CHAPTER 9 HOW SOFTWARE CHANGES PIXELS BY THE NUMBERS^145
When you tell your image editing software
to make a change, such as sharpen,
brighten, or apply effects, the software
looks at the differences in color between
pixels. Often, it compares those values
with pixels that are close but not touching
the pixels under scrutiny.3
Zoom in far enough, and you see
that each pixel is actually a tiny
square consisting of a single,
solid color.2
The software applies a mathematical formula to recal-
culate the color of each pixel. It starts with the formula
for the type of editing or effect you are asking it to do.
It also takes into account the differences in color
between pixels, often those in or near transition areas.(^4) Not all pixels are changed equally. Some pix-
els might retain the same general color but take
on a slightly darker or lighter tone. Other pixels
might be assigned a very different color. Pixels
that are not near a border area might not be
changed at all.
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