Easter is approaching...!

Easter is approaching and quite some shops exhibit the traditional easter decoration. I was curious to see, how that white ostrich egg would look multispectral.

[as usual, a click on an image opens up a larger view]



Now that made me curious and the idea was to investigate the behaviour in terms of fluorescence these eggs (their eggshell more precisely) might show.

A Baader 2" UV/IR Cut Filter was used for the visible and fluorescence light shots, a Baader 2" U-filter for the UV shots together with that calibrated X35 lens I made, the UV Nikkor 105mm and an unmodified Nikon D70.

Now the big surprise is, that brown eggs exhibit some very unusual behaviour - they glow mysteriously red if you point a UVA light source to them; in that case here I used my mobile UV LED flash/lamp.



So why is that you might ask. It is UV stimulated visible red fluorescence of the porphyrine contained in the brown eggshells! This can be proven using a spectrophotometer (USB2000 in my case) which measures the reflected and emitted light from that eggshell with a fiber optic probe. The excitation source is quite strong, this is why that 365nm line is way off that graph. You see some response around 480nm (blueish) plus these two red porphyrine peaks at 675nm and a bit weaker 635nm.




Remember the first white ostrich egg shot I showed you above? I wondered if that one would also exhibit that effect, but the visual experience and the spectrophotometer reveals only a strong blueish response around 480nm plus a quite weak peak at around 635nm.



That made me even more curious and I got a fresh set of eggs from another vendor and indeed there it was again, that red fluorescence. Quite weaker but it was there, aside of some strong blueish fluorescence (as with that white ostrich egg):



The spectrometer confirmed these visual findings, the porphyrine response is clearly visible:




So I hope you enjoyed today this more scientific journey with me!


Stay tuned, more will follow on these fascinating subjects...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

X35: Breaking Ice - multispectral

Spring is here finally, but still we have cold nights. When I made use of the fine weather today and that great sun, I found quite some ice in the pond in the Freudenberg park opposite my house ("Hermannshof").

A Baader 2" UV/IR Cut Filter was used for the visible light shots, a Baader 2" U-filter for the UV shots and a B+W 092 IR filter for the IR shots together with a freshly calibrated X35 lens and a unmodified Nikon D70.

The impulsive idea now was, to find out, how differently visible light, ultraviolet and infrared would show the same scene.

[as usual, a click on an image opens up a larger view]

Here now first the visual light shot:




then the shot using the UV filter to get purely reflected UV:




and finally the shot using an IR filter which only allows infrared light to pass:




So what have we here now? Using the above three images, the following image was generated through a mapping of the ultraviolet shot to the blue channel (UV->B), the visual shot to the green channel (VIS->G) and the infrared shot to the red channel (IR->R) of the resulting image. This method is called "multispectral imaging" and is used in 
quite a few scientific fields.




Isn't it interesting, how IR contrary to the visual and especially ultraviolet shot penetrates
the ice surface and makes that leaf so clearly visible? UV however bounces back right from the ice surface, so "illuminates" 
the ice nicely.

So I hope you did enjoy this new method!

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

X135: Spring is here!

Spring is here finally! So I grabbed my unmodified Nikon D70, a tripod, that calibrated X135 UV enabled lens, the great Baader 2" U-Filter mounted on a Nikon AF-1 gel filter holder and a Nikon PN11 extention ring to do some flower shooting in that wonderfully maintained Freudenberg park here across the street in Weinheim/Germany where I live. So enjoy some sets in visual and UV light (visual light / UV)!
[click on image to see a larger version]




















I find it fascinating, how nature has hidden so many beautiful secrets from our human eyes but allows others like bees and insects to see that. Now, modern technology allows us to reveal these secrets. Take the 2nd set for instance: That crocus reveals some interesting UV pattern shown as light patches which are highly UV reflective spots. Insects and bees can see UV, so they will be attracted by that to find the sweet nectar and the pollen. But look closer at the visual light shot. Do you see that very faint blueish spot where the reflective spots on that UV shot are? It is there, we just overlook that so easily....

So I hope you enjoyed a few glimpses of spring 2008 with me!

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