My UV torch for this experiment is fitted with a high-power Nichia 365nm UV-Led. I typically use this torch for illuminating a subject in order to focus Live View through a UV-Pass filter. For this task a UV torch is indispensible. Mine is a well-made beauty - the UV-Haiku by Don MacLeish.
Equipment used: Nikon D600-broadband + 105/4.5 UV-Nikkor
Here is my test subject: Lewisia longipetala 'Little Plum'.
(Or so it was marked. It does not look particularly plum coloured to me.)
Visible: with Baader UVIR-Block filter in sunlight

Ultraviolet: with Baader-U UV-Pass filter in sunlight.
First the original (cropped) version, then the white-balanced version.
You can see that the flower has a lot of UV-iridescence because of surface conical cells.


Ultraviolet: with Baader-U UV-Pass filter in sunlight and torchlight.
I was holding the torch at quite some distance from the flower
in order to fully cover the flower with the beam.
However, the shot appears blotch-ily bi-coloured both before and after white balancing.
FIrst the original (cropped) version, then the white-balanced version.


This last photo shows how I tried to desaturate the yellow false colour in the preceding white-balanced version.
This almost gives a monochrome look, but not quite. Just a reminder -> a monochrome look is expected
when shooting with such a narrowband UV-Led light when little or no sunlight is mixed in.

Here is one more comparison. In this case, the UV torch & sunlight combo turned out better.
Although not particularly monochrome, so go figure.
First the sunlight-only shot, then the mixed light shot. (Both were white-balanced.)


If I desaturate the yellow false colour in the preceding mixed light shot,
then I also lose the greenish false colour in the leaves.
This is mostly an artistic complaint, as I think we need to be careful with how we interpret false colour.
Because there are flowers which do have a yellow false colour after white balancing,
I think it would be difficult to know when to remove it and when not to if using this kind of mixed sunlight/torchlight.
