For my studio shots, I have been using the Nightsearcher 365nm UV torches to light the subject while adjusting focus. There are times when I have left these on while shooting flowers. My thinking is that if I use shutter speeds of 1/160, there will be little time for the UV torch to impact on the final image.
Here is an illustration of this effect with a striped Gazania; although they were shot on 2 separate occasions with different flowers, they were from the same species. I’ve included visible shots to show they are indeed the same variety.
Notice the increased yellow in the images with the UV torch left on? And that despite using 1/160 sec shutter speed. I have noticed similar when shoot orchids, where the yellow contamination from the UV torch is very prominent against the blue of the orchid in UV.
Hence to protect the images I shoot from any UV torch light contamination, I now cover the UV torch while shooting indoors with flash; I find it easier than switching the UV torch on and off.
Equipment used: Olympus EM-5, Coastal Optics 60mm F4, Baader U filter, IDS1 & 2 filters, Quantum X2D flash, Nightsearcher UV torches