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White Zinnia in visible light:

White Zinnia in UV induced visible fluorescence, variant 1:

White Zinnia in UV induced visible fluorescence, variant 2:

I hope that serves as an example what could be done with those UV flashlights, but of course those are useful for many different applications such as stimulating visible fluorescence, reflected UV photography, forensic, dermatological and dental examinations and photographic recording, curing of UV glue / bonding, as well as leakage detection etc.
Stay tuned, more will follow on that fascinating subject as part II...
More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos