what wb for near uv light ?

[armando_m]

I got an invitation to shoot some corals,
the light used to get the more vivid colors is near uv
I'm using my regular d800

I'm wondering that a fixed wb will be better

Anyone has any recommendations?
The corals are about 10cm across
so it will likely not require a macro

Thanks in advance

[Akira]

Apparently you will be going to shoot corals under the visible light with the additional ultraviolet-induced visible fluorescence (which should be the main purpose of the use of the near-UV lighting).

I haven't heard about the suitable WB for that.  The best way would be, as always, to shoot RAW and try different WB settings in the post process.

[armando_m]

Thanks Akira

yes I'll shoot Raw

Hopefully I get something interesting and worth sharing

[David H. Hartman]

I don't know anything but I'm wondering if it wouldn't be smart to check the tri-color (RGB) histogram to make sure that no channels get blown or clipped. I'd shoot with the Neutral PC and then add whatever punch you want in LCH using Master Lightness for contrast and Chroma for saturation. Starting from an NEF in neutral you can still knock a person's eyes out with eye candy or be quite subtle as you choose.

That's my 2 cents,

Dave

[Akira]

Thanks Akira

yes I'll shoot Raw

Hopefully I get something interesting and worth sharing

I'm looking forward to seeing the results!

I think that Dave's advise should make a lot of sense.  Also, you may be better to bear in mind that the overall lighting can be dimmer than expected in order to balance the fluorescing light and the reflected light.  The pure fluorescence is definitely dim.

If you have a chance to shoot pure fluorescence, and the "near-UV" light emits only small amount of visible portion, then you may want to use a light yellow filter to cut the influence from the near-UV light to cut the reflection from the light source.  The corals fluoresce mostly in light green:

https://www.flickr.com/search/?text=coral%20fluorescence

[golunvolo]

So am I, looking forward to your results.

[charlie]

I'm not sure if this is of any help, but when I'm using my Baader-U filter to shoot the UV spectrum my white balance is bottomed out, so to speak, at 2000k.

If the light will be bright enough and you're using a camera with live view I would suggest to turn on live view and set the WB to 2000k, then dial it up through 10000k and set it to where it looks best.   

[Akira]

Charlie, you are talking about capturing the UV-reflected light using UV-pass lenses and UV-modified camera, which is totally different from the UV-induced fluorescence which is visible, as you know.

Armando is going to deal only with the visible spectrum using normal camera and lenses.

[Øivind Tøien]

I have so far usually kept automatic WB when I work with UVIVF, however when I have checked them out with daylight WB in CNX2, they become very similar to what the camera chose for me. I only have a Nikon L39 on the lens.

[armando_m]

I used an orange filter to block the strong blue light

While I shot with a warm WB, in PP I used daylight 5200

This were shot in a store, the owners are friends to a friend who is a biologist (remember the blue mushrooms I shoot?), a shipment of new corals was  just received, it is like eye candy with all the incredible colors and shapes

Shooting conditions were complicated but seems I still was able to get a few usable images

I have not looked at all of them but here is one I liked, the blue shadows are likely tentacles blurred due to a longish exposure

[beryllium10]

Armando - Very striking photo - brilliant neon colours from the natural world!  Thanks for opening the discussion and posting this result.  One minor comment - it might be worth placing some black card or cloth over the back of the tank to remove the distracting background (upper right corner).

Cheers - John

[armando_m]

Thanks John yes , I did not see the background while shooting 

Here is one shot without the orange filter, a bit of work to remove the strong blues

[Ann]

Armando:

I don't know which software you use but there is a very easy way to neutralize the purple/blue cast by simply desaturating those colours:

[golunvolo]

Oh, thanks Armando!

[Akira]

Armando, the first image looks promising, although I would have to agree about the treatment of the background.

Ann's correction for the second image makes sense, but maybe the UVIVF in light green looks less prominent?

How about this?  I opened Armando's posted JPEG in the latest ACR, with Exposure +0.50, Contrast +50, Highlights -100 and Clarity +10.