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UltravioletPhotography

UV Dental photography


Mohamed Elmaghrabi

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Mohamed Elmaghrabi

When we meet later in May, in Scotland, I'll make a dental portrait of your new tooth .... in UV of course ...

 

Meanwhile, get well.

 

 

OK Bjørn

 

I was asking Andrea about this topic Dental UV photography and she advised to ask you and while she is recovering, I will start asking >>what the gear you will suggest for that? :) I am trying to develop one and I have no idea where should I start.

 

My goal is to have ultra-violet induced visible fluorescence photography with a spectral peak of 365nm

 

I own Nikon D7200+ AF Micro-Nikkor 105mm f/2.8 + R1C1 flash

What I am thinking to do is buying 2 Nissin i40 Compact Flash and modified them to produce UV and put on them U-360 (UV)2.5mm thickness to block out Visible light and Hoya 52mm UV and IR Cut Filter on lens to get only visible light through the lens

 

I don't know how it will work or the result will be but what do think?

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Teeth fluoresce quite brightly under UV illumination.

 

UV Teeth fluorescence J1103174448.jpg

 

You need a UV/IR blocking filter over the lens and a UV light source. Could be a blacklight or UV-capable flash, or even a LED source.

 

The above portrait was taken with a Nikon D3S, and an SB-140 UV flash with SW-5UV filter attached. Baader UV/IR blocking filter over the lens.

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Last evening, I verified what Bjørn has shown. I shined my 365nm UV-LED torch onto my teeth (in a dark room) and saw a nice white fluorescence with perhaps a slight blue tint. And I note that my porcelain crowns also fluoresce. However my zirconium crown does not fluoresce and appears somewhat dark. :D

 

Your Nikon D7200+ AF Micro-Nikkor 105mm f/2.8 is an excellent combination for recording ultraviolet-induced visible fluorescence (UVIVF) of teeth.

 

I am assuming that your D7200 has not been modified in any way? That is, the camera has not had any internal filters removed? Such internal filters typically block ultraviolet (UV) and infrared (IR) light from reaching the sensor. With such a camera and lens, you can successfully photograph UVIVF without an additional barrier filter on the lens because the amount of UV/IR leakage would be small. However, to ensure total blocking of UV and IR, we would recommend adding a UV/IR-blocking barrier filter to the lens. For example the Baader UV/IR-Cut filter. You have mentioned elsewhere that you have a Hoya UV/IR-Cut filter. This Hoya filter should suffice for additional blocking on the lens if your D7200 retains its internal blocking filter. For a camera which has been modified by removing the internal blocking filter, the Hoya UV/IR-Cut filter might not be sufficiently strong.

 

Next, do you need an excitation filter on the UV-torch (or on a UV-flash)? The excitation filter is to ensure that fluorescence is only induced by UV and not by an visible or infrared leakage from your UV illumination source. With a 365nm Nichia UV-LED there would be a very small amount of violet or violet-blue "leakage" from the LED. You have mentioned using a U-360 to block visible light, and I agree that this will work well if the filter is sufficiently thick, say about 2mm. A thinner U-360 might pass some violet light. If you are using a UV-flash, then it is possible that there could be both visible and infrared produced in addition to the UV. If so then you would want to add an IR blocking filter such as a 2mm BG40 to the U-360.

 

For UV-induced visible fluorescence we typically make use of a UV-torch (flashlight) because fluorescence photographs are made in the dark and thus longer exposures may be needed. For this a UV-flash is often not sufficient. However, teeth fluoresce easily, so a UV-flash might be useable for dental work. (You will have to experiment with your UV-flash to determine if it is useable for your needs.)

 

Currently, the best torch we know about is the MTE UV 301 with Nichia 365nm LED chips. You can read about it at these two links:

http://www.ultraviol...3b-uv365nm-led/

http://www.ultraviol...rches-compared/

For other comments about UV Lighting, please run this search link: http://www.ultraviol...arch_app=forums

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Andy Perrin

Terrifying, nfoto. :P

But interesting. I've also observed my teeth glowing with a UV LED flashlight. Nails also fluoresce somewhat. I have a friend who got rainbow-colored hair, and she found that the dyes shined nicely under the black light.

post-94-0-62692300-1458526273.jpgpost-94-0-39346200-1458526281.jpg

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Mohamed Elmaghrabi

Thank You every body that's very helpful.

 

These Photos are not mine they are a photos of Sacha Hein a dental technician. and its different from the one Bjørn show here because these are blue .... why is that?

post-108-0-28425000-1458552547.jpg

post-108-0-20692600-1458552548.jpg

post-108-0-95318600-1458552548.jpg

post-108-0-94389200-1458552550.jpg

post-108-0-22891500-1458552552.jpg

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Filtration, white-balance setting, scene contrast, and exposure all contribute to a different outcome. One has to arrive at a useful setup for the intended use of the ensuing photographs I guess.

 

For my photo I probably set w/b from a Colorchecker card. No time to retrieve my field notes at present.

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Getting the correct colour in a UVIVF photo is not always an easy task. Try setting your camera to Auto or Daylight white balance. Then check the JPEG to see if the colour looks reasonably close to the colour you see under the UV illumination. If the teeth still look too blue using either Auto or Daylight, then you can probably make an adjustment to the white balance in your D7200 setting. I will look that up and write the instructions in the next post as I do not have a D7200 at hand. :)

 

White balance for fluorescence work cannot be set from a Color Checker card because it has no fluorescent patch which glows white.

 

BTW, PROTECT YOUR EYES and the PATIENT'S EYES FROM THE UV ILLUMINATION. The patient should always close their eyes when you make the photo. You should wear UV-blocking goggles to protect your own eyes from reflected UV. It would be nice if the patient also had some goggles to wear.

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D7200 settings

 

First set a neutral picture control.

The suggested settings should provide a reasonably accurate view of fluorescent teeth (given the proper white balance setting).

 

Photo Shooting Menu > Picture Control > Neutral > {select settings}

Sharpening = 4

Clarity = 0

Contrast = 1

Brightness = 0

Saturation = 1

Hue = 0

 

Next determine which one of these white balance (WB) settings works best for your choice of UV illumination.

 

Photo Shooting Menu > White Balance > Auto > Normal > {tweak WB grid, if needed}

OR

Photo Shooting Menu > White Balance > Direct Sunlight > {tweak WB grid, if needed}

 

After determining whether Auto or Direct Sunlight is the "best" WB setting, then you can refine the choice by tweaking the white balance grid.

To remove a blue cast, you would advance the center grid marker to the right along the horizontal Blue-Amber axis. After each advance, make a trial photo to check whether there is less blue in the teeth.

 

There is a third WB setting which could be tried. That is to set the Kelvin temperature. However, I'm not sure what to recommend as a starting temperature for fluorescence work. Perhaps the middle settings around 5000K are a good place to start if you want to try this. Higher temps produce redder photos. Lower temps give bluer photos.

 

Photo Shooting Menu > White Balance > Choose color temp. > {choose temperature}

 

 

Please let us know how this works out!! :D I have other suggestions I can make but these would require working with a raw file from your D7200. We can talk about that later if need be.

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Mohamed Elmaghrabi

Ok. thank you all...

 

I am now excited to setup the gear suggested by Andrea and I will keep you updated with the results. but it will take a while until I get my hands on them

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The blue can be also removed using a white balance tool in a photo editor. But I think you want to first try to get as close as you can with camera settings and only make use of editing if absolutely necessary to save on work time. Here is an edited example from your photos above. However I do not know if this edited photo is accurate in its color.

 

post-108-0-22891500-1458552552pn.jpg

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"White balance for fluorescence work cannot be set from a Color Checker card because it has no fluorescent patch which glows white."

 

Trivially true. However, as long as there are neutral elements without fluorescence inside the frame, one can indeed set a w/b. This is essentially a more refined way of using the camera on Auto w/b to see if the fluorescence match the visual appearance.

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