CHAPTER 9 HOW SOFTWARE CHANGES PIXELS BY THE NUMBERS^157
This was done to the picture on this page,
but we also see that the curve was moved
slightly to the right and tilted in that direc-
tion. This has the effect of boosting the mid-
tones, bringing out the color in the uniform
and in some of the fish.4
When the color scale was stretched out to
fill the range from 100% black to 100%
white, the software recalculated the color
values of some of the pixels to incorporate
the new values into the photograph. The
change expands the photo’s dynamic
rangeso that more areas of the spectrum
are represented.5
The software can alter the color of an image
by changing the histogram curve. For
instance, moving the endpoints on the left
and right toward each other increases the
contrast. This sets the brightest point to white
and the darkest pixel to black and scales
the pixels in between.3