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UltravioletPhotography

UVIVF: Shortwave (254nm / UV-C) vs. Midwave (UV-B) vs. Longwave (395nm / UV-A)


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EDITOR's NOTE: Please read our post UV and Your Eyes :: UV Safety Reference.

You must always wear protective UV-blocking goggles when using artificial UV illumination.

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Would be nice to see examples of visible flourescence of the exact same objects/material but under different UV lighting. Haven't seen any posts about this topic on this forum.

 

I'm very early in my tests, but mirrors look interesting under shortwave, as do minerals. Need to do many more comparison tests.

 

What shortwave/midwave lights can you reccomend? It would be ideal to get one light that has all 3, and that is bright.

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WARNING...UV photography is dangerous to your eyes particularly & to your skin too.

Please wear polycarbonate safety goggles that seal around the face & long sleeve protective clothing.

It is best to remain within the UVA range. UVB & UVC will destroy DNA.

Col

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EVAN, PLEASE TELL ME YOU HAVE UV PROTECTIVE GOGGLES FOR YOUR EYES?

Especially if you are using mirrors or other reflective surfaces??

 

We have no recommendations for shortwave UV illumination

because we think 254nm should be left alone.

 

254nm UV illumination is extremely dangerous.

 

For more information you might want to check rock/mineral sites and reptile lighting sites.

 

Sorry to be so alarmist, but really.......even ordinary UVA damages the eyes over time.

How do I know this? Well, sigh, I've just had the 4th surgery on my left eye.

It all started with a double cataract at a young(-ish) age and went downhill from there.

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I understand it is ideal to wear UV-A/B/C blocking eye wear and to not look directly at or be near something that is emitting electromagnetic radiation with wavelength frequencies that are shorter than visible light, and that it would be more ideal to wear clothing that covers all body parts, and that UV-C is more damaging than UV-A or UV-B.

 

I was using a 4W shortwave bulb (low power, extremely dim) with UV-A/B/C blocking glasses and was not placing my hand in front of the light.

 

Wouldn't either looking directly at the sun or just being outside in the sun (a very powerful UV-A/B/C emitter, although only UV-A/B gets past Earth's atmosphere) be more damaging to eyes/skin/DNA than looking directly at or being near a 5W 365nm Nichia UV-A LED?

 

I can't seem to find much information online regarding protection against UV-C and how it is different than UV-A or UV-B. Why is it that they (mineral collectors) use UV-C but none of you guys do? If it is extremely dangerous, do they not recognize that?

 

 

Andrea, you said you got a cataract at a young age, was that really caused by looking at UV light sources?

 

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Some links:

 

http://www.ccohs.ca/...tradiation.html (article comparing UV light and some exposure/damage scales)

 

https://en.wikipedia...iation_hormesis (hypothesis says small amounts of radiation exposure over long periods of time is good for you (I think of the sun), in the same way that when you workout/exercise, you are destroying muscle fibers, but after they are repaired they are stronger than before. This doesn't have much to do with UV-C, but looking at UV-A with this in mind makes it kinda seem like UV-A is not as big of a deal... then again, the 5W UV LEDs are physically closer to your body than the sun is, so the only way to know for sure would be to objectively measure the uv output of the sun by the time it hits the earth, and the UV LED when it is close to you. If the UV LED is less intense than the sun, then I don't see why I would need to wear protective clothing in the same way I don't cover 100% of my body when I go outside for a few hours, going in and out of direct sunlight. I suppose ideally, yes, you could increase your lifespan and lower the chances of getting cancer and damaging DNA/skin/eyes by not being exposed to any amount of radiation that has higher frequencies than visible light, but on the other side of the coin, you can potentially enjoy life more by doing activities where you are exposed to radiation, like being in the sun, riding in an airplane, or using UV-A/B/C lighting with UV-A/B/C blocking glasses for 0-60 minutes for a few days to get a dozen or so UVIVF images. Is that really extremely dangerous?)

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I don't think anyone here is going to debate this with you. Do the research and decide for yourself based on facts, not suppositions.

Links below.

 

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We use and recommend UV-protective goggles to limit exposure from our sources of UV-illumination. Go thou and do likewise.

 

You cannot photographically record anything in the UV-C range with current sensors. So UV-C is out from the get-go even if you had filters which would pass the UV in that region.

It starts to get tough to record around 320-330nm. UV-B starts around 315nm. So most likely UV-B won't be photographed either.

 

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https://en.wikipedia.org/wiki/Ultraviolet

UV-C (O% of UV in sunlight) is germicidal and breaks DNA.

UV-B (~5% of UV in sunlight) is dangerous for cataracts, retinal damage and skin cancers if overdone.

UV-A (95% of UV in sunlight) causes skin wrinkles if overdone. But if you stare at it directly you can burn your cornea.

UV, overall, is about 10% of sunlight.

 

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https://en.wikipedia.org/wiki/Photokeratitis

Photokeratitis or ultraviolet keratitis is a painful eye condition caused by exposure of insufficiently protected eyes to the ultraviolet (UV) rays from either natural (e.g. intense sunlight at high altitudes) or artificial (e.g. the electric arc during welding) sources. Photokeratitis is akin to a sunburn of the cornea and conjunctiva, and is not usually noticed until several hours after exposure. Symptoms include increased tears and a feeling of pain, likened to having sand in the eyes.

 

The injury may be prevented by wearing eye protection that blocks most of the ultraviolet radiation, such as welding goggles with the proper filters, a welder's helmet, sunglasses rated for sufficient UV protection, or appropriate snow goggles. The condition is usually managed by removal from the source of ultraviolet radiation, covering the corneas, and administration of pain relief. Photokeratitis is known by a number of different terms including: snow blindness, arc eye, welder's flash, bake eyes, corneal flash burns, flash burns, niphablepsia, or keratoconjunctivitis photoelectrica.

 

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https://en.wikipedia.org/wiki/Actinic_conjunctivitis

Actinic conjunctivitis is an inflammation of the eye contracted from prolonged exposure to actinic (ultraviolet) rays. Symptoms are redness and swelling of the eyes. Most often the condition is caused by prolonged exposure to Klieg lights, therapeutic lamps, or acetylene torches. Other names for the condition include Klieg conjunctivitis, eyeburn, arc-flash, welder's conjunctivitis, flash keratoconjunctivitis, actinic ray ophthalmia, x-ray ophthalmia, and ultraviolet ray ophthalmia.[1]

 

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https://en.wikipedia.org/wiki/Health_effects_of_sunlight_exposure

The ultraviolet radiation in sunlight has both positive and negative health effects, as it is both a principal source of vitamin D3 and a mutagen.

 

Long-term sunlight exposure is known to be associated with the development of skin cancer, skin aging, immune suppression, and eye diseases such as cataracts and macular degeneration.[7] Short-term over-exposure is the cause of sunburn, snow blindness, and solar retinopathy.

 

 

A serious concern is the "blue light hazard" which is the temporary or permanent scarring of the retina due to its sensitivity to blue light, around 440 nm wavelength. Blindness may result.

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I don't think anyone here is going to debate this with you. Do the research and decide for yourself based on facts, not suppositions.
I see myself as asking questions, not debating/arguing, trying to convince/persuade, or weasel my way out of not taking safety into consideration.

 

We use and recommend UV-protective goggles to limit exposure from our sources of UV-illumination. Go thou and do likewise.

Already do. I also have prescription eye-wear with a UV-blocking coating on them (I can tell because when I take a picture of them with UV-only light, the lenses are black. I also wear sunglasses on top of those when I'm outside.

 

You cannot photographically record anything in the UV-C range with current sensors.

I was originally talking about UVIVF, but this is useful information.

 

As far as the links, thank you for those. I need to look at them in more detail to see if they distinguish between shortwave/longwave - I am trying to figure out the adequet levels of protection needed for each category of UV. I'm super tired right now and haven't yet had the time to read it in depth (same with some of your other responses on other posts)

 

side note: blue-green light also stops melatonin production. it is good to wear blue-green blocking glasses after sundown or 1-2 hours before bed in order to increase circadian rhythm synchronization so you can sleep better. Using orange glasses when doing UVIVF photography at night would be a good idea too, even though you can't see colors as good.

 

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My questions still remain:

 

1. Wouldn't looking directly at the sun or having direct sunlight on your skin for 0.5-10 seconds be more damaging to eyes/skin/DNA than looking directly at or having skin exposed to a 5W 365nm Nichia UV-A LED for 0.5-10 seconds?

 

2. Is there an adequate form of protection that can be used to block the harmful effects of a UV-C light? (There is for eyes [the goggles], but if that is not enough protection for skin/DNA, then what is?)

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I see myself as asking questions, not debating/arguing, trying to convince/persuade, or weasel my way out of not taking safety into consideration.

 

I do apologize if I sounded judgey!!!! I certainly did not intend to sound that way!! I do know you are asking questions. I was just trying to indicate that the UV safety topic is one that most of us just take for granted and don't discuss the details about. We just tell folks, just use your UV goggles and use common sense. If you can block the UV, then block it. Sometimes on the 'net, it is difficult to convey the nuances of the response.

 

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Already do. I also have prescription eye-wear with a UV-blocking coating on them (I can tell because when I take a picture of them with UV-only light, the lenses are black. I also wear sunglasses on top of those when I'm outside.

 

What you want to be careful with when using UV-flashes, UV-LEDs or UV lamps is the bounced reflections which can enter around the sides of ordinary eyewear. UV goggles wrap around the eyes. The violet and shorter blue waves are also damaging to the retina.

 

Think ski goggles. Skiers have wrap-around UV goggles to prevent snow blindness caused by reflected UV/sunlight.

 

Also, it is not the single UV exposure which is necessarily damaging that one time. It is the cumulative UV exposure over time.

If not using proper protection then when you inevitably reach middle age, the dermatologists will start frying skin lesions off your face and the eye surgeons will be scraping the cataracts out of your eye.

Please do not ask me how I know this. :rolleyes: :D :D (I'm really not middle aged, only pretending to be to give myself some gravitas.)

 

If using a UV-A/B UV flashes, then just closing your eyes when you push the shutter is sufficient. If you have your UV lamp or UV-LED mounted in such a way that you can switch it on/off easily, then also close your eyes. Really just easier to don the UV goggles.

 

 

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1.) I have no data to answer this one. [ADDED: But skip to the next post for a calculation we once did.]

Although most of us have some scientific background, it doesn't really include lab studies for UV exposure. ;) I'm going to look for a link I once found to the recommendations from OSHA (or was it the welders' union??) about recommended length of UV exposures.

 

2.) I have no answer for this one either because none of us are using UV-C.

Look around on medical sites or water purification sites for information. If I get some time today, I'll also try to look. If we find any good links, then we can share them with everyone.

 

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JD, are you reading this? If so, do you happen to know from your UV work whether the standard UV goggles also block UV-C??

 

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HERE IS A LINK TO A PREVIOUS CONVERSATION ABOUT UV PROTECTION

http://www.ultraviol...-is-bad-for-me/

 

In the next post I will repeat some info from that thread.

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Here is a sample calculation about the intensity of UV-in-sunlight versus the Blak-Ray lamp.

This calculation was prompted by Damon's questions about UV exposure: http://www.ultraviol...-is-bad-for-me/

As always, anyone spotting any errors or misinformation should please notify us immediately, thank you.

[i really do need to work on an index of topics so that we can easily retrieve this stuff.]

 

We can try to repeat this calculation for UV-LED torches.

 

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All radiation from sunlight is equivalent to an intensity of 1.36 kiloWatts/m2

at the distance from sun to earth.

That translates to 136000 microWatts/cm2 at the distance from sun to earth

because 1kW = 109 µW and 1 m2 = 104 cm2.

 

At ground level sunlight consists of about 3% UV.

 

Therefore UV-in-sunlight at ground level has an approximate intensity of 4080 microWatts/cm2

at the distance from sun to earth.

[This may vary by season, altitude, cloud cover or other variables.]

 

The Blak-Ray mercury lamp outputs 8190 µW/cm2 at 10" (about 25 cm).

[Later this figure is given as 8900. Don't know which is correct.]

 

Conclusion: The Blak-Ray mercury lamp is twice as powerful at 10" as the UV-in-sunlight.

 

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Exposure Limits for UV Light

from the microscope company Ted Pella, Inc. about Blak-Ray lamp exposure.

.........total irradiance incident upon the unprotected skin or eyes should not exceed

an intensity of 1mW/cm² for periods greater than 17 minutes

........the Blak-Ray delivers an intensity of 21.7mW/cm² at 5 cm and 8.9 mW/cm² at 25cm (about 10")

 

American Conference of Governmental Industrial Hygienists (ACGIH)

Same exposure info.

........no more than 1 mW/cm2 per every 1000 seconds (about 17 minutes).

 

So if the Blak-Ray is outputting 8.9 mW/cm², you have 112 seconds in which to safely (?) expose yourself to it.

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So now we need to compare UV-in-sunlight's intensity of 4.08 mW/cm2 to the output of a 365nm Nichia UV-LED.

We also can set a limit in seconds for exposure to the Nichia output.

 

To do this properly you must know what kind of Nichia chip your torch is using because there are different grades of Nichia chips.

 

So if anyone has any Nichia intensity output data, let me know and I will divide it into 1000 for you. :D ;) :rolleyes: :D

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I have the UK version of the MTE torch, which is called the "NightSearcher" torch. As far as I can from online pictures, they look exactly the same.
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enricosavazzi

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2. Is there an adequate form of protection that can be used to block the harmful effects of a UV-C light? (There is for eyes [the goggles], but if that is not enough protection for skin/DNA, then what is?)

 

UV-proof clothing that completely covers all skin. Think of an environmental suit opaque to UV. In other words, the UV-blocking goggles must sit tight against a hood that covers the rest of the head, just like you see in CDC protective clothing. Since you must avoid reflected UVC from reaching any part of the body, no gaps are allowed anywhere, especially around the eyes. The goggles must allow ventilation only through built-in light traps.

 

For the same reason, it is not allowed to operate UVC lamps for water sterilization except within light-tight containers. In other words, you can either completely shield the lamp, or completely shield the photographer.

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UV-proof clothing that completely covers all skin. Think of an environmental suit opaque to UV. In other words, the UV-blocking goggles must sit tight against a hood that covers the rest of the head, just like you see in CDC protective clothing. Since you must avoid reflected UVC from reaching any part of the body, no gaps are allowed anywhere, especially around the eyes. The goggles must allow ventilation only through built-in light traps.

enricosavazzi, just curious, if that is how you would describe adequate levels of protection for UV-C, do you have a description for adequate protection against UV-A and UV-B?

 

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Now I just need to know what qualifies as UVC-proof clothing, or how to get a UV-C protection suit....

 

Protecting the head/face is the trickiest part, as you basically need an entire mask. Everything else seems like it could be done easily and without a full suit though (esspecially when working with weaker UV-C radiation sources); I would think if you were to wear UVC-blocking shoes, pants, gloves, and a long sleeve shirt or hoodie, and then the special mask, that you would be good to go, because the materials would overlap each other. If working with stronger UV-C radiation then yeah a suit would be better.

 

Do you think you need protection even when working with the little 4W UV-C portable ebay lamps? None of the ebay/Amazon listings have safety warning on them, if I remember correctly.

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You always need protection when exposed to UV-C lamps without exception.

 

No need to build a space suit, it is much simpler to place the UV-C lamps in a aquarium or terrarium with a light tight lid (cardboard & duct tape).

 

The normal glass will not transmit UV-C but will pass the longer UV-A so still wear protective eyewear. This will of course create issues of photographing through the glass but there are lots of folks photographing fish so you aren't reinventing the wheel.

 

If you absolutely cannot shoot through the glass then get a big cardboard box and set up your camera with a remote shutter so that you can enclose the whole rig in a light tight enclosure. Focus under regular light then turn off the focus lamp. Shut the box and tape the light leaks before plugging in the UV-C lamp. Trigger the shutter remotely however you like and turn off the UV-C lamp before opening the light tight box. If you can control the camera remotely even better - keep shooting.

 

One caveat, UV-C can degrade plastics and fabrics and fade finishes rather quickly. Irradiating a nice camera and any other objects inside the light tight enclosure may damage them, so you might want to use black felt drapes to protect your expensive gear.

 

Keep it light tight and out of sight!

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Only the few lenses that go down that deeply into the UV, unfiltered, could ever put those wavelengths on the sensor and even a so called naked sensor has a thin cover glass which likely significantly attenuates UV-C. I do not think anyone who ever reported bare sensor response ever showed any response down that far. That said, exposing a bare sensor to very short wavelengths would risk damage to any photolabile material in the assembly. For that matter even an unmodified camera has plastics and adhesives and gaskets and such that could fry in those angry photons!

 

I have however occasionally wondered what UV in general is doing to the dyes in the CFA. UV stability of the dyes was probably not a criterion in design of digital camera sensors other than to filter it out. Could the near UV wavelengths we are imaging by removing the protective filters conceivably fade or photobleach the dyes?

 

I do not recall any mention, but would like to pose the question to the more experienced UV photographers here. Have any of you ever noticed subtle changes in false color response as a converted camera ages?

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No need to build a space suit, it is much simpler to place the UV-C lamps in a aquarium or terrarium with a light tight lid (cardboard & duct tape).

That is a good idea

Of course, you wouldn't want to photograph certain things with UV-C if it were in a fishtank, such as fish :D

Even though, this is exactly the type of thing I am wondering about (UVcIVF of biological systems and landscapes)

If you were light painting landscapes with UV-C, lets say, just rock/mineral/dirt/urban landscapes, with a really bright lamp, you would need a space-suit, but maybe it would be totally worth it, who knows - I don't know of anyone who has even tried UVcIVF photography except with minerals and stamps.

But if the landscape had trees/plants/grass, maybe the UV-C would severely harm the trees/plants/grass :rolleyes: ...but maybe the exposure would be short enough that it wouldn't? plants are out in the sun all day which has UV-A and B, but not C...

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As I initially noted above:

You cannot photographically record anything in the UV-C range with current sensors.

So UV-C is out from the get-go even if you had filters which would pass the UV in that region.

 

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John, thanks for the warnings that UV-C could affect more than just the sensor.

 

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Have any of you ever noticed subtle changes in false color response as a converted camera ages?

 

No, not so far. But then UV false colour is not particularly nuanced in the first place. :rolleyes:

 

If the UV eventually affects the Bayer dyes, any of us using our converted cameras for visible work will more easily see it begin to happen there I think. So far with my D600, the earliest visible colour profiles I have made still work just fine to apply to recently made photographs. This has been over the course of only a couple of years though.

 

In Photo Ninja the metrics and data set of the colour profiles can be examined. Also the corrected colours can be looked at too. So if earlier and later colour profiles are examined at that level, gross changes in Bayer dye response might be detectable ? This kind of profile comparison would assume, however, that the colour profiles to be compared were made with identical lenses & filters & illumination.

 

I hope Bjørn (who has been traveling) eventually sees this as he has some converted cams which have been in use longer than mine. I kept upgrading until I got to the D600 so didn't use any of them for more than 2-3 years.

 

Somewhere we had a discussion once about whether the Bayer dyes fluoresced.

 

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Pylon - perhaps you can start explorations of the environment with UV-A and eventually work your way down?? :D Maybe someday UV-C will be feasible with the right protective fabrics, etc.

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I may have posted this before, or I may have thought better of it:

 

Fluorescence of dyes

 

This is yet another attempt to resolve the question of whether or not the dyes used in the Bayer array over a digital sensor could be fluorescing under the influence of UV (or any other) radiation.

 

ARE YOU AWAKE MURPHY?

 

That should make sure that a suitably large amount of egg speeds its way onto my face.

 

I have tried many times to find out any real information about the dyes used in Bayer arrays. Due to the commercial sensitivity even the chemical names are usually hidden and I have not been able to find any spectroscopic data on any candidates, such as Solvent Red 8 mentioned in Wiki as a potential Bayer array dye.

 

The dyes used are probably azo dyes due to their photo stability and widespread commercial use. I personally doubt that dyes have been specially synthesised for Bayer arrays, but we will never know.

 

I came across an interesting paper on absorption and fluorescence spectra of “disperse red 19” one of the simpler versions of an azo dye.

http://nopr.niscair.res.in/bitstream/123456789/24376/1/IJPAP%2051%2812%29%20833-836.pdf

The paper above cites the absorption spectrum of azobenzene, the simplest molecule with the azo grouping, as four absorption peaks at 223, 258, 314 and 420 nm in 15% ethanol. The peaks of a dilute ethanol solution of disperse red 19 were at 285 and 495 nm. The shift in wavelength was ascribed to the larger molecular structure compared to azobenzene. Solvent red 8 has even larger molecular structure so the absorption peaks would be expected to be shifted to even longer wavelengths. The spectral response of a CMOS sensor had a peak response for the red pixels at about 650 nm.

 

The fluorescence spectra of a dilute ethanol solution of disperse red 19, excited by a wavelength of 250 nm had fluorescence peaks at 324 and 640 nm.

 

You can also read about what it takes to be a “fluorophore”

http://en.wikipedia.org/wiki/Fluorophore

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Thanks very much for this Dave

I am finding this business of molecule size (nanotechnology) & the wavelengths reflected very facinating, it is called structural colour. I haven't found much about it online yet.

Cheers

Col

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You cannot photographically record anything in the UV-C range with current sensors.

So UV-C is out from the get-go even if you had filters which would pass the UV in that region.

Yes I know, I was talking about 254nm UVIVF (or UVcIVF as I was calling it)

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So now we need to compare UV-in-sunlight's intensity of 4.08 mW/cm2 to the output of a 365nm Nichia UV-LED.

 

We also can set a limit in seconds for exposure to the Nichia output.

 

To do this properly you must know what kind of Nichia chip your torch is using because there are different grades of Nichia chips.

Do you know what chip is in the popular MTE 301 torch that everyone seems to be using?

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Here is a test I took outside, left shoe is sunlit only, right shoe has the MTE 301 365nm UV-A LED shining on it. So, by the looks of it, the UV-A LED seems to be about 4x as bright as the sun. If it was 4x, I suppose you could say that if you were to stand 1-2 meters in front of this UV LED for 8 hours, that would be the same thing as standing out in the sun for 32 hours?

 

post-79-0-39044300-1437327385.jpg

 

and here is the same image converted to black and white, with a -2 EV Stop brush stroke applied to the right shoe to equalize them. Remember that every time you go up or down a stop, you are doubling or halving the amount of recorded light when compared to the original.

 

post-79-0-34237100-1437327844.jpg

 

So from this, assuming the PS software is accurate, I suppose you could conclude that the MTE 301 UV-A LED is roughly 4x as bright (or 2 stops) more powerful than the sun, in terms of UV-A radiation.

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well, that was all over the map.......

somewhere sometime this "conclusion" is going to lead to no good end...... :D

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Dave, about those dyes.

If you look through the various patents from Bruce Bayer and Kodak, you can find this about the dyes:

 

Photo-bleachable dyes are selected from the group consisting of:

  • chromylium and thiachromylium dyes;
  • pyrylium and thiapyrylium cyanines; and
  • flavylium and thiaflavylium cyanines.

 

Linkie: http://www.google.com/patents/CA1141584A1?cl=en

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well, that was all over the map.......

somewhere sometime this "conclusion" is going to lead to no good end...... :D

?

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