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UltravioletPhotography

UV light wavelenghts?


Aurora

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Hi,

 

I'm considering purchasing UV LED lights at specific wavelengths. I know that 365 nm, 385 nm and 395 nm are commonly use but wondering if some of you have experience with other wavelengths (360nm, 350 nm, 340 nm, etc.) and if the results are different than with the 365 nm wavelength? if it allows to see other things? Also is there a big difference between 385 and 395?

 

Thank you in advance for your help!

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I haven't seen any UV LEDs at wavelengths, 360nm, 350 nm, 340 nm, etc.

I haven't seen anything that shows any differences between 385 and 395nm.

Cheers

Col

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Hi Aurora,

 

​my opinion about LED-lights in brief: very helpful for focusing, less helpful to get nice colors. Better use a flash (or LED for focusing plus flash for pictures), ​the LEDs tend to have a small band, where they emit light around the peak wavelength. (If you only have the peak wavelength, like with a good laser (a coherent light), you get a monochrome picture, which is equivalent to a black and white picture)

Some cheap old flash with a "bad" coating to suppress UV will do.

 

Werner

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enricosavazzi
There are LEDs that emit wavelengths as low as 280 nm and perhaps less, but very expensive and the intensity of the emitted radiation is too low to be usable for our purposes. Some of these LEDs even self-destroy relatively quickly in normal use, because the generated UV degrades the chip. In practice, below 365 nm, one should look to other UV sources for digital imaging.
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Hi Aurora, I don't have experience with any other UV range LED's than the 365nm Nichia (MTE torch), but I find your question fascinating, and I would be interested in sources for these other UV range LED's that you have found.

I think it would be interesting to experiment with a set of them, as long as they were not terribly expensive.

 

Also, Werner mentioned the LED's tend to have a narrow band. Recently I had seen some very monochrome UV photos that were shot using 365nm LED illumination.

So I did this test below to prove to myself that my 365nm MTE torch light didn't have much band width, and thus was the reason for the monochrome look of the photos I had seen shot with 365nm LED's.

Pardon the uneven lightning with the MTE shot, as it was a somewhat larger area to 'paint' with the torch light than I was use to.post-87-0-55222200-1457601045.jpg

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Although the UV-LED flashlights (torches) are somewhat narrowband, the 385nm is not narrowband enough to produce only UV. It also gives out a lot of visible light in the violet and violet-blue range. Therefore it is not the best to use for actual UV photos. This is not to say that it isn't fun to play with and to use in comparisons.

 

I would think a 395nm LED outputs primarily visible light.

 

Remember that the division between UV and Visible light is regarded as being somewhere between about 380-400nm depending on who's doing the talking. :D So if your purpose is strictly UV work and you don't mind a monochrome output in your final photo, then the 365nm UV-LED is the best choice. Most UV-LED 365nm chips also do produce a tiny amount of visible light, but it isn't enough to worry about unless you are doing fluorescence work.

 

As mentioned above, there are probably no commercially available UV-LED lights below 365nm.

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