I have reported about my findings about Gaillardia and that prominent UV pattern it exhibits, hidden behind a beautiful yellow/red pattern. Now lets have a look at some spectrometric reflection measurements.
[click on image yields a larger one]
Remember, this is the visual appearance:
The trichromatic image ("butterfly vision" shot) (UV+B+G) using XBV2 filter:
shows this underlying strong UV reflection pattern of the petal body. The spectrometric analysis confirms, that the UV reflection gets quite strong towards the tip (ca 320-420nm). The tip itself shows also some green reflection (this is why the tip appears yellow = red+green).
Reflection measurement (100% = white Spectralon):
Now, my XBV2 filter allows UV to pass and to be recorded in the camera as Blue. This is why the body of the petal appears mainly blue. The tip appears whiteish green since it is Blue (=UV) mixed with Green. Remember: the red channel is suppressed in the trichromatic image, so the strong present orange + red reflectance from about 600nm onwards does not matter in that case!
The tetrachromatic vision image including the red channel would look like the following image, since it would also include the strong orange and red reflection. This results in white tips (UV=Blue + Green + Red) and a magenta petal body (UV=Blue + Red).
Tetrachromatic image ("bee vision" shot) (UV+B+G+R) using XBV2 filter:
Stay tuned, more will follow on that fascinating subject...
More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos