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This would be a perfect light if the UV was 365nm. Are there IR torches similar to a Nemo? https://www.ghoststop.com/phasm-light Great, now I want ghost equipment, but don't want to look for . Thanks, Doug A

Hi all, I'm busy building a light source to use to create UVIVF time lapses similar to this example: UVIVF Time lapse - Youtube My main requirement is to achieve a high quality 365nm light for visual fluorescence photography, with enough power to give me flexiblity with exposure settings. I intend to shoot mostly flower time lapses in an enclosed light proof environment. My first build is 5x3Watt led chips from AliExpress with a similarly generic ZWB2 filter which I am still awaiting delivery on. Effieciency is not a major concern for me as long as heat doesn't become a problem. I'm using an actively cooled heatsink and the UV light will only be on for about 20seconds followed by at least 40seconds off. As good quality components (Nichia LED's, Hoya/Schott filters) are at least 10x the price of what I used and I'm trying to keep costs maneagable, my question is where should I invest more if required? Ie would I be better off using the cheap LED's and then trusting a high quality filter to block unwanted wavelengths or rather use Nichia chips with a generic Filter? Or should what I'm doing with work fine? Once I've finished my build I will post some photos of the results.

This is "good to know that such things exist" technical information about Olympus microscopy equipment for imaging at 248 nm. The main purpose of this equipment seems to be imaging of semiconductor wafers at resolutions beyond those possible with VIS light. http://www.olympusca...%20Brochure.pdf Some points gleaned from the brochure: This equipment is for incident axial illumination of specimens, not transmitted illumination. The light source uses an 80 W mercury-xenon bulb. The bulb housing appears to be a standard Olympus part, but in this case it is mounted separately from the microscope and connected to the illumination module by a liquid light guide, probably to eliminate vibration sources. The illumination and imaging module mounts below the tube lens (and therefore eliminates the need to use a special tube lens) but on top of a VIS axial illuminator. Presumably the VIS illuminator must be used with its beam splitter or fluorescence cube out of the imaging path, so simultaneous VIS and UVC illumination is likely not possible (except with VIS emitted by the xenon-mercury bulb). Simultaneous DUV imaging and DUV-excited VIS fluorescence observation and imaging might in principle be possible. The objectives have no cemented elements. We already know one reason for this. An additional reason in this case is that optical cement degrades quickly at these wavelengths. There is virtually no information about the DUV camera.

Ran across this article, from a few years ago, about UV LEDs with quartz lenses. https://www.agc.com/en/news/detail/1196553_2814.html Found it interesting. Thanks, Doug A

What modified flash puts out the most UV? It has to be battery powered portable and relatively easy to modify. Saw @Adrian using 4 Metz plus a small flash in his presentation. He was getting F11 ISO 400 at a few feet away. Amazing. Really enjoyed his presentation. Thanks, Doug A

The following experiment shows by way of example that false colors are possible even with narrow-band illumination using LEDs and that the transition from yellow to blue is not always at the same wavelength. Experiment To investigate, I recorded and compared the spectra of the light sources using a simple method: LED flashlight, metal slit (1.5mm), 1m distance, DVD grating, Baader-U plus 2mm QB21 (to avoid NIR artefacts), f 50mm enlarger lens, Canon 500 D-FS WB in each case on PTFE, identical color profile, which produces yellow and blue false colors with sunlight. LED flashlights: peak values at about 375 nm and 405 nm. Comparison/wavelength calibration: sunlight. RAW conversion: DxO PhotoLab 3, WB sunlight, color rendering "generic" plus "neutral colors, neutral tone, gamma 2.2" Results - Even with narrow-band light sources, yellow tones are shown in the shorter-wave range, blue-violet tones in the longer-wave range. - The position of the color transition from yellow to blue is therefore dependent on the light source. - The color rendering is slightly different even with identical color profiles if the used spectral range is different. Additional comment The Baader-U cuts off at below 400 nm. Accordingly, only the outermost part of the short-wave flank of the emitted light of the 405 nm LED is shown. Since only very little light is emitted here, the exposure time for the 405nm LED is one second - for the 375nm LED it is only 1 / 350s.

Would like to build a "light dome" to place small objects in. Camera and flash would shoot thru hole in roof and the UV light would be bounced around inside. Does aluminum foil reflect UV light? Any other reflective material to try? Thanks, Doug A

While looking for soft UV light for indoor macros, I came across LED-based nail dryers (for UV-curing nail gels and nail polishes). But there are hundreds of products. Some look very promising (365 and 405 nm LEDs combined). There should be no LEDs in the rear area so that a (e.g. black) background can be attached there. The bottom has to be open so that you can hold the whole thing over smaller objects from above. Overall, I would expect a relatively soft illumination from it. Does anyone of you have experience with that? My current UV lamp for disco purposes is not ideal. It has a too small, flat light field and only 365 nm LEDs: https://www.amazon.de/gp/product/B08L76BGGM

Based on a discussion here I was really intrigued by the graph shown for silver with the strong dip in reflectance around 320nm. I ordered a sheet of silver leaf from ebay (edible silver leaf and it was about 2GBP delivered) and decided to test it. Silver leaf was mounted on cardboard using double sided tape. Images done with my Monochrome converted Nikon d850m and Rayfact 105mm lens. f11 and ISO400 apart from the 254nm image (which was f11 and ISO6400). Light source was a Hamamatsu LC8 200W xenon lamp, but for the 254nm image I used a 4W UVP filtered lamp. I included a 99% Spectralon diffuse reflectance standard in each image and exposure time was adjusted to keep that as constant as possible for all the images. Images cropped and resized, but no further modifications. Visible - LC8 light and room light, Baader UV/IR cut filter 390nm to 340nm - Thorlabs 10nm bandpass filter, Hamamatsu LC8 Xenon lamp 330nm to 310nm - Edmund Optics 10nm bandpass filter, Hamamatsu LC8 Xenon lamp 300nm - Edmund optics 10nm bandpass filter and Hoya U-340 4mm as the EO filter leaks light above about 600nm, Hamamatsu LC8 Xenon lamp 254nm - Sirchie 253.7nm filter, UVP 4W 254nm lamp Here's the images. The reflectance of the silver leaf does indeed drop sharply at around 320nm. I recorded the RAW files too, and extracted the channel responses for the Spectralon and the silver leaf. Ratioing the silver leaf against the spectralon gave an interesting graph which closely matched the behaviour shared in the original thread (down to 300nm at least). Simple experiment, but took a while to setup. One of the images (the 360nm one) is a bit blurry, which I didn't noticed until I was processing the images. Also some of the dichroic filters show some evidence of light bouncing around between the layers (see the highlights on the 340nm one especially). Am I 100% confident with the 254nm image being 254nm and not leaks? Yes, pretty much as I've tested this filter before, but I suppose being ultra-picky that is the image and data I am least confident with as it doesn't match the published graph.

For various purposes I was looking for a (low-cost) color card for the UV-A range. The question arises because I don't have beautiful flowers all year round. So I looked for materials that appear colored in the UV image. Many plastic samples appear purple, so they prefer to reflect longer-wave UV light. Some textiles appear yellowish or greenish, especially those that appear yellow and orange in the VIS light. Apparently they prefer to reflect shorter-wave UV. I glued a few samples to a piece of plywood along with a piece of PTFE and a piece of black leather (seems to be black in all wavelengths). Here are a few photos (unfortunately not in the sunlight, as the cloud cover is currently too thick): 1. Canon 500D-FS, enlarger lens, Osram Lumilux deLuxe 950 and white balance against the good old Kodak Graycard. 2. Canon 500D-FS, enlarger lens, Baader-U with a QB21, Xenon lamp (Eprom-Eraser ZAX Quick-E II) and white balance against sunlight. First image native, second image color-enhanced. 3. Canon 500D-FS, enlarger lens, Baader-U with a QB21, 370 nm LED with UG-1. First picture with white balance against sunlight - everything appears yellow here. Second picture with white balance against PTFE - everything appears nearly achromatic here. Sure, the light source is also pretty "monochromatic". But a slight color differentiation can still be seen on closer inspection... Note: Nice how you can see the glue residue in the UV. Question to all Who has discovered materials that only reflect in deep UV-A (appear as pure green)? Klaus Schmitt reported on a Zinnia species (https://photographyoftheinvisibleworld.blogspot.com/2015/07/mexican-zinnia-zinnia-haagenea-in-deep.html). But I am interested in a permanent substance (mineral, pigment, polymer, ...). .

Living less than 500 foot above sea level, I'm convinced electronic flash is needed. Last year I bought some Pentax AF540 FGZ shoe mount flashes. One was thrown in because it was missing the pull out white bounce card and flip down wide-angle diffusion panel. Now, with my help, it's missing the front Fresnel lens. I've had different recommendations for filtering. One said put 6mm of Chinese ZWB-1 on the flash. Another is using Hoya U340 and Midopt BP 365 camera filters. As a quick experiment, I borrowed the ZWB-1 filters out of the two Nemo torches. This gives me 4mm on the flash. With the Pentax K1 Full Spectrum, original metal body Nikon EL-Nikkor 135mm (standard ZWB-1/BG39 filter stack) on Pentax bellows, the pictures don't look bad. I'm using the same custom white balance set for Ioriginal 35mm lens. Flash looks fairly similar to daylight. Same setup on Ioriginal 35 lens has a little bit of a yellowish tint. So what filters are recommended for a UV flash? Thanks, Doug A

I recently bought a Godox AD200 electronic flash. This is a battery-operated unit somewhat intermediate between a speedlight and a studio strobe. It is rated at 200 Ws, which is at the low end of studio strobes, and in practical use it proves to be about twice as powerful as some of the largest all-in-one speedlights. It is intermediate also in weight, being slightly less than 1 Kg, and differs from earlier models of similar capabilities (e.g. Godox AD360, Quantum models) in that it is a modular but all-in-one unit. In particular, it needs no external battery or external power pack. The head is also modular, with a speedlight-style head, a bare-bulb head and a LED head for continuous illumination so far available. Another peculiarity is that the preferred mode of triggering is with a dedicated 2.4 GHz radio master that fits on the hot shoe of the camera. With Canon, Nikon, Sony, Fuji and, more recently, Olympus/Panasonic Micro 4/3 cameras, TTL operation is achieved. This unit is interesting to me on several accounts. One is TTL operation and relatively high power in an all-in-one, relatively lightweight and relatively cheap unit. Another is the potential of converting one head to UV, while still being able to use the unit for normal photography (with non-modified heads). If it works, it is going to be my first TTL UV-enabled flash. I should be able to publish a detailed review of this model on my web site in a few days, dealing only with use in VIS photography (spoiler alert: it works very well). Eventually, depending on how the UV modification succeeds, I will publish on my site another detailed review. In the mean time, I did a few tests of the unmodified unit in UV photography, which merit some discussion, best done in a post here. An Initial tests with Baader U filter seemed to show that this flash, with its bare-bulb head and a 12 cm aluminium parabolic reflector, is fully capable of generating UV images. However, the xenon tube clearly shows in VIS the tell-tale yellowish/brownish tinge of UV-cut coatings. I took all pictures with a "full-spectrum" Micro 4/3 camera and CoastalOpt 60 mm Apo lens. First I took a picture of the AD200 xenon tube used in the bare-bulb head, with Bowens R500 studio flash equipped with non-coated tube and Baader U filter. The Godox tube looks slightly dark, but not dramatically so. Imaged in the same conditions, a UV-cut filter like the Baader UVIR-cut looks almost completely black. Just for the fun of it, in the above picture I used as UV source the unmodified Godox AD200 with bare-bulb head and 12 cm parabolic reflector, and Baader U filter. Higher contrast, but otherwise the image is not too different. You can clearly see the spiral trigger wire both in front and at the back of the tube, which is transparent enough for this. Then I switched the Baader U filter with an Asahi Spectra XRR0340 filter, which is an interference coated U-340. Even higher contrast. Note that the protective glass envelope around the tube is completely transparent in all images. Only the tube is coated, and the increase in contrast suggests that it is blocking more of the shortest wavelengths that pass through this filter. However, even with this filter, the tube is nowhere as UV-opaque as a typical UV-cut filter. Does this mean that the Godox AD200 can be used in UV photography without conversion? Not so fast, a really reliable test is done with a spectrometer, rather than by visually comparing images. To compare very different flash units in a meaningful way, I previously normalized the graphs to display the peak emission level as a value of 1. This is simple, but not really meaningful. In the above graph, instead, I normalized each spectrum to display the same area under the curve between 400 and 700 nm (i.e., the VIS range). In this way, now that the VIS emission is normalized to be the same, we can better visually compare the relative proportion of UV to VIS in each flash. I will give the details of the calculation elsewhere. The four spectra are: blue thin line: Metz 52 AF-1, a typical speedlight that completely filters out UV. Useless for UV photography. green line: Bowens R500 with uncoated tube, at full power. Plenty of UVA. red line: Bowens R500 with uncoated tube, at lowest power. Thanks to the new way of normalizing the graphs, we can immediately see that now the proportion of UV to VIS is much higher than at full power. I will explain elsewhere why, but this is expected. thick violet line: Godox AD200 with unmodified bare bulb, at full power. Not much UV. We can see that the tube coatings are doing their job, and that the unmodified tube is a rather poor choice for UV photography. In part, the misleading results obtained by visually comparing the images are due to TTL flash metering. The flash was simply pumping out more of its abundant power to compensate for the low amount of UV, quite enough to force it through the transmission "tail" (380-390 nm) of the UV-pass filters.

SAFETY WARNING: UV-C is dangerous to your eyes and your skin. UVP DOES NOT SUPPORT USING UV-C ILLUMINATION. [UV SAFETY] UV-C Light Dangers I saw this video on YouTube. Maybe someone will find it interesting.

As we are all fans of UV related stuff I thought I'd share this. I have no affiliation with the seller. This antique quartz spectrograph came up on ebay recently - https://www.ebay.co.uk/itm/223444755096 The guy is open to offers on it and he does have his own (none ebay) store as well - https://jasonclarkeantiques.co.uk/collections/optical/products/quartz-spectrograph-by-adam-hilger-ltd-london

Hi all, Yesterday there was a thunderstorm at my hometown and grabbed the opportunity to catch some lightnings. A stack of 2 photo's in the same lightning sequence. I don't understand the green in the upper left corner. There was also bar on the left side but I cut it away. Nikon D70, Nikkor 50mm 1.8D, ISO 1600, 30 sec f/1.8, stack ZWB2 360nm, BG39

Any material that spreads light out and passes UV? Thinking of a light modifier to make flashlight beam less pinpoint. Thanks, Doug A

I've just had a very geeky few days evaluating a Phase One IQ4 Achromatic camera. Medium format BSI sensor (53.4 mm x 40.0 mm), 151Mp, black and white. Thanks to Teamwork Digital Ltd in the UK for making this possible and sending it to me along with an adapter to use my Hasselblad lenses and a really solid tripod. This was one that really interested me, as it should be good for UV as well as visible and IR, and I could try out my Zeiss UV Sonnar on it, as that was made for the Hasselblad 6x6 cameras. First impressions, it is very solidly built, and very well made. Here's a couple of pictures of the camera with some of the lenses I was trying out (El Nikkor 80mm f5.6, and the Zeiss UV Sonnar). Was able to take some images in UV, visible and IR and thought I'd share a few here. Landscape - Chobham Common in the UK in the IR and visible. Natural light in the evening. IR (Zeiss UV Sonnar, Hoya R72) Visible (Zeiss UV Sonnar, Schott S8612 1.5mm plus 420nm long pass) IR (Zeiss UV Sonnar, Hoya R72) Product shot in visible light using a big softbox. Single Bowens GM500 flash. Flower shots (from local flower shop - Tangerine and Green, Englefield Green, UK), in visible and UV. Single Bowens GM500 flash with quartz tube. Sunflower in UV (El Nikkor 80mm f5.6, Baader U) Not sure on this one - Dahlia perhaps - anyway, a white flower in UV and visible. Visible (Schott S8612 1.5mm plus 420nm long pass) UV (Baader U) These images have obviously all been reduced in resolution for sharing. As an example of the resolution of the original images, below is the image of the Sunflower in the UV along with a region marked in red. That little red square is 1000 pixels by 1000 pixels, and this is what it looks like in the original image. Working with the files is certainly challenging for the computer - a full size image in high quality jpeg is around 60Mb and the raw files are pushing 200Mb. You need a lot of storage with a camera like this. Not seen much UV imaging done with medium format, so thought it would be interesting to share. Unfortunately with only 3 days with it, I barely even learned how to use it, but it certainly impressed me in that short time. It has now sadly gone back to the dealer, and if I want to buy one I'll need to get buying those lottery tickets.....

I have a full spectrum camera, ioriginal Kyoei 35mm clone with his ZWB1 2mm and BG39 2.3mm filters. Looking at a chart for the ZWB1, it appears to have almost 0% transmission at 365nm. Is a different filter required for the lens? Perhaps I don't need the ZWB1 at all since a filter is fitted to the flashlight? Thanks, Doug A

Saw this on ebay and wondered how much UV it would actually kick out? Here's the lamp. It was a 'health lamp' made by Philips in the 1960's. Here's the irradiance spectra at 50cm from the bulb. Scary, scary lamp... Interesting though - it's a mercury lamp combined with a tungsten one in the same overall package. Surprisingly there seem to be quite a few for sale on ebay for not much money. I wonder how many people got badly burned by them when they were more commonly used?

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.

I have just assembled a 309nm LED light with 9 x 3w 309nm LEDs. I will make a second light the same & use then for UVB fluorescence. This is a visible light photo to show the setup & the consumption on a 12V DC battery. It is fan cooled, barely gets warm. What you see from the LEDs is the out of band light, it doesn't even register on the spectrometer, just a nice narrow spike at 309nm.

Safety note - this talks about high intensity UVB light sources. Please do not attempt this type of work yourself without taking the correct safety precautions. Over the last year I've been building a UV transmission microscope to help with one of my projects. One area that needing modifying was lighting, as I wanted to have a good light source in the UVB region at 313nm. As a basis for it I decided to use a mercury xenon light and a small Zeiss 50W came up for sale on ebay so I snagged that. Here's how it looks. In the exit port is a metal tube with a lens at one end to focus the light. This tube and lens can be moved back and forth by turning a black knob on the side of the light. Problem is the original lens is glass, so no good for UVB as it was blocking everything below abut 320nm. It was a non standard diameter so I couldn't find a fused silica replacement. In the end I had a new tube made, threaded on either end for Thorlabs SM1 tubes, and got a Thorlabs 20mm focal length aspheric fused silica lens as a replacement. Original and new tubes shown below. When I originally used this light for UVB imaging I used it without any lens, so obviously lost a lot of light. As a quick check I did some irradiance measurements without the tube and lens, and then with the new tube and lens in the focused position and in the defocused position. In the focused position the irradiance at the brightest area was about 600x that when no tube and lens was present, and at the defocused position, it was still about 30x more intense than without the lens. Interestingly in the focused position it actually produced a slightly fuzzy image of the two electrodes in the mercury xenon bulb and the arc between them when shone at a surface. The image below was taken using a 313nm Edmund Optics OD4 bandpass filter in combination with a Hoya U-340 4mm filter, using a monochrome modified Nikon d800 and Rayfact 105mm UV lens. The light was shone at a piece of white paper inside a box painted with Semple Black 3.0 paint and it was the image projected on this paper that was imaged. In the image above, the lamp is orientated vertically and the electrodes at the top and bottom of the image. This was about as sharp as I could get it, as I'm limited with how close I can get the lens in the tube to the bulb without touching it. More funky was that using that camera and lens I was able to capture UV videos at 313nm and 365nm using EO bandpass filters in combination with Hoya U-340 4mm. They show the arc flickering and moving about slightly on the electodes. I've uploaded these to youtube, and the links are as follows; 313nm video - 365nm video - The increase in brightness will be useful for my work, but it could actually be too bright now and damage the samples. I will be trying it in the defocused position, as even that should be significantly better than with no lens. I also may get some fused silica diffusers from Thorlabs and mount those at the other end of the tube with the lens on it, to help make a more even light source for microscopy. As mentioned at the top, work like this can be extremely hazardous, producing very very intense UV light down to and below 300nm. Do not attempt this yourself without an understanding of the hazards involved and how to protect yourself from them.

I was browsing the forum and I ran into a link for this. http://www.exo-terra...tile_uvb200.php It seems pretty interesting and for the price I almost ordered the 25w version right away, yet I'm wondering if this will actually be any different from what I have right now. I use a QB39+ZWB1 filter stack and I'm getting a ZWB2 soon to see if there's any positive difference. I have lenses that can pass some UVB (Soligor 35mm f/3.5 and Industar 50-2).

As you all might know, quality UV sources with a continuous spectrum can be hard to come by (if we exclude the sun), especially if your finances are limited. That's where I got lucky. Ulf W was very generous to me, and he donated to me one of this Speedlite 199As, that he no longer uses, so that I could convert it. I'm very thankful for that. I own a Nissin Di866 Mark II as well, but my father would never let me convert it. It might be way too complicated with that one anyway. On the other hand, my father helped me very much with the conversion. We took the flash to his workplace, where he had a screwdriver small enough to open the head so that we could see what next. We took out the Fresnel window, and cut everything but the edges with a rotating file. Here's the cut out piece, the plastic created weird hard clumps. We then further smoothed the edges. Here's the finished hollowed out window. And here's the result. A full spectrum flash with the discharge tube fully exposed. Here's two pictures I took with the help of this new gadget. converted Canon 1100D, Industar 50-2, QB39+ZWB1. For the dried flowers in a cup I used a fluorescent 40W blacklight as a supporting lightsource to help me focus and decrease the amount of flashings I had to do.

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