Infrared and Water... A Semi-Tart response to Rolland

["Editor - P.O.V. Image Service" <editor@xxxxxxxxxxxxxxx>]

Rolland ("the headless Thompson Gunner" -  Warren Zevon told me so)
wrote:

>
> "Your test with a camcorder and a glass of water is
> nowhere near sensitive enough to demonstrate that water does not absorb
> infrared as another poster has said."
>

> 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.

And again, the veins AND the water in them are very small in volume!

> 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,

NO!

Look, the vein experiment demonstrated differential scattering!

The size of the container that the vein was tested in was a controlled
(not
variable) experimental factor here...

> 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.

Speaking of which did you READ the GUYOT quote, about how differences in
the
Amount of Water in different plant structures could cause significant
differences
in the way the plant is imaged in NEAR-IR?

It's the water AND it's interaction with the plant structure!

>  I still stand by my statement that in general water
> does not absorb IR to any significant extent compared to visual light.
> Glasses of water record clear on IR film, small pools of water are
> transparent, etc.

Yes and you can see through small "window panes" of ice... BUT YOU CAN'T
see
through even 5 feet of the same ice!

Your logic is flawed..  Just because absorption is not easily measurable
with
small volumes of water, that does not mean it is not a fact!  Your glass
of water
did not appear blue either, did it, nor do individual ice-cubes?...  But
get a a
large volume and they both exhibit a shift to the blue end of the
spectrum..

> This is based on my experiences not some physic's text
> book.

Ahh... The kind of logic that says people can be scaled up to 40 feet
tall and
still walk..  Or, wow, how cool it would be to have a cheetah the size
of an
elephant..  The fact is that macro-scale physics is different..   I'm
really
getting tired of this...  Your ancestors must have been the ones at the
dock
telling Columbus that the world could not be round.. Why? "See, to all
appearances it is flat!"


We've given you everything, scientific study cites, instruction on why
this
happens at the simplest level...  OK, here's an experiment I AM willing
to try!
We both go to a steel mill and stand in front of the door to a blast
furnace...
You are 6 feet from the door in a wet suit and I am also six feet from
the door
and in a wet suit and scuba gear.  The only variable difference will be
that I am
in a perfectly clear cylinder of water with five feet of water and one
foot of
air between the furnace door and I.

Then!  The really fun part. The steelworkers open the blast furnace
door,
allowing huge amounts of heat (mostly as IR radiation) to pour out at us
both...
Guess who gets the permanent second skin of rubber (or Dupont neoprene)
and
watches his flippers curl up? I am willing to bet the questions ent then
and
there..

> 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.

What the heck are you talking about? I make my living taking photos...
INCLUDING
INFRA-RED IMAGES. Whose the one sitting theorizing and spinning
hypotheses for
the characteristics of matter by using a single glass of water as a
referent?

> If you don't like my test maybe you should do
> your own test and post the results to the list. If you are going to talk the
> talk, walk the walk, go out and take some IR underwater photographs
> otherwise your glorious theory is just a big waste.
>

Look, I accept the results of studies by Guyot, etc.. In fact, if you
want, I
will approach my contacts at Kodak, RIT, and elsewhere and get you an
actual
spectral analysis of the spectral response curve for H20...

Until then, please go back to looking at your hand's reflection in
various
objects...


Keith Krebs



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