re: InfraRed and Water - A comprehensive approach - Final Chapter

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

Our final chapter opens as..

Rolland Elliott wrote:


> Given these facts it is very
> unlikely that any photographer shooting IR film will ever have to be
> concerned or compensate their exposure due to the IR absorbence of water
> unless they are doing underwater IR photography (with distant subjects)
> which is virtually non exsistant.

Wrong.. Wrong.. Wrong...

The more water vapor the less Near IR in a ratio to visible light!

And don't talk about red sunsets and sunrises here... That goes back to
refraction and scattering by particulate matter in the atmosphere... At
the
extreme incident angle of a sunrise or sunset, that scattering
overwhelms,
finally, the absorptive qualities of water vapor..  Talk to any long
term photog
and they can tell you that the most beautiful sunsets are in dry dusty
conditions
where there is increased suspended particulate matter in the
atmosphere....  The
residents of Puerto Rico, for example, enjoy their most beautiful
sunsets when
the trade winds blow African Sahara dust across the Atlantic..  And
desert
sunsets are most beautiful in windy conditions where more particulate
matter is
kicked up into the air..

>
>
> Whew, Rolland.

My words exactly...!

Whew Rolland... Got it now?

I apologize to all for the length of this post, but we don't need to
banter on
about this.. The simple fact is H2O is IR absorptive AND the surface of
a body of
water will remain IR reflective from many incident angles..  Any IR that
penetrates the surface will be quickly absorbed by the water.. If that
were not
so, the only option would be for IR to bounce around in a pond or
seawater until
it hit a rock or some other object...  If that were true, you would see
the
interior of a body of water in a Near IR image: fish, rocks, the
seafloor, all
would be visible... It just doesn't work that way in reality...  In
fact, if you
want to see through water, concentrate on the blue and UV rays of
light....

Given your comments on aquaria, etc... I can bet that as fish develop in
the near
absence of IR, that imagery of aquatic fish, plants, and other animals
shot to
show UV and Blue differentiation would prove way more interesting than
UV imagery
of said-same items..  Adaptive evolution would lead aquatic dwelling
living
things to adapt coloration that could be seen by other denizens of the
watery
realm...  Although with IR and a limited amount of water you might get
some
nicely translucent appearing aquatic denizens in certain instances...

Keith Krebs

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