|Mile 51.8 Dec. 1962
Approaching Dove Canyon (left bank).
|Dec. 1962 The landing at
Dove Canyon is about a mile upstream of West Canyon Creek. That's
Gregory Butte looming over West Canyon Creek.
|The exploration of Dove Canyon starts
with a long swim.
|Dec. 1962 This is one of the finest
of the long narrow canyons. As we walk up further and further, the light
intensity gets less and less. The camera must be on a tripod for
most of the pictures and a rather long exposure -- perhaps as much as three
minutes -- is needed. This results in blue pictures, and we came
to know these canyons as "the blue canyons."
|The predominance of blue
is the result of "reciprocity failure" in the emulsions of the film (Kodachrome):
as the light gets very dim the responses of the three emulsions in the
film no longer follow a simple linear relationship of image density to
exposure time. The red and green sensitive layers are most affected
by reciprocity failure -- twice the exposure time does not result in half
the density of the transparency. The film is relatively "blind" to
the red and green ranges of the spectrum. The blue-sensitive layer
retains much of the reciprocity relationship, so its response is still
pretty good. The blue image remains while the red and green images
are largely gone.
in Dove Canyon
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