what wb for near uv light ?

[armando_m]

Paco de nada

I'll process more later

Thanks Ann , I thought I had removed must of the blues, I used cnx2 and Ps cc/acr, but obviously didn't remove it completely, seems you also increased the exposure a bit?
Thanks for taking the time to post your edit

[Ann]

I don't remember exactly what edits I made (and I have already trashed the file so can't check!).

I just downloaded the file from the NG page but I do remember that it didn't have an embedded Profile so I assigned it an sRGB profile and would have probably have done a quick Auto Tone after that so that the image looked normal on my screen.

Then I went into ACR's HSL Panel and pulled the Purple Saturation slider back considerably.

You could almost certainly do a much more refined job than I did by doing the Purple-desaturation in a Layer-Masked Layer.

[Ann]

Sorry, that got posted in the wrong thread!

[arthurking83]

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?
....

Is there anything in any of the images approaching near white or grey or black?
If so, use one of those areas as a reference point for a grey point in the WB tool.
Do you use ViewNX2 as well or just CNX2?
Same thing with the WB tool.
I find using the grey point for WB choice usually makes a nicer overall WB rendering.

Once you get close to how you want them to render in terms of WB, then in CNX2(VNX2 doesn't have this... ) use the Selection Control Point tool(not colour control point) on any areas that still look too blue/purple for 'ya.
Obviously you enlarge/decrease the area for selection, and in the selection properties type in the tool you choose Colour-> Saturation/Warmth and desaturate as required and warm it as required.

If you have a sample NEF file I could test with, I can try to help.

Many years back I was asked to attend a body art show and they had a UV fluorescence session where the folks were all lit under very strong UV light .. but little other visible light.
I just used a grey point for my WB, on a white towel in some of the images, and the very strong purple WB rendering all but vanished. Very easy to do and then applied to all images.
I just went back to some of those images to check what the whitebalance values ended up as .. and you could try these as some start points to play with.

So in CNX2 on an NEF file: Go to WB tool in the Develop tab. Change the Set Color Temperature to Set Grey Point. Once you do this, you are then presented with a dropper tool option AND the option to type in values into the red/blue channel.
In the red/blue channel try these two values as a start point.
Red = 2.2 : Blue = 0.2
Note they can be adjusted from 0.1 - 10 lower meaning less, higher meaning more.

Those two values gave me a white towel rendered white under mainly UV light(at about 390nm).
As you have some non UV ambient to deal with too, I'd say you've going to need to lower red and increase blue by comparison.

[armando_m]

Arthur, thanks I had forgotten about the WB marquee sample, it works like a charm , I used the sand to create the gray sample, which it likely is not 100% gray, and a proper gray card would work better

here is a before and after