174 PART 3 HOW THE DIGITAL DARKROOM WORKS
How Digital Photos Make Fun of You
Raising a young boy to be a man is no easy chore—unless you have morphing software. Morphingconverts one image into another in a
number of discrete steps, each of which is a blend of the characteristics of both. Although there are many mathematical methods of morph-
ing, the basic procedure is a combination of two techniques: cross dissolving and warping.
Cross dissolvingis the same technique used in
slideshows and PowerPoint presentations: One
image fades out while another fades in. A com-
puter producing the effect begins by holding both
images in memory simultaneously as it displays
the first image.1
The morphing software randomly chooses some of
the pixels in the first image and replaces them with
the pixels from the same positions in the second
photo. It repeats the process until it replaces all the
original pixels. This gives us a dissolve, a common-
place feature of any movie. But it’s not yet a morph.
It needs to warp as well.2
In one common warpingmethod, the user manually places dots on one face and part-
ner dots on the other face to identify major features, such as the nose, mouth, and eyes.
The more pairs of dots used in the warp, the more realistic the result. The program here
uses a variety of colors for the dots to help the user keep track of what’s been done.3