Rudbeckia fulgida: tetrachromatic butterfly / bird vision

Today a Rudbeckia fulgida flower portrait (with an invited guest) in simulated tetrachromatic vision (i.e. UV=blue, BLue, Green, Red) like birds or butterflies have.

[click on image to see a larger one]



For comparison, this is the normal, human vision version (i.e. Blue, Green, Red):



I found it especially interesting how strongly the flower center reflects UV (blue center dot) and how prominent that te "helicopter landing platform" is formed as white tips of the yellow flower petals.

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

Blue Bananas?

Well, something interesting and kind of funny today. I read on the net, that scientists in Innsbruck, Austrai and Columbia University, New York have found, that bananas emit blue fluorescence light when radiated with UV light of 365nm, but depending on the degree of ripeness of the banana. This is caused by breaking down of the green chlorophyll and these byproducts accumulate in the peel. So why not try to make that visible, since I have that equipment anyway here for my UV photography...

[click on image to see a larger one]

The bananas as we all know them in visible light:


Now radiated with my 365nm Nichia UV LED and with UV blocking filter in front of the camera lens:


Just looking at the blue channel makes it even more prominently visible:


So obviously bananas do fluorescence and it gets very obvious that the one in front is the ripe one, wheras the one in the back is the green, unripe banana. So have your UV light ready when shopping for bananas next time...!!

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

If you were a flower....

...and you want to make sure bees would find you, would you look like this?
[click on image to see a larger one]



Well another one of my "bee vision" series, so what you see here is UV+Blue+Green, in this case a Rudbeckia fulgida nearly buried between masses of high growing green prairie grass. The flowers petals are all yellow, no visible pattern and the center is pitch black (that why it carries the common name "Blackeyed Susan") - well, but only to the human eye...

Maybe I should say a bit more about this: Grass and foliage also reflect a lot of UV. So "just" having a high UV reflection does not help a flower much to be found by its pollinators - it needs a bit more "creativity". So how does it make sure to stand out of the crowd? Some flowers found a tricky way, they create a "landing platform" for bees and bumble bees, consisting of concentric rings (or other "nectar guides"), like that white and another green one. And inside there is that bright UV reflective center. But only with the help of these contrasting petals around it stands it out. But why is that invisble to us humans? Very simple actually, since nature is so efficient: we don't pollinate flowers, so why should evolution develop something visible to us if the flower has no benefit from us??

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

Gaillardia "Summerwind"

Well, I found a previously unknown (to me), pure yellow species of Gaillardia. Since that type of flower showed so many surprising aspects, I wanted to see what this new one hides from the human eye....

[click on image yields a larger one]

This now is the visual appearance as we humans are used to see:



The tetrachromatic image ("butterfly" shot) (UV+B+G+R) using XBV2 filter:



The trichromatic image ("bee vision" shot) (UV+B+G) using XBV2 filter:



This is the UV induced fluorescence shot using XCUT2 filter:



and this the reflected UV shot using XUVIR filter:



Well, also that flower shows some surprising properties ...

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