BOARD00284

• Board Meeting Date: 1/12/1971
• Description: Agenda or Table of Contents, Minutes, Memos
• Board Meetings - Doc Type: Meeting

spectrum and then a wide range of infrared.
Away over to the right is a thermal infrared
region which you have seen in aerial studies
done related to heat phenomena. We are not
in that region. What I am talking about is
that narrow band between visible light and
that white line which is the extent of the
photographic film response.

There is a characteristic of almost all
of living plant tissue, especially that that
contains chlorophyl A where there is a strong
reflectance and a color infrared region. The
military developed a film primarily for use in
camouflage detection that responds to this
region which we can't see with our eyes. It
is very similar to regular Ektachrome film,
only all the bands have been shifted so that
you end up that the infrared region shows the
red dye on the film. Now this has been used
in all sorts of ecological problems. It was
used here in Denver to spot the disease on the
elm trees.

Algae floating on the surface of the water
contains chlorophyl A, is a living plant and
will reflect in this infrared region, There-
fore if you fly over a lake taking pictures
with this film, you can quite easily identify
,.. aquatic plant growth.

I

This is a picture of Rainbow Island, I
believe it is, in Lake Granby. You can't see
it in here too well but we noticed, as we were
flying over it on the way to another project,
the strange light colorations in the water
.around the shoreline. We had two cameras,
this took regular color photos and this is a
color.. infrared. You can see those red streaks.
that are in the water there. They appear to I
be streaming off from the shore in an algae
bloom, an algae concentration. We don't know
whether it starts there or if it was blown
there and then is being blown off. It is hard
to tell by the pattern. We didn't have any