CHAPTER 9 HOW SOFTWARE CHANGES PIXELS BY THE NUMBERS^155
You can best see how your software
creates the new pixels by looking at the
pixel level. This simple image is made
up of only 4 pixels. We’ll perform a
five-fold enlargement, bigger than
most, but good to illustrate the process.(^2) First, the software spreads the exist-
ing pixels apart.
(^3) Next, it fills in the white space with
duplicates of the existing pixels.
4
Leaving the photo like
this will result in a
blotchy-looking image.
To prevent this, the soft-
ware uses one of many
algorithms to create
transition among the
original colors.
5
The software might then
perform a Sharpen
process (as described
earlier in this chapter),
which will give you
something like this. The
software can also apply
a blur for a different
effect.
6
Better Ways to Enlarge Images
If you want to enlarge your image substantially,
it’s better that you do it in a series of small
increments of no more than 110% at a time
until you reach the desired size. The reason is
that your image editor will have smaller gaps to
fill in after spreading the existing pixels and
your final result will look much smoother than if
you tried to make a substantial enlargement in
one pass. Think about it this way: It’s easier to
walk up or down a flight of stairs one step at a
time. You can probably skip every other step
without too much of a problem. But things will
be more difficult the more steps you try to skip
on your way up or down.