On 4/2/2010 5:40 AM, Orchid XP v8 wrote:
> Mike Raiford wrote:
>
>> Interestingly, UV imaging can also be used in forensics to find
>> evidence of an injury after the bruise has faded in visible, it will
>> show up in UV wavelengths for quite some time.
>
> If you believe NCIS and so forth, UV makes blood and other bodily fluids
> glow bright green. (I never did figure out why...)
>

Only if treated with Luminol, the I think it's more of a dull blue....

>> Eventually I plan on buying an inexpensive P&S modified to capture UV,
>> visible and IR. Its UV capability is one of the reasons. I've always
>> wanted to capture what my eyes cannot.. .
>
> I've been watching Richard Hammond's Invisible Worlds. Some very cool
> stuff, but unfortunately the cool stuff is only on screen for, like, 2
> seconds, and then we get Hammond chattering some more.

I hope that show is available in the States soon, I've been following 
the guy who did the UV Photography's blog for quite some time.

> I'd love to do the whole trip with time-lapse photography, high-speed
> photography, UV and thermographs, etc. In fact, I've often wondered what
> the world would look like if you would see radio waves. (I'm guessing
> that due to the absurdly long wavelength, most objects would be too
> blurry to see.) I've even wondered what the world would look like if you
> could see sound.

Interesting thought. Not sure how to build a detector for radio waves, 
though (in terms of forming an image on a plane ...) it's exceedingly 
difficult to detect thermal IR, I can only imagine the difficulty in 
focusing radio waves onto a plane.

> (Eyes and ears both detect waves. Eyes detect only three frequency
> bands, but with ludicrous spatial resolution. Ears detect waves with
> rubbish spatial resolution, but insane frequency resolution.)
>

It's amazing when you look at how your auditory system works. Your brain 
essentially gets the Fourier transform of what you're listening to. Also 
interesting how color vision interpolates between 3 broad bands of 
wavelengths to give the perception of a huge amount of hues. Though, 
because there's only really 3 different frequencies detected, you get 
some metameric failure for certain colors. Different frequency spectrum, 
but they look identical. A good example of this is when you photograph 
something whose color is in the violet end of the spectrum. Our red 
receptors are a little sensitive to the very short wavelengths of 
visible light, giving us the perception of purple. The red elements on 
most digital cameras' Bayer arrays don't usually have the same ability 
to pass the short wavelengths, giving certain dyes and flowers a more 
blue color than what your eyes perceive.

It's fascinating how we process information from our world. I've often 
wondered why we perceive blue as-- well-- BLUE, rather than red. I'd 
love to know what the world would look like if I had tetrachromatic or 
even pentachromatic vision. Some of the subtleties of some colors would 
definitely be more obvious. Fun stuff.

-- 
~Mike

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