot with 2 Exoterra UVB 200 26W bulbs

303bp10 with U340 2mm behind to block mirror reflections:

post-188-0-22582100-1576658520.jpg

 

313bp25:

post-188-0-39757800-1576658535.jpg

 

335bp10 (we can see through my glass now):

post-188-0-31867400-1576658555.jpg

 

370bp15:

post-188-0-14875000-1576658569.jpg

 

390bp25:

post-188-0-18826400-1576658582.jpg

 

405bp10 (the back flower is now white):

post-188-0-08767900-1576658593.jpg

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Very cool images! It might pay to do some research on spectrums of different common materials so we could use that to verify some of these results. Like with SWIR, when I did my early fluorescent screen images, I used images of salt (which has a flat SWIR spectrum and high reflectance) and sugar (dark in SWIR) and water (dark in SWIR) to verify that I was, in fact, seeing SWIR. Something like that might be useful for checking the shorter UVC stuff if you can find spectra.

 

I'm not sure that 193nm result (while definitely interesting!) is quite "confirmed" yet, since we don't know how good the blocking of that filter is, nor whether the screen might be (for example) way more sensitive to 253nm (or other wavelengths) than 193nm, leading to an out-of-band situation. We need to think of some way to stack or something in order to verify that.

 

By the way, how exactly are you putting the other filters in the KSS/imager setup? Are you unscrewing the slider tray each time and replacing the filters? Could you take a photo of your setup for us?

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I have decided to just keep the 193bp20 in one slot and the 253.7bp25 in the other. They are very reflective and placing them behind the lens I think is best.

I then fully remove the filter holder and cover the lens with a black sock. Then screw all other filters in front of the lens.

 

This is for now. I am thinking of getting an automatic 8 position filter wheel that I could modify behind the lens. I may take off the slide filter section of the lens and make a custom M42 screw plate to the back to attach the wheel.

Since I don't need to stack filters, the slots would be 193, 253, 303, 313, 335, 370, 390, and 405.

Then with an automatic focus rail (to adjust focus shift due to filter thickness) and light switches, I could fully remotely control the images.

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Hard to say what in 200nm the 193bp20 shot is. But if you look in the glass you can see faintly a triangle leaf in the 303bp10 image, more so in the 313bp25 image. The glass is black without any leaf appearing in the 253bp25 or 193bp20 images. So I am in the 200's. Also the poor signal, more amplified noise in the 193bp20 shot also helps give me confidence that its low 200's as it also has less light through than the 253bp25 when stacked with my 330WB80 Improved filter, which is 260 to 380.

But a reference would be great. Also this flower wasn't very interesting. Something else, may look better.

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This is for now. I am thinking of getting an automatic 8 position filter wheel that I could modify behind the lens. I may take off the slide filter section of the lens and make a custom M42 screw plate to the back to attach the wheel.

Since I don't need to stack filters, the slots would be 193, 253, 303, 313, 335, 370, 390, and 405.

Might be easier to just buy more filter slides! They must be available somewhere.

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I actually haven't seen them and with an automatic filter wheel, the whole thing can be automatic.

But I don't have the money for that. So looking out for cheap sets on the bay. The automatic focus rail I would like is $1200. To get the rail and rotating section for the subject. Would be fun to rotate the subject for best light.

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It's interesting to see the glass gradually become more transparent accordingly with increasing wavelength - that's at least one way to prove UV imaging, generally speaking. Even more interesting is how the flower in the foreground (Safflower?) maintains its UV absorbance over a wide range, at least relative to the rest of the image. This would make me guess nature is quite intentional about it, with some ulterior motive/job.
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