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UltravioletPhotography

UVC, UVB, UVA and fluorescence of a White Flower


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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.

 

I imaged a white flower using both the Sirchie Monochrome imager, coupled to my GM5 camera and using my EM1 just to compare the UV reflectance. I have also included some fluorescent images as they seem the most fun. Although the UVC and UVB do show some petal damage or something not visible in the visible or upper UVA range.

 

Also it looks like the Sirchie phosphor screen may be sensitive from 200nm to 500nm, as I do see an image using the Lee 729 filter used for IRchrome imaging. It gets very glowly the higher you go, But didn't test the absolute upper cut off.

 

Visible image of Flower:

post-188-0-15819500-1575620756.jpg

 

253bp25, using single UVC light:

post-188-0-75258400-1575620788.jpg

 

303bp10 +330WB80 improved filter, using two UVB lights:

post-188-0-42597300-1575620802.jpg

 

313bp25 +330WB80 improved filter, using two UVB lights:

post-188-0-41938700-1575620826.jpg

 

370bp15 +330WB80 improved filter, using two UVB lights:

post-188-0-18969300-1575620953.jpg

 

390bp25 filter, using two UVB lights:

post-188-0-55263900-1575620969.jpg

 

405bp10, using two UVB lights:

post-188-0-16508300-1575620983.jpg

 

Lee729 with KG3 2mm using two UVB lights:

post-188-0-13628200-1575620999.jpg

 

 

The following images for comparison using EM1 full spectrum camera with UAT lens at F8 with two UVB bulbs

 

Visible:

post-188-0-31244600-1575621483.jpg

 

U330wB80 filter only (UVA):

post-188-0-57933900-1575621499.jpg

 

U330WB80 + 313bp25 (UVB):

post-188-0-49619300-1575621521.jpg

 

Then for some fun here is the UV induced images using two 365nm lights with ZWB1 filters, Using the UAT at F8 on the Full spectrum EM1 camera:

 

UVIVF (using Sigma SD15 filter to block under 405nm and over 680nm):

post-188-0-47373300-1575621539.jpg

 

UVIVIRF (using just a Tiffen 2A filter on the camera):

post-188-0-93731300-1575621562.jpg

 

UVIIRF (Using as LP 720nm filter on camera):

post-188-0-16659900-1575621581.jpg

 

Here is a better IR induced fluorescence image using a 405nm light and the LP 720nm filter

 

405 IIRF:

post-188-0-71332400-1575621596.jpg

 

 

 

313bp25 +330WB80 improved filter, using two UVB lights:

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The UVB light I am using is a broad spectrum ExoTerra light. It has a very sharp peak at 313nm, but also light throughout the UV range. When you first turn them on, you even get the low pressure 254nm and 297/303 lines. So I can use it briefly for the 303bp10 filter shots.

As for why then I use it for UVA, is it tails off into 380nmish area. So images are more golden with Baader venus filter or the 330WB80 improved filter. I tend to like that yellow gold look of deeper UV than the blue lookof over 375nm. That's also why I like to image in the lower UV.

 

Also for those interested, thats a high tech Q-tip holding up the flower. After looking at this series, I could try white balancing off it. The head of the cotton is not glowing in the left.

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I love this series, thanks for making it!

 

One thing that anyone hoping to use a phosphor screen for scientific imaging should be aware of (and even for artistic imaging to some extent) is that the screens, for physical reasons, can have a strongly non-linear response to light of different intensities. A scientific user should measure the gamma curve to linearize the results, and artistic users may want to curve the image a bit.

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Thank you very much for sharing David.

 

It is interesting with this wide span of wavelengths.

They are quite out of reach with my camera and lenses.

 

It would have been wonderful if there were a camera with a sensor with good sensitivity and a bayer matrix with dyes specially optimised for the UV-A and UV-B range, allowing us to make one exposure to grab all of the range.

 

I know it is impossible, but in our dreams...

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Thank you very much for sharing David.

 

It is interesting with this wide span of wavelengths.

They are quite out of reach with my camera and lenses.

 

It would have been wonderful if there were a camera with a sensor with good sensitivity and a bayer matrix with dyes specially optimised for the UV-A and UV-B range, allowing us to make one exposure to grab all of the range.

 

I know it is impossible, but in our dreams...

 

I don't know if I understand your dream.

The quantum efficiency is quite low in both the UVa and UVb. Also finding the best lights can be a challenge.

That is why I have purchased filters on the mercury lines and use various mercury lights.

More powerful mercury lights would be nice but then they would be crazy dangerous. I already don't like to use my 302nm bulbs as they are hard to keep safe as they are large tubes and not fixtures for desk lamps.

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I don't know if I understand your dream.

The quantum efficiency is quite low in both the UVa and UVb. Also finding the best lights can be a challenge.

I think he had in mind a non-silicon (or not JUST silicon) sensor. Like with the TriWave being Ge-on-CMOS for SWIR. Something similar might be possible for UV.

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I couldn't resist, but used three of your images to assemble a trichrome: 253, 313, and 370. I don't get to see many trichrome UV images. Registration is not so hot due to CA, but I did not take the time to compensate for that.

 

post-66-0-42690600-1575689174.jpg

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I couldn't resist, but used three of your images to assemble a trichrome: 253, 313, and 370. I don't get to see many trichrome UV images. Registration is not so hot due to CA, but I did not take the time to compensate for that.

 

post-66-0-42690600-1575689174.jpg

 

That looks great. What wavelength is for which of the RGB?

Yes I find that you have to do the Bernard step with Hugin align stack tool, first.

 

I like lowest for R, as when I was patient with focusing my 280bp10 filter, the color on my Em1 was red. Then 303, 313, 335 all look green. The 380+nm bands look blue off my EM1, so that is why I have used those. Also has a nice yellow, usually.

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I think he had in mind a non-silicon (or not JUST silicon) sensor. Like with the TriWave being Ge-on-CMOS for SWIR. Something similar might be possible for UV.

That is correct.

Dreaming must not only include currently available technologies.

What we (mostly) are doing is to take advantage of and use accidental properties of developments made for the mass market for normal digital cameras.

Research is often costly and focus on where it give the best payoff. This is true for filter materials, sensor technology etc.

 

I was just playing with an unrealistic idea.

What we could have if there would have been more work done and a market for affordable sensor designs with a much better efficiency deeper into the UV-range.

What if such a sensor had bayer matrix materials with their main peaks in that range and not for RGB. Then there would possibly also be some useful strong light sources with good continuos UV-light.

 

If all such things were possible to have I think we could have even more interesting colourful images without such trouble with making composites from many images like the one created by OlDoinyo above.

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