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UltravioletPhotography

Amethyst UV


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Especially if you are using a converted camera, probably the purple on the surface/table you see is UV. Do you have anything that blocks UV (like polycarbonate goggles) to test this? Or you can do the opposite, if you have a UV-pass filter that blocks visible (and preferably infrared) light, and you still see this glow when you put it on the lens with the same camera settings, then it’s UV.
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It could be two things: fluorescence or UV.

 

Since you see red reflections on the stove, I'm guessing it's UV, and I think I can even say it's 365 nm UV. That wavelength appears reddish when a "normal" visible light white balance is set (that's my personal experience and I have seen this 365 nm color on UVP too). A pure fluorescence image should not contain direct mirror-like reflections.

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It could be two things: fluorescence or UV.

 

Since you see red reflections on the stove, I'm guessing it's UV, and I think I can even say it's 365 nm UV. That wavelength appears reddish when a "normal" visible light white balance is set (that's my personal experience and I have seen this 365 nm color on UVP too). A pure fluorescence image should not contain direct mirror-like reflections.

That is why I am not sure about a uvir cut filter? Any advice on this would be appreciated.....
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There are a lot of filters that can be used. Some fluoresce a lot, some fluoresce less. If you haven't read it, I suggest reading the UVIVF sticky to find more information.

 

Since I never actually tried UVIVF myself (except with my phone), my experience is very little compared to other members here who did it much more. They can probably help you more than I can.

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I'm going to use the word "proper" informally. There is no requirement from UVP that you use double filtration for fluorescence photography. Of course we would urge you to do so. :lol:

 

Proper UV-induced Visible photography requires:

  • a filter on the illumination source to ensure that only UV light reaches the subject.
  • a filter on the taking lens to ensure that only Visible light reaches the sensor.
  • photography in the dark to avoid ambient light contamination.
  • placing the subject on a non-fluorescent background.

.

And please remember that even if a non-converted stock camera/lens is used to record the Visible fluorescence,

such gear can still sometimes pass a bit of either UV or IR. So stock gear must filtered too.

 

I'm curious about how well you can filter a flash like the Youngnuo? They are so strong that unwanted light could possibly get through the filtration?

 

Usually when we see that violet/purple color we say it is due to leakage from the illumination source.

 

All this is written up here: Sticky :: UV Induced Visible Fluorescence

In particular scroll down in the Sticky to read about the Shiny Metal Test which shows the violet/purple color.

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I think as another member kindly pm'd me to say that my 3d printed part is leaking ir. I am now conjuring up an idea to coat it in something to block it.
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Thanks guys sure will let you know. I did consider paint also considering rubber. Or maybe even just foil tape for now. I am guessing the light leaks through the layers as I have seen 3d printed boats that need to be sealed before use. I am new to this world of UV and am learning as I go along. Thinking about this stuff
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Andy Perrin
Don't use any paint or sealant until you test that it's opaque to UV and IR as well as visible. Plenty of things are "black" in visible light but white or transparent in IR.
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At this point the foil is a temp thing. I am wondering if IR can go through resin? As that is another option for printing these holders with resin printers being more affordable these days. Anyway now I wait for it to get dark so i can take some more images and test my newly modified flash.
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Andy Perrin

I would guess that IR would pass through resin. It will depend on what dyes may be mixed in of course to color it.

 

I know old fashioned PCBs are translucent in IR.

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Thanks . I guess the only option is to print and then cover with foil coated tape. At least I found out this issue finally. I have had some personal problems so have not been able to do any more testing for a year and a half.
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Test it out first. The holder needs to be taped up around the edges, especially on the top, those places are the most likely places for it to leak.

Keep in mind that there is some visual red in the permitted UVIVF visual range which would not be considered leaks.

Only above ~700nmn~, a threshold that is up to the user, and not specifically defined. The upper end can be tested.

There are barrier filters for UV, IR, and UV/IR to use on the lens, but limiting the flash spectrum should be first in mind i think.

Try an IR filter on the camera to test for leaks, and block out the filters.

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Test it out first. The holder needs to be taped up around the edges, especially on the top, those places are the most likely places for it to leak.

Keep in mind that there is some visual red in the permitted UVIVF visual range which would not be considered leaks.

Only above ~700nmn~, a threshold that is up to the user, and not specifically defined. The upper end can be tested.

There are barrier filters for UV, IR, and UV/IR to use on the lens, but limiting the flash spectrum should be first in mind i think.

Try an IR filter on the camera to test for leaks, and block out the filters.

 

I have covered the whole adapter in foil and then taped over the top wont be any ir leak now haha

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