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ORIGINAL DATE: 2021 August 29 UPDATE 1 Aug 2023. Removed UVR Optics NIR-Block because not strong enough at OD2 in some regions. Replaced with reccie for BG39. UPDATE: 22 May 2023. Added suggestion for finding Schott/Hoya UV dual bandpass glass now that UVIR*Optics has gone out of business. UPDATE: 22 May 2023. Added AndreaU MK II and UVBplus to Name Brand Filter list.\ UPDATE: 9 April 2024: Added warning about Tangsinuo not providing the filter thickness requested by the customer. This is a "Best" list for some basic gear. Be sure to see the 2nd post for the UV-pass filters. UVP and its Owner/Admins have no monetary affiliation with any vendor. UVP and its Owner/Admins are "gear neutral". Use what you love using! All links are for your information only and do not constitute a vendor recommendation. Search around for the best prices. The recommendations here are for basic beginner gear. Your needs might be more specific or more advanced. If so, please consult the Stickies and check recent forum discussions. Note that there are NO camera or lens recommendations!! Everybody including their 3rd cousin's brother-in-law's mother's best friend has an opinion about UV-capable lenses and cameras and those opinions are all different. Try this search tag to find recent forum discussions: Camera Search Tag. In reflected UV photography, just as in Visible photography, we can say that better sensors do give better files. However, artistry in UV photography can be accomplished with any UV gear. SHOPPING WARNING: If you find some name-brand gear online at a price which seems too good to be true, then it is probably some imitation being passed off as authentic. Please shop only at a reputable online store. As one example, Alibaba was recently selling fake Zeiss T* UV-blocking filters. SAFETY Best UV Protection Glasses or Goggles: Yes, UV light is dangerous! Ever gotten a sunburn? Ever had snow-blindness? And UV damage to eyes & skin is cumulative. Look for at least 99% blockage and wrap-around protection in the safety glasses you choose. Here are two options. McMaster-Carr 99.9% UV Protection Rating The linked page shows wraparounds, panoramics which fit around the temple, and ventilated goggles. Prices range from $9 to $30. Here is a specific link for yellow or orange tinted goggles: https://www.mcmaster.com/eye-protectors/lens-color~yellow/lens-color~orange/uv-protection-rating~99-0-/ Here is a specific link for ventilated goggles: https://www.mcmaster.com/eye-protectors/lens-color~yellow/lens-color~orange/uv-protection-rating~99-0-/lens-style~panoramic/lens-properties~ventilated/ UVEX also makes very good protective glasses/goggles. The link is to the manufacturer's website which has scads of info about sports & safety glasses. To buy UVEX goggles it's probably best to google around for the best deal on Amazon or other websites. LIGHTING Best UV Illumination: SUNLIGHT !! "-) There's more UV in Sunlight at high altitudes. There's more UV in Sunlight in the middle of the day. There's more UV in Sunlight in summer. So, mountain top at high noon in July and you're good to go! However, if Sunlight is missing at sea level in the early morning in December, then see the next entry. Next Best UV Illumination: UV-Flash The Xenon flash tube must be uncoated. The Canon 199A is a current UVP favorite for modding into a UV-flash. But there are other possibilities. Use the next link. Lighting TAG Search Click that lighting tag search for further info about UV lighting. There will be info about UV-flashes in there somewhere. Ordinary Xenon flashes can be modified (DIY) with filters to pass only UV light. **WARNING** Please remember that flash units have murderous capacitors, so do not fry yourself dead by wonking around in the wrong part of the flash unit while changing the filtration. Mod a flash unit at your own risk!! Best Basic 365-nm UV-Led Torch: Convoy S2+ UV with Nichia Chip A NOTE: Recently the no-name "Nemo" torch has been more popular with the UVP Membership. Nemo search on UVP. Nemo search on Google. A UV-Led torch is used to supply light for focus illumination on the subject while focusing through Live View, or inducing Visible or IR fluorescence in a dark room, or light-painting a reflected UV subject during a long exposure. In the past Nichia was considered the best 365nm UV-Led Chip maker. But I don't think you should worry too much about either the brand or the grade of UV-Led chip because we are looking mostly for enough output (wattage). You might need two torches depending on how you make use of them. If you can find info about the UV-Led torch chip you are considering buying, look for an A grade UV-Led for best results. TORCH NOTE 1: The Convoy S2+ Nichia A torches are well-made, well regarded and meet stated specifications. If you want something less expensive, then you can take your chances with the unbranded UV torches sold on Ebay. Many of these do not meet their stated specifications. Please check the recent forum discussions for advice on unbranded torches! TORCH NOTE 2: That third use of a UV torch there in the bullet list? Let me point out the following: it's not easy to make a reflected UV photograph using only a UV torch. Exposures are long and results are noisy. The best reflected UV photos are made in strong sunlight or using a Xenon flash with a UV-pass filter. Sunlight and UV-flash produce more false color due to the wider range of UV. Best UV Light for Beginners, Intermediates and Advanced: UVA and UVB ONLY!! As for UVC, we say NO, just NO. UVC is too dangerous. And it is very difficult to find the filters, lenses and cameras which can record below 300 nm. There's scarcely any UVC light in sunlight anyway. So where would you find illumination? You don't want to even go near those 254 nm sanitizing bulbs which will break your DNA. Frankly, IMHO, what I've seen so far in UVC photography is not particularly impressive anyway. UVC is not where the beauty of reflected UV photography lies. It just isn't. If you must play with UVC, please remember that you have been warned by UltravioletPhotography.com NOT to do this. UltravioletPhotography.com cannot and will not accept any liability for damages you may incur from UVC light. Best Filter for Basic 365-nm UV-Led Torch: Hoya U-340 x 2.0 mm LINK to Transmission Chart LEDs have a fairly narrow output, but using this filter on your torch will ensure there is no violet/blue visible contamination when the torch is being used for inducing visible fluorescence. You do not need to filter your torch for non-fluorescent work. FILTERS Best UV/IR-Blocker for making Visible Light photos with Full-Spectrum Camera There will be opportunities to use your full-spectrum conversion in visible light. So replacing the removed internal UV/IR blocking will be necessary. Kolari Hot Mirror Pro 2 Best, IMHO. Link to UV/IR-Blocker tests Kolari's newest UV/IR-Blocker has a transmission curve which matches the transmission curves of most cameras internal filtration. White balance in-camera should give you good color. Any small deviations are easily tweaked in an app or by using a color correction profile. OR Schott BG38 x 2.0mm OR B+W 038 + [Longpass UV-Blocker] Filter stacks like this are somewhat more prone to flare & ghosting in backlit scenarios. Your choices for the longpass UV-Blocking component are: Schott GG400 or Schott GG420 Most camera makers' internal UV-cut filtration begins somewhere between 400-420 nm. Filter stacks work better if one of the components has AR-coating. That costs more though. Zeiss T* UV Filter This filter is regarded by many as the best UV blocker. It is AR-coated and cuts UV very well starting between 400-410 nm. Best IR-Blocker for making Reflected-UV photos with Full-Spectrum Camera Stack one of these over your UV-pass filter for extra protection against IR contamination. Schott S8612 x 2.0 mm LINK to IR-Blocker Transmission Charts for 2.0 mm Depending on the thickness of your dual bandpass filter, you might find that a thinner S8612 will suffice. But a 2.0 is almost universally useful and is the best thickness for your first purchase. Try to get one with AR coating. Recently S8612 has been difficult to find. OR Schott BG39 x 2.0 mm OR B+W 039 S8612 has become difficult to find, so look for this next best IR-blocker for working in UV with a full-spectrum camera. Best Chinese ZWB and Other Filters: Tangsinuo Technology This currently reputable vendor recommendation is subject to change. UPDATE 9 April 2024: Recently a UVP member has reported that the thicknesses of filters received from Tangsinuo have not matched the requested thicknesses in the order. For example, one filter was .5 mm thinner than requested. Please INSIST when ordering that your requested thickness is supplied or else you will give Tangsinuo a bad review and file a complaint with Ebay. LINK to Review by JMC Please remember that Chinese manufacturing is not currently subject to the same standards which apply elsewhere. Striations, pits and visible leakage have been seen with some of the Ebay Chinese filter purchases. And some of the filters don't quite match the expected transmission in either peaks or rate. But these equivalents of UV dual bandpass filters and BG filters are very much less expensive than the high quality Schott or Hoya glass, so most beginners use Chinese filters to get started. FILTERS is continued in the next post.

First a UVC warning - UVC is dangerous. The author does not recommend trying to replicate these experiments without knowledge and use of the proper safety equipment and procedures. This thread will cover information about an experiment I'm doing which is at an early stage. With my UV microscope I've been using it at 365nm and 313nm and it has been fine with those wavelengths. When I built it, I made sure components were used which would be usable down to 250nm, and perhaps even a little lower. However at that time, I didn't have a suitable light source, and my filtering and even camera choice made any experiments down at 254nm impractical to attempt. A couple of weeks ago I was chatting with a couple of folks on here, to try and get some advice with regards to a UVC LED source I was thinking of buying. I was steered away from my original idea, and towards trying a 3W UVC lamp as it was potentially small enough to use with my microscope. Thanks to Andy and David for taking the time to discuss things with me. The aim of this thread is to provide a bit of an update to what came of those discussions, and share some very early results of UVC microscopy at 254nm. The light source is a 3W low pressure mercury lamp source from China over ebay, cost about 8USD. I ended up mounting this in a spare Olympus lamp holder I had, after removing the internal glass lens and IR blocking filters. As result the 3W lamp was used as is, no collimating, no filtering, no anything. The camera I used was a MaxMax monchrome converted Nikon d850 with a fused silica window. I have used this before for UVC photography so know it is sensitive that far down. Filter was a 254nm one from a Sirchie forensics cameras. Again I have used this before for UVC photography. Some images of the setup etc. First, the lamp spectrum, at a distance of 10cm from the side of the lamp. The microscope with the lamp in place and switched on. And a first sample image using the diatom slide (fused silica/quartz for the slide and coverslip) using a 10x Zeiss Ultrafluar objective. I also got an image with a Schott WG305 2mm thick filter in place, the idea being to let through everything which isn't UVC (i.e. leakage from the 254nm filter). Looking at the RAW files for both images, I reckon about 90% of the image above is from the UVC and 10% of contribution of other wavelengths. This just goes to show how insensitive the camera is down there. This is very, very early days, and the method presents some very extreme challenges (in addition to safety). I need a way of focusing and collimating the light source better, as I am losing a lot at the moment. I need another 254nm filter to trying and better isolate that region. As with my 313nm work, I'd probably stack them together for better blocking. Live view focusing is currently not possible with the camera, as there is just so little sensitivity, so focusing is guesswork and trial and error. The image above was 30s at ISO1000, so it is not a fast process. I've got some 265nm LEDs on the way, so will check against the 3W low pressure mercury lamp to see how much light they are producing - maybe they will be better. Personally, I doubt they will be better, but only testing will tell. This is a bit of an unfunded side project for me, more scientific curiosity to see if it can be done than anything else (after all, the initial UV microscopy pioneers back in the late 1900s and early 20th century were doing this with plate cameras), and will update as and when I have new data/images to share. And again - just to emphasize, this is UVC work, do not try this at home.......

UV SAFETY] UV-C Light Is Dangerous NEVER look at a UV-C light. NEVER let UV-C light hit your skin or eyes directly or by reflection. UV-C light can cause: severe burns of the eyes and the skin, and DNA damage from broken chromosomes. When working with UV-C illumination, you MUST: cover up completely, wear head & eye protection, and have strong ventilation. It is hard to find lenses made specifically for UV-C. But for some years, 254nm was the main wavelength used for printing transistor and microprocessor circuits on silicon wafers. These were made to have perfectly flat fields, large apertures in order to avoid diffraction, and extremely high resolution. To achieve the highest possible resolution, these lenses are optimized for a single wavelength. These lenses could cost hundreds of thousands of dollars (their more modern replacements cost millions). They were among the most perfect lenses of their time, and they could use very exotic materials. Sometimes these come up for sale on eBay or industrial salvage sites. That's how I got this Tamarack Scientific 254nm 1/5x reduction lens. The lens alone weights 10kg!

[UV SAFETY] UV-C Light Is Dangerous NEVER look at a UV-C light. NEVER let UV-C light hit your skin or eyes directly or by reflection. UV-C light can cause: severe burns of the eyes and the skin, and DNA damage from broken chromosomes. When working with UV-C illumination, you MUST: cover up completely, wear head & eye protection, and have strong ventilation. UVIVF, UltraViolet Induced Visible Fluorescence, with many UVA, UVB, UVC, LED lights & Far UVC Excimer lights. I now have a collection of UV LED lights, 365nm, 340nm, 310nm, 395nm, 375nm, 365nm, 255nm & 222nm Excimer Far UVC lights. I have been developing my Macro set-up & light stands. These are taken with an unconverted Sigma fp camera with a Sigma 70mm macro lens. The rock/mineral sample is one in my collection from the Puttapa Zinc Mine, South Australia, & contains willemite, calcite & smithsonite, plus others. I have tried to process these all in a simple & similar way. I have adjusted the shutter speed & aperture to maximise the dynamic range in the histogram to fill it from left to right. Processing has been minimal to white balance on the black cap the rock is sitting on & sharpened in Topaz Sharpen AI. First in Visible Light 400nm - 700nm. Far UVC 222nm Excimer Light, Induced Visible Fluorescence, safer to use. Protect eyes, face & all skin. UVC 255nm LED, Induced Visible Fluorescence, knowledge of the safe handling this light is needed. Protect eyes, face & all skin. UVC 265nm LED, Induced Visible Fluorescence, knowledge of the safe handling this light is needed. Protect eyes, face & all skin. UVC 275nm LED, Induced Visible Fluorescence, knowledge of the safe handling this light is needed. Protect eyes, face & all skin. UVB 295nm LED, Induced Visible Fluorescence, knowledge of the safe handling this light is needed. Protect eyes, face & all skin. UVB 310nm LED, Induced Visible Fluorescence, knowledge of the safe handling this light is needed. Protect eyes, face & all skin. UVA 340nm LED, Induced Visible Fluorescence, knowledge of the safe handling this light is needed. UVA 365nm LED, Induced Visible Fluorescence, knowledge of the safe handling this light is needed.

[UV SAFETY] UV-C Light Is Dangerous NEVER look at a UV-C light. NEVER let UV-C light hit your skin or eyes directly or by reflection. UV-C light can cause: severe burns of the eyes and the skin, and DNA damage from broken chromosomes. When working with UV-C illumination, you MUST: cover up completely, wear head & eye protection, and have strong ventilation. Fluorescent Minerals is like a Box of Chocolates, You never know what you are going to get ! Sodalite is a popular mineral with the Fluorescent Mineral collectors as it displays well under Black Light. Here is some Sodalite in Eight UV wavelengths from Far UVC 222nm to 365nm & one in Visible light. Sodalite in Visible Light 400nm - 700nm. Sodalite in Far UVC 222nm Excimer Light, Induced Visible Fluorescence, safer to use. Protect eyes, face & all skin. Sodalite in UVC 255nm LED, Induced Visible Fluorescence, knowledge of the safe handling this light is needed. Protect eyes, face & all skin. Sodalite in UVC 265nm LED, Induced Visible Fluorescence, knowledge of the safe handling this light is needed. Protect eyes, face & all skin. Sodalite in UVC 275nm LED, Induced Visible Fluorescence, knowledge of the safe handling this light is needed. Protect eyes, face & all skin. Sodalite in UVB 295nm LED, Induced Visible Fluorescence, knowledge of the safe handling this light is needed. Protect eyes, face & all skin. Sodalite in UVB 310nm LED, Induced Visible Fluorescence, knowledge of the safe handling this light is needed. Protect eyes, face & all skin. Sodalite in UVA 340nm LED, Induced Visible Fluorescence, knowledge of the safe handling this light is needed. Sodalite in UVA 365nm LED, Induced Visible Fluorescence, knowledge of the safe handling this light is needed.

Well this may not be a surprise to most here. But UVC is dangerous and certain "cleaning" devices are outputting enough UVC to burn your skin and eyes. https://www.fda.gov/medical-devices/do-not-use-ultraviolet-uv-wands-give-unsafe-levels-radiation-fda-safety-communication

Just ordered two Nemo UV flashlights. Purchased a cheap pair of UV protection goggles. The only model available in my small town. Wouldn't mind buying a better set. Any brand /model recommendations? Is there an easy way to test the current goggles? Thanks, Doug A

UltravioletPhotography.com does not support using UV-C lighting for UV photography. UltravioletPhotography.com is not responsible for any damage you might do to yourself or others when using UV-C illumination. We have prominently pinned this warning and require a reference to it in any UV-C topic. NEVER look at a UV-C light. NEVER let UV-C light hit your skin or eyes directly or by reflection. UV-C light can cause severe burns of the eyes and the skin, and damaged DNA from broken chromosomes. .When working with UV-C illumination you MUST cover up completely! 100% cotton clothing (laboratory grade, tight weave) socks, pants, long-sleeved shirt, GLOVES no polyester UV protective face shield which also has head and neck covering. .When working with UV-C illumination you MUST have strong ventilation! UV-C lights produce OZONE which builds up very quickly. Even so-called "ozone-free" germicidal bulbs still produce some ozone. The United States Food & Drug Administration has an excellent write-up about UV-C within the context of killing the Covid-19 virus. The information is relevant for any use of UV-C lighting. UV Lights and Lamps: Ultraviolet-C Radiation, Disinfection and Coronavirus Also from the US FDA is the following informative article: Ultraviolet (UV) Radiation 22 July 2021 UltravioletPhotography.com is not responsible for any injuries resulting from the use of Ultraviolet light of any type. Any UVP member using UV illumination from any source does so at their own risk. We have prominently pinned UV safety warnings. The first linked topic below has extensive links to other info about UV light and its dangers. [uV SAFETY] UV and Your Eyes :: UV Safety Reference [uV SAFETY] Xenon Strobe and UV-Flash Safety Hints Any topics discussing UV-C are required to reference this UV-C safety warning. [UV SAFETY] UV-C Light Is Dangerous: READ THAT NEVER look at a UV-C light. NEVER let UV-C light hit your skin or eyes directly or by reflection. UV-C light can cause: severe burns eyes/skin and DNA damage from broken chromosomes. When working with UV-C illumination, you MUST: cover up completely and have strong ventilation.

Please let me know if this is sufficient. It is taken from a couple of Dabateman's warnings. He is a laboratory scientist and knows how to take sufficient precautions when dealing with UVC lights. UVC light can cause blindness and damage DNA. NEVER look at a UVC light or let it hit your skin. To be near UVC lights you MUST wear 100% cotton clothing (laboratory grade tight weave, no polyester), and wear a UV protective face shield which also has a head and neck covering. Socks, pants, long-sleeved shirt, UV-blocking face shield with head & neck shrouding and gloves. UVC lights produce OZONE which builds up very quickly. Even so-called "ozone-free" germicidal bulbs still produce some ozone. So UVC light must be used only in a remote controlled, professionally vented room well away from pets, kids, people and humidity.

BLB Fluorescent Bulbs vs BL Fluorescent Bulbs .....must finish later......

UV SAFETY] UV-C Light Is Dangerous NEVER look at a UV-C light. NEVER let UV-C light hit your skin or eyes directly or by reflection. UV-C light can cause: severe burns of the eyes and the skin, and DNA damage from broken chromosomes. When working with UV-C illumination, you MUST: cover up completely, wear head & eye protection, and have strong ventilation. Hello there. It's been a long time since I posted. Life got in the way. But this video just came in and it is honestly a little bit concerning. Brainiac75 tests the output of halogen lamps and finds out they emit a small amount of UVC. I have an unfiltered 125w spotlight that I have used a few times as a lightsource and I am wondering what the implications of this are. So I was browsing AliExpress for fun last night, and I ran into this. https://www.aliexpress.com/item/4000805185239.html?spm=a2g0s.8937460.0.0.2f5b2e0eAat3SH It's extremely cheap and if you would have shown me this and asked me what it is, I would say it looks like an incandescent lightbulb judging off of the looks. But it's not? I have no idea what this could be, is it simply filled with mercury vapor and there's a current jumping between the two electrodes? Also they sell a "With Ozone" and "No Ozone" versions which confuses me further. I wont buy it since I don't own any UVC safety gear, but I'm still curious.

If I had to make up a tag for this topic, I would call it "UV surprise"... This is a great example of how our cameras can, very literally, see the invisible. I have several pairs of polycarbonate goggles. They are all the same, if we don't consider brands etc. They all block UV, as expected. But one of them is special: Months ago, with my old camera, I noticed something odd. I was taking some UV photos of one pair in particular, and saw something that didn't make any sense: The right temple is... transparent? I thought it could be a reflection, but still I couldn't wrap my mind around it. Then, when I was taking the first photos with my new (current) camera, of a random pair of goggles (the same as the previous one by coincidence), I did notice, quite clearly, that the right temple actually is transparent! And the left one is opaque! They are clearly made of two different plastics. How is this possible? The first photos taken with the new camera aren't that good, I was still learning how to use the camera, the lens etc., so today I took some good ones to show this better: Both images taken at f/22, ISO 100, and 45.3 seconds in BULB mode. I took also some photos under UV LEDs, both 365 and 340 nm, and the results are the same. The temples to me look exactly the same with the naked eye, there is one which, maybe, looks a tiny tiny bit bluer, but can be just my imagination. Under UV torches I also noticed the transparent temple fluoresces some, the other one much less. You never know until you see the invisible!

Warning UV-C should never be taken lightly. Wear protective gear and cover up your skin. You will damage your skin and can get seriously hurt yourself. I was able to convince Dan at MaxMax (LDP) to convert a Raspberry Pi HQ camera to Monochrome. Its an exciting camera and he now has them for sale. You can see them here: https://maxmax.com/maincamerapage/monochrome-cameras/raspeberry-pi-cameras/raspberry-pi-hq-12mp Mine arrived today and the first thing I tested was my 254nm light with 25mm single fused silica element with the 254.3bp25 filter on front. This sensor is very sensitive to UV-C!!!!! Direct from camera Jpeg, resized for posting. ISO equivalent 320, F4 (cut a 6mm disc behind the lens), 1/16 second shutter speed! Direct from camera Jpeg, resized for posting. ISO equivalent 320, F4 (cut a 6mm disc behind the lens), 1/16 second shutter speed! Using DCraw for Raspberry Pi HQ camera with -d -6 -T switches and resizing for here ISO 160, 1/16, F2 (cut 1/2 inch hole behind lens): I just missed the focus on where I want for that one. This sensor is fast and can capture movies. So for under $1000, UV-C imaging at 12 Mpixels is in our hands (my hands). This should be fun. Its only Monochrome but still, great.

Warning. Do not try UVC (254nm) photography unless you take the proper precautions. Wear 100% cotton cloths to cover your body, EYE PROTECTION is MANDATORY!!! Ok still excited. With Jonathan's success with Sony sensor I thought I would test out my newly converted Olympus EM5mk2 by Kolari, which has fused silica on the sensor inplace of the UV/IR cut filter. These images are with my custom 39mm single fused silica lens element and 254pb25 filter. I might test the UAT to see how it performs. First to scare you a visible reference of some of the mold I need to image: Then same jar with same 39mm lens, at the same closed down aperture, lens moved forward on rail as I roughly know where the focus shifts to, ISO 6400, 10 seconds, the aperture might be close to F22: These are my UV beads with 39mm lens open, ISO 1600, 1/2 second exposure, F1: These are the same UV beads with 39mm lens slightly closed down ISO 1600 1 second: This lens is a best case as single element and has massive focus shift to select out specific wavelengths. Its good in that its really close for 254nm, and further back for each additional wavelength. But bad in that it would be very hard to use it for UVC, UVB, UVA tri color image. But for IR I need to move it more than a foot back. These results are much better than my full spectrum EM1 with UAT as I couldn't focus that in live view, even at maximum ISO. The EM5mk2 allows for focusing in live view with this lens at least. So the Sony sensor in the EM5mk2 is more sensitive to UV than the Panasonic sensor in my EM1. I wouldn't have guessed that, actually didn't guess that and thus the test. I didn't white balance these, just used the standard WB I have for UVA. The base in the beads shot should be white.

In the post at https://www.ultravio...-your-rocks-of/ I showed results of fluorescence exhibited by some rock samples using both UV (Nemo torch) and visible excitation. The subsequent comments raised the idea of using a low-cost 254nm UVC lamp to see if that gave different output. So I got myself one of these rom China: https://www.ebay.co....872.m2749.l2649 . A few weeks later it arrived – but the filter was chipped along the edge and leaking light, and the filter housing wouldn’t close properly. The supplier said something like “Yes, happens all the time. But it will be OK.” Anyway, they sent me a new filter, which I cemented to the outside of the housing, and off we go. Health warning: UVC is dangerous. There’s plenty of advice on the forum about protecting yourself using glasses, cotton clothing, etc. In addition I took two precautions: Adapted the lamp to run off external power and used the cameras on WiFi remote control, to let me operate from a different room. As the lamp needed several minutes to fully “warm up” it was impracticable to turn the lamp off between each shot. So I made a simple cardboard sleeve to slide over the lamp so I could work nearby to set up the camera and target. UV and IR Colour Images: In UV and IR false-colour images below, the following colour assignments have been used: Red Channel UV: 380nm Green Channel UV: 345nm Blue Channel UV: 315nm Red Channel IR: 1000nm Green Channel IR: 850nm Blue Channel IR: 750nm The lamp: It became clear that the lamp and its filter leak a lot of non-254nm wavelengths. I tried to get fluorescence output at UVA wavelengths, but the images were almost entirely like reflected light images, although there was a hint of fluorescence output – results later. More surprisingly, there was a lot of IR leakage too. The IR output results looked totally like reflected light images with no hint of fluorescence. I have not bothered to post any results here. Fortunately the visible output was reasonably good – but the fluorescence is being excited by multiple wavelengths, not pure 254nm. The following images give an idea of the leakage. In each case, the upper image used exposure similar to that used to make the fluorescence images, and the lower image is at a lower exposure to show the colour of the leakage. The colour images were WB-ed for sunlight. Visible Output: UV Output: IR Output: I also used one of Stefano’s tests (see https://www.ultravio...-265-nm-uvc-led ) to judge how strong the 254nm lamp output was. Pure 254nm (or at least below about 320nm) would render the magnifying glass as pure black. My conclusion is that there is a lot of 254nm, but there are longer wavelengths as well. In each case, the upper image is against paper (fluorescing) and the lower image against PTFE (probably non-fluorescing). Visible: UV (lower image's exposure was 7.5x upper image's exposure): IR: Results 254nm-Induced Visible Fluorescence When looking at output in the visible range, some targets look the same whether excited using the Nemo torch or the 254nm lamp. But in some cases there was some additional green fluorescence. The top images are normal visible images, the middle images are UVIVF made using the Nemo torch, and the lower images are UVIVF made using the 254nm lamp. Rainbow Flourite I assume the fluorite is the main bulk of the sample, and the white/green areas are something else adhering to the fluorite. So the fluorite fluoresces consistently blue, but the “something else” shows green under 254nm. Group 3 What’s really noticeable here is the appearance of green in the Aragonite and yellow calcite, and the whitish fluorescence in the blue calcite (bottom left). 254nm-Induced UVA Fluorescence: As mentioned above, these images are largely reflected-UV images, but we can see some fluorescence. The predominance of green indicates fluorescence output around 345nm. The top image is a normal visible image, the middle image is a “normal” tri-colour reflected UV image, and the lower image is UV-Induced UVA Fluorscence made using the 254nm lamp. In all cases, WB was against the PTFE background. Rainbow Flourite Pink Aragonite Group 1

Ok, disclaimer first - UVC is extremely dangerous, please do not attempt to use it without fully understanding the risks involved. Background to this work. I've been seeing everyone playing around with UVC, and had assumed that there was little point even trying it with the cameras I've got. A few weeks ago I bought a couple of 254nm 8w tubes to fit my UVP lamp, and today thought I'd just give it a go with my monochrome Nikon d850 (which has a quartz coverglass instead of the usual WG280) and Rayfact 105mm UV lens. Setup. 2x8W 254nm tubes in a UVP lamp, no filter on the lamp. Subject a vase with a couple of feathers in it, and a 20% diffuse reflectance standard. Filters, a 254nm bandpass filter from the Sirchie forensics camera, WG305 2mm and WG295 3mm. Camera, monochrome converted Nikon d850 with fused silica window from MaxMax. Lens, Rayfact 105mm UV lens. Settings, ISO400, f8, 30s exposure for the UV images. Whitebalanced in Darktable and reduced in size in XnConvert. Images shown with reduced resolution, but full frame. Firstly, image with visible light. Now with 254nm lamp and the 254nm bandpass filter only. So, with the 254nm lamp and bandpass filter I get an image (which I wasn't expecting to be honest), and because the glass of the vase is opaque at least some of this is UVB or even UVC. Next I tried putting a couple of different longpass filters in front of the 254nm filter. The aim here to try and block what the 254nm filter should be letting through, while letting through the out of band areas of the 254nm filter. I did this to check for leaks. With the WG305 2mm in front of the 254nm filter. And with the WG295nm 3mm filter in front of the 254nm filter. Both the WG305 and WG295 filters resulted in a reduction in the image brightness, but they did not eliminate the image, which suggests to me that there are some leaks in the 254nm filter in the longer wavelength regions. But it also tells me that most of the image is coming from the UVC region, which I did not expect. I must admit, I hadn't realised when I chose these two long pass filters that the 254nm one had such a long tail on it. Perhaps in hindsight a longer long pass filter would have been a better option. EDIT - Although looking as closely as I can at those WG images, the vase looks dark which would suggest leakage in the UVB/C region, so perhaps it is coming from the overlap region? More work needed there I think. Something to consider is the filter transmission spectra and the light irradiance spectra, which are given below (full range and then zoomed in on the UV region). Yes, there is some overlap between the 254nm filters and the WG ones in that 280nm to 300nm region, but it occurs at a region where the light is not really emitting anything, which makes me think that the 254nm images are really driven by that big 254nm line in the lamp. It also tells me that even good filters for UVC run the risk of letting enough light through in the out of band regions to contaminate the image - OD4 is no longer good enough, even with a light source like this with a really strong 254nm peak. I learned something new today - don't make assumptions about cameras capabilities before testing them. Sorry for any typo's, I'll go back and proof read when I have a minute.

Could I not try the green banana test with my LEDs? Of course not! It is a must with UVC. So, I took a greenish banana (not really green, but it still has some green) to test this. Green bananas work better than yellow ones, for some reason. It is surely due to chemicals present only in unripe bananas, as this is almost surely a chemical reaction caused by the energetic UVC photons. For testing, I chose the green areas of the banana. For both tests the LED was run current-limited at 50 mA without an heatsink. The output power, if it is a third of the maximum, is around 3 mW. First, I tried with the LED at some distance from the banana, and a plastic thing that blocks UVC to cast a shadow. I irradiated like this for one hour: After one hour, I turned off the LED and took a look. There was no visible discoloration. Since this was probably due to the very low intensity, I placed the LED much closer, and irradiated for one hour again: And, after waiting for another hour, I took a look, and this time it was a success! It must also be noted that this browning/discoloration effect sometimes takes hours or days to develop AFTER the initial irradiation. Kind of like sunburns. So I will update you tomorrow if I find some differences.

[UV SAFETY] UV-C Light Is Dangerous NEVER look at a UV-C light. NEVER let UV-C light hit your skin or eyes directly or by reflection. UV-C light can cause: severe burns of the eyes and the skin, and DNA damage from broken chromosomes. When working with UV-C illumination, you MUST: cover up completely, wear head & eye protection, and have strong ventilation. I'm still waiting to start my trials with using 254nm UV to induce fluorescence. (The lamp has arrived, but the filter was chipped, so awaiting a replacement.) I've taken on board all the advice for personal safety and have a strategy to protect myself. But does anyone know whether 254nm light could be harmful to plants? My wife is not going to be very happy if I kill off her orchids, etc., with my little experiments.

EDITOR'S NOTE 27 Feb 2023 I have returned to all UVC posts and placed a UVC safety prefix in the title and copied the following UVC Safety suggestions at the beginning of the topic. [UV SAFETY] UV-C Light Is Dangerous NEVER look at a UV-C light. NEVER let UV-C light hit your skin or eyes directly or by reflection. UV-C light can cause: severe burns of the eyes and the skin, and DNA damage from broken chromosomes. When working with UV-C illumination, you MUST: cover up completely, wear head & eye protection, and have strong ventilation. Can someone research and list what protection is required for anyone working with UVC? There was some discussion about separating UVC topics into their own board. But the UVC references are so scattered that this probably cannot be done. Given the dangers of playing with UVC, what should I do as the Admin/Editor/Owner?? Post warnings every time UVC is mentioned? Forbid discussion of UVC and any UVC photographs? Start a UVC board for all future posts/discussions? I have to think about the possibility that someone could get hurt playing with UVC and then blame this website. So these are serious questions. Frankly, I never thought anybody would go there given the dangers. But it has happened more than once. So I'm worried. [hr[

Last Edit [22 July 2021: Added links to other pinned UV Safety topics.] Limitation of Liability: UltravioletPhotography.com The material on UltravioletPhotography.com (UVP) may contain inaccuracies and typographical or other errors. UVP makes no representations about the accuracy, reliability, completeness, or timeliness of the material or about the results to be obtained from using the website and/or the material therein. Use of the website and any information contained therein is at your own risk. The material and other content on this website may or may not be periodically updated or revised at any time. These Terms and Conditions of Use shall apply with equal force to any and all such updates or revisions. Your use of any ultraviolet outputting lamp, bulb, flash, LED light or other device is at your own risk. See also: [uV SAFETY] UV-C Light Dangers [uV SAFETY] Xenon Strobe and UV-Flash Safety Hints My main reference from Columbia University is no longer available as of 22 July 2021. However I will let the topic stand because the UV exposure limits are similar to what is found in other sources. Example: https://orm.uottawa.ca/my-safety/em-radiation/uv/exposure-limits UV Eye Damage Question: I would like to photograph someone with their eyes open. It is widely warned that you should not look directly into a UV-flash or UV-LED, however, what if you did? Answer: You might sustain burns or other injuries to the eyes. So please do NOT directly look at a UV-flash or UV-LED or any other source of UV light. UV-blocking eye protection in the form of UV-blocking goggles or face masks is mandatory when using any UV outputting lamp, bulb, flash, LED light or other device. This includes those UV blacklight party lights, also used for fluorescent posters. No one can tell you how many UV-flashes, for example, are "too many" for human eyes because those experiments are not done on human subjects. So, the simple answer is do not flash or shine any UV light into anyone's eyes or expose your own eyes to any source of UV light of any kind. Here is what could potentially happen short-term and long-term. Short term exposure to intense UV causes ultraviolet keratitis, a photochemical injury to the cornea of the eye. Welders call this welder's eye and skiers call it snowblindness. In mild cases, you feel dry, scratchy eyes, some eye pain, sensitivity to light and have reduced vision for a few hours because your cornea is swollen and inflamed. This injury is often referred to as a flash burn or a corneal burn, but it is not thermal in nature even though it feels like it. In severe cases of UV keratitis, there can be corneal ulceration and possible infection. Severe corneal damage might eventually necessitate a corneal transplant (taken from a cadaver). See also: Ultraviolet Keratitis This is a medical monograph by Reed Brozen, MD at Dartmouth Medical School, Dartmouth-Hitchcock Medical Center, Vermont. Corneal Flash Burns Long term exposure to UV from sunlight or other sources causes cumulative damage to the human eye which typically manifests itself as the formation of cataracts. A cataract is a cloudy deposit on or within the eye lens. It is said that sooner or later we all get cataracts. This is why ophthamologists encourage everyone to wear UV-blocking sunglasses when outdoors. Long term exposure to UV in sunlight or from other sources can also cause retinal damage or eye cancers. These links about cataracts and UV are from the US National Institute of Health: Facts about Cataract New research sheds light on how UV rays may contribute to cataract Sources of UV Light Halogen lights, carbon arcs, welding arcs, sunlight, sunlight reflected on snow, sunlight reflected on water, UV-flashes, photo floodlights, sun lamps, tanning beds, UV-LED torches/flashlights, UV-C sanitation devices, UV lamps, UV fluorescent tubes. UV Exposure Recommendations The Columbia University (New York City) monograph Working Safely with Ultraviolet Radiation contains some UV exposure recommendations listed below. Columbia University also notes that in the United States there is no Occupational Safety and Health Administration (OSHA) standard for exposure to ultraviolet light. (OSHA is a federal agency in the US Department of Labor which enforces safety & health laws.) However, the National Institute for Occupational Safety and Health (NIOSH), part of the US Center for Disease Control and Prevention, does make some recommendations. Also, the American Conference of Governmental Industrial Hygienists (ACGIH) has issued Threshold Limit Values (TLVs) for occupational exposure to UV. I have to review notation here so I can keep it straight. watts = W milliwatts = mW microwatts = µW 1W = 103mW = 106µw meters = m centimeters = cm 1m2 = 104cm2 Columbia University Recommendation for UV-A Exposure in Wavelength Range 315-400 nm 10 Watts/m2 for every 1000 seconds. In words, the maximum time for unprotected exposure of skin/eyes to a UV-A irradiance intensity of 10 Watts per square meter should not exceed 1000 seconds. ACGIH Recommendation for UV-A Exposure in Wavelength Range 315-400 nm 1 milliWatt/cm2 for every 1000 seconds In words, the maximum time for unprotected exposure of skin/eyes to a UV-A irradiance intensity of 1 milliWatt per square centimeter should not exceed 1000 seconds. This is (obviously) the same as the preceding Columbia recommendation. 10 Watts/m2 = 1 milliWatt/cm2 1 milliWatt/cm2 for 1000sec == 1000 milliWats/cm2 for 1 second. Thank you, Metric System. Columbia Recommendation for UV-B Exposure in Wavelength Range 200 - 315 nm It appears to me that this range includes some UV-C, yes? The radiant exposure on unprotected eyes and skin within any 8 hour period is limited to values which depend on the wavelength of the radiation. For a broadband source the effective irradiance should be measured or calculated, and the maximum permissible exposure determined from the table below. LEFT: Effective Irradiance (Watts/m2) RIGHT: Maximum Permissible Exposure during an 8 hour period 0.001 8 hours 0.008 1 hour 0.05 10 minutes 0.5 1 minute 3 1 second 30 0.1 second NIOSH Recommendation for UV-C Exposure at Wavelength 254 nm Note that 254 nm is the typical wavelength for UV-C sanitation lights. 100 μW/cm2 for 1 minute In words, the maximum time for unprotected UV-C exposure of skin/eyes to an intensity of 100 microWatts per square centimeter should not exceed 1 minute. When averaged over an eight-hour work day, this value is 0.2 microWatts per square centimeter. Convert: 100 microWatts/cm2 = 0.1 milliWatts/cm2 for 1 minute. Convert: 6 milliWatts/cm2 for 1 second. Obviously, the greater the intensity of the UV-C light source, the shorter the time you are allowed for unprotected exposure. In case this is not hitting home with you, the NIOSH recommendation is telling you that 254 nm UV-C light is extremely dangerous !!! Side Note: There is one incomplete statement in this Columbia U. reference. They say eye damage is from UV-B and UV-C, but it has been recently learned that eye damage also occurs due to oxidative stress from UV-A. See Ultraviolet Keratitis link above. Example: Blak-Ray B-100 AP Lamp From the manufacturer's data, we have that the Blak-Ray B-100 AP lamp with a UV-A range peaking around 365 nm delivers an intensity of 21.7 milliWatts/cm² at 5 cm (about 2 inches) and 8.9 milliWatts/cm² at 25 cm (about 10 inches) distance from the lamp. Various factors affect the actual intensity from such a lamp because of geometry, angles of use, ambient reflections and so on. Nevertheless, we will use those numbers in the following model as a worst-case intensity from a Blak-Ray directly shining on a subject. Given that the Columbia or ACGIH recommendation for UV-A is 1000 milliW/cm2 for 1 second, we can convert to get an exposure time for the Blak-Ray lamp of 1000/8.9 = 112 seconds = 1.87 minutes. (This does make the assumption that the Blak-Ray lamp is only outputting UV-A. The Blak-Ray also outputs some UV-B, but we are ignoring it just to get an estimate.) So, within an 8 hour day you only have a little under 2 minutes without protection to safely(?) experience UV-light from a Blak-Ray B-100 lamp at a distance of 25 cm (10 in) If you have the Blak-Ray shining directly on yourself at the closer distance of 5 cm (2"), then within an 8 hour day you only have a recommended exposure time of 46 seconds. Wear your UV-blocking goggles. And remember that even if you should one time escape obvious UV keratitis of your cornea when looking at UV-light with no eye protection, the UV damage to eyes and skin is cumulative. Eventually UV-light will getcha if you don't protect yourself! And now for a musical interlude: Start at 52 seconds in. UVA-in-Sunlight vs. the Blak-Ray B-100 Lamp Reference: Incoming Sunlight from NASA Earth Observatory All radiation from sunlight is equivalent to an intensity of 1.36 kiloWatts/m2 at the distance from sun to earth. That translates to 136 milliWatts/cm2 at the distance from sun to earth. Convert: 1kW = 106mW (milliWatts) Convert: 1m2 = 104cm2 Of course, this total solar irradiance figure must be modified by reference to geometry, angles, atmosphere and so on when used in any model. Nevertheless, we'll use the 136 milliWatts/cm2 value in the following little estimate as a worst-case kind of intensity from a presumed directly perpendicular ray of sunlight hitting an arm on the ground. At ground level sunlight consists of about 3% UV. So, UV-in-sunlight has an approximate intensity of (136)(.03) = 4.08 milliWatts/cm2 at the distance from sun to earth. From the preceding section, we have that the Blak-Ray lamp has an intensity 8.9 milliWatts/cm2 at a distance of 25 cm (10 in). On a good strong sunny day, put your right arm on the ground and put a Blak-Ray lamp about 25 cm (10 in) away from it. Now put your left arm on the ground. In your current awkward position, the Blak-Ray lamp intensity at 10 inches from your right arm is approximately twice that of the UV-in-sunlight reaching your left arm. 8.9/4.08 = 2.18 Make sure you are wearing your hat and sunglasses when you perform this arm-burning experiment. Your right arm which is 10 inches under that Blak-Ray lamp will be good for about 112 seconds, a little under 2 minutes, before sunburning begins. Your left arm will be in the sunlight for about 245 seconds = 4.08 minutes before it begins to fry. If your Blak-Ray lamp is placed about 5 cm (2 in) inches from your arm, then the Blak-Ray intensity at 2 inches from your arm is approximately 5 times that of the UV-in-sunlight reaching your arm. 21.7/4.08 = 5.3 Please don't mess around with your Blak-Ray lamps by shining them in anybody's eyes or skin, whether human or animal. UV-C @ 254 nm vs. the Blak-Ray Lamp From above, recall the approximations for unprotected exposure lengths. 60 seconds for the 254 nm UV-C source at a distance which produces the intensity 0.1 milliWatts/cm2. 112 seconds for the Blak-Ray Lamp at 25 cm distance with intensity 8.9 milliWatts/cm. Convert UV-C: 0.1milliWatts/cm2 for 60 sec = 6 milliWatts/cm2 for 1 second. Convert Blak-Ray: 8.9 milliWatts/cm2 for 112 sec = 996.8 milliWatts/cm2 for 1 second @ 25cm distance. During a 1 second interval, you could be safely(?) exposed to 166 times more Blak-Ray light than UV-C light. I hope that I have stated that sensibly. The point is that UV-C is quite dangerous when compared to the usual mostly UV-A illumination and it takes very, very little time before UV-C damage begins. I would like to have the numbers for an actual UV-C device to better make the point here. I would also like to have the numbers for one of the 365 nm UV-LEDs so I could make similar comparisons. Whatever I'm missing here (aside from a few UV-fried brain cells), please let me know and I'll correct it. Thanks!

Don says it better than I can. http://donklipstein.com/xesafe.html

We all are familiar with side effects of UV such as development of skin cancer, eye sore, and sunburns. As UV photographers we spend a lot of time outdoors and try to mitigate the risks by dressing sensibly, using sun lotions, and so on. For UV illumination we use UV-enabled flash and sun itself, to name the two most common sources of UV light. Because flash duration is so short it is usual to consider it being fairly low risk in terms of UV side effects. Indoors, Liveview on the moderns cameras hardly work for UV unless a source of UV light is added. I normally use a powerful Nichia UV LED torch as a means of focus assistance, and the same torch is used to produce UV-induced visible fluorescence. As the Nichia is powerful, I always use UV-protective goggles. My big studio flash heads employ uncoated Xenon tubes and thus emits a lot of UV. You are almost guaranteed sore eyes if you don't look away and/or close your eyes when the flash(es) fire. Wearing UV-protective goggles help but cannot eliminate entirely the problem since you may fire long sequences with these flashes when doing focus stacking. Still, UV can hold unpleasant and unexpected surprises. Thus, UV can trrigger photochemical skin and allergy reactions. That is exactly what happened to me today. My medicine regimen recently had Vitamine B3 added to it and I'm ramping up the dosage. Today, this lead to a violent photochemical response when I commenced UV shooting in the morning hours just afte taking the medicines. I worked with a UV photomacrographic stack at 4X magnification to show the conical cell patterns on the petals of Barbarea vulgaris (Brassicaceae). The stack was tricky to accomplish and I had to use my Nichia UV LED a lot in order to fine-tune focus. After about ten minutes my skin started to swell and puff up and I became literally red as a tomato all over my body. Surges of heat waves raced inside, breathing became raspy and I had to use a healthy dose of adrenaline to bring the shock reaction under control. Not something I wish to encounter too frequently. I postponed work on the stack until the afternoon. at which time the attack had ceased and i felt myself returning to normalcy again. This is a small section from the stacked image. Do note how the conical cells not only are associated with the UV-dark patches, but actively enhance them by focusing incident light to add vibrance to the area, plus generate iridescence. I'll post more on these topics in a forthcoming article on conical cell patterns.