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UltravioletPhotography

Fire Dive Gear - underwater fluorescence photography equipment


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I came across a link to this site today - Fire Dive Gear, http://www.divephoto...ce-photography/

 

The reason I'm sharing is because they are selling a fluorescence test slate, designed to help with white balance. Link to that here, https://firedivegear...nce-test-slate/

 

Given the costs of some of the fluorescence standards, this might be worth trying. I have no connection with the company, and sharing in case it's of interest.

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enricosavazzi

Talking about cheap fluorescent test targets, some time ago I somehow found the following UK web site (I cannot remember if it was mentioned on UVP or I just found it googling around):

https://glowtec.co.uk/catalogue/

 

I did keep a bookmark to their white-fluorescent paint, but never got around to ordering a jar:

https://glowtec.co.u...uv-paint-white/

 

PS - Shipment to Sweden (and probably the rest of the EU) costs a lot more than a small jar, so I am passing up on this.

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If this target contains more than one ingredient (like, just saying, a red, a green and a blue component), would the color vary at different exitation wavelengths, since the spectrum given off by a single components can vary a bit? Think about the different colors the same mineral can have under UVA, UVB and UVC lights.
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Enrico, thanks for the that link. They make some other products which might be useful for my work. If I end up ordering anything from them, I'll order some of the white fluorescent paint as well and give it a go.
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enricosavazzi

If this target contains more than one ingredient (like, just saying, a red, a green and a blue component), would the color vary at different exitation wavelengths, since the spectrum given off by a single components can vary a bit? Think about the different colors the same mineral can have under UVA, UVB and UVC lights.

Potentially, yes. Other than trying, there is no way to know, since we do not know the chemical composition of the target. For example, several organic fluorophores used in microscopy are quite selective in their UV excitation and emission peak wavelengths. In some cases changing the concentration of a dye changes its color (e.g. if I remember correctly, concentrated fluorescein solution is reddish-brown in VIS, diluted is yellow-green).

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It would interesting to compare these two fluorescence targets, this first one Andrea has,

and the one Jonathan has linked to above

 

I note that the Fire Dive Gear site believes explains that blue light induces better fluorescence in marine organisms. So I'm wondering if their fluorescence target is tuned to blue light rather than UV light?

https://firedivegear...ht-vs-uv-light/

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Unfortunately, the item they advertise on their page is not exactly like the item I received.

Most importantly, the one they show on their page has WHITE.

The one I got has no WHITE, and has two ever so slightly different oranges, and the color slates are not in the same order either, but the order if not the problem for me.

I really wanted the white. I have already written them asking for a slate that looks the same as the one they advertise.

Other than that gripe, I like the card very much, it comes with a short lanyard with a built in compass in case I get lost while diving.

So... unfortunately, I think will be sending this item back.

Here are pics.

 

The difference, what they advertise (left), what I got (right):

post-87-0-57317000-1583569312.jpg

 

Front:

post-87-0-77665900-1583569332.jpg

 

Back:

post-87-0-72108400-1583569352.jpg

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I can't believe they put 2 orange tiles and no white tile on there. That's so shoddy, and surely is a mistake.
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I don't know what the two oranges are about.

I understand that water filters out UV, so violet may work better at lower depths, but i want the white.

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This it is a bit ride to show one & send a different one.

UV travels well in water, at short distances, IR is blocked.

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Inland lakes and rivers with very humic-stained water can have the highest transmittance in near IR.
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I want to mention that the Dive Card is high quality and very well made, my gripe is that the photo they have shows white.

They have told me that the two different orange plates are for different wavelengths of UV and blue up to 455nm.

Several research universities requested they be made that way.

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It would interesting to compare these two fluorescence targets, this first one Andrea has,

and the one Jonathan has linked to above

 

I note that the Fire Dive Gear site believes explains that blue light induces better fluorescence in marine organisms. So I'm wondering if their fluorescence target is tuned to blue light rather than UV light?

https://firedivegear...ht-vs-uv-light/

 

Andrea zeroed in on the real issue. Not having the White is not as much of an issue as the nm of the light used to excite.

Indeed, the Dive Card is designed to fluoresce using 455nm light, and you can read all about that in the link below.

So that card is not pertinent to use with 365nm UV.

 

The Dive Card doesn't fluoresce correctly using 365nm light, the magenta shows up as another orange, the yellow becomes a lime green (or a white, WB depending).

Also, the back of the card is white under regular visual light, using 365nm light that white is black, or very dark brown (as with the Spectralon White and the PTFE powder,

but using actinic 455nm peak light the back of the card is white.

However, I tested it today under actinic lights used on my aquarium. Actinic lights peak at about 455nm.

Under the actinic lights the card colors looks exactly like it does in usual full visual band light, except it fluoresces.

Read the link and post any thoughts.

This link was written by Lynn who sells the dive card:

https://firedivegear...UV-rev1.doc.pdf

 

This all makes me curious about various possible fluorescence lighting peaks. Some kind of chart showing different excitation nm and how and why.

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Andy Perrin
/Cadmium quote snipped/

Thoughts:

1) Lynn's comments suggest that the blue rule applies specifically to underwater things because UV doesn't go down as far in water as blue, so the sea creatures evolved to fluoresce mainly under blue.

2) Obviously flowers (mostly) are not underwater, so that logic wouldn't apply to them. (It's still possible blue works best, but it would have to be for a different reason.)

3) We need some actual info on which wavelengths flowers fluoresce best under.

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Andy Perrin
Hah, I didn't look at what time you posted it. I think my thoughts are still relevant though, so that part can stay.
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Also, white fluorescence under blue light is strange (shouldn't be possible I think). Conventional fluorescence converts the exitation light to light with a longer wavelength (Stokes shift), so you should be getting yellow fluorescence+reflected blue (like white LEDs). Thinking about LEDs, what about the new ones that use a violet or even ultraviolet "pump"? Unlike CFLs, the only light exiting the phosphor is violet-UV, and they produce white light. Could be interesting to try that out.
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3) We need some actual info on which wavelengths flowers fluoresce best under.

 

What fluorescence do you want?

For induced IR fluorescence, a 450nm peak light is great. I like using 405nm LED or BG39 filtered white LED.

Mark had some great photos with a cyan, approximately 488nm light source.

The Visible induced fluorescence looks best under 365nm. But saying that I haven't played with a 385nm LED and that might be better/different/worst. Don't know. I may add that light to my 365nm and 405nm leds.

Amazon does have cheap 385nm E27/E26 bulbs.

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David, The Cyan light that Mark uses is for IR fluorescence, which is the standard excitation for IR fluorescence. The 356nm also works obviously, but the old standard is green/cyan to induce IR fluorescence.

I don't know if Mark has used the cyan for any visual range florescence or not.

 

What Lynn is saying is that visual fluorescence looks better using 455nm, for bio-florescence, but I am not clear if that is simply because of being underwear or more to do with the sea life itself.

 

https://firedivegear...UV-rev1.doc.pdf

Reading that link, he explains the best wavelength, and also talks about Charles Mazel who worked on determining which wavelength(s) of light cause the greatest spectral emission of sea creatures.

 

Here is a page and a video about Charles Mazel:

https://oceanexplore...el/welcome.html

 

His Nightsea page:

https://www.nightsea.com/

 

Interesting stuff here:

https://www.nightsea.com/resources/#

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