Re: Infrared & Water

["Karl and Anita Shah-Jenner" <shahjen@xxxxxxxxxx>]

Rolland writes <clipped>:
>Obviously, you all missed the point of the test. It was in direct response
>to the incorrect assumption that veins are dark due solely to their water
>content.

Firstly I'll repeat what I said in response to another post "Hi there,
sorry to all for throwing my proposed answer to the list then
disapearing!  I was experiencing computer problems but now
I'm back to take the flack! :-)"

>Since my glass of water is a few hundred times thicker than the
>water collum in a typical human vein it was more than adequate, I also
>backed up this test with a Medical Reference book on IR photography. Before
>you jump up and down you should do some testing of your own and read the
>posts more throughly.

I did my own tests Rolland, did you do yours under purely IR light, or under
normal light with an IR filter over the front?  Mine were done:
a) under IR with a video camera, then
b) photographing into a pool of water 1 inch deep with HSIR and an 87 filter
over the front (result: black water)
c) photographing blood ...(note to Steve..yes - I did... ;-)

comparing blood and water under IR conditions, water IS more transparent
than blood when 'out of the vein', but 'in vitro' it's concealed under
flesh, composed of the mucky stuff I mentioned before which serve to diffuse
as well as reflect the IR, maybe this changes things, maybe not.

> I still stand by my statement that in general water
>does not absorb IR to any significant extent compared to visual light.


This is in conflict with a fair bit of information available on IR.

>Glasses of water record clear on IR film, small pools of water are
>transparent, etc. This is based on my experiences not some physic's text
>book.  If you're 30 meters beneath the sea that's another story, but none
of
>you are, you'are sitting in a chair, on your butt, in front of a computer
>talking about theoretical IR photographic situations, that you've never had
>any hands on experience with.

No Rolland - I read a fair bit, but I take very little as fact.  I test and
attempt to varify anything I'm not sure about - and even when I AM sure or
have come to my own conclusions, I'm still very willing to hear other points
of veiw.  Everybody has something to say, and it can all add to the picture.
I'm in it to learn, and I can't do that if I've got my mouth open and I'm
listening to the echos of my own voice.  (BTW, I have been 30m underwater
and it's all blue down there! :-)

>Peace Rolland

... and to you

Karl
West Australia
(as I said in my intro... thanks for putting up with me!! ;-)


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