If you look very closely at the large version of the final piece, there are a couple of tiny areas that give away the fact that it isn't a photograph. The inside corner of the model's left eye (the right eye as you view the piece) and the gumline of the sixth tooth to the right are two of them.
It's an amazing, fantastic piece, though, that requires a tremendous amount of skill to execute. I haven't seen this level of skill in an airbrush artist before.
Why do it? I'm surprised anyone would ask that question, honestly; the answer seems obvious to me. Because it is a way to hone your technical skill to a fine edge. High degree of technical skill is an enormous asset for creating any kind of art; it is the artist's vision that conceptualizes the art, but it is the artist's technical skill that allows the artist to get the vision from his head into the outside world. The greater the technical skill, the more easily the artist can create anything he can imagine.
Leonardo da Vinci and Michalangelo both spent a tremendous amount of time sharpening their technical skill. Da Vinci did anatomical drawings over and over again, so that he could more realistically portrey the human form in whatever position he could imagine. Michaelangelo created detailed sketches of his sculptures and artwork, often drawing from real-life subjects, before he executed the final piece; this allowed him to create
exactly what he wanted.
The web site even says:
QUOTE
After some deliberation, I decided to test the limits of my visual skills by completing the project painting. The realism of almost all of my previous paintings was compromised by time constraints and deadlines, but I imposed no deadline on myself this time.
In other words, this piece is not intended as "Art," it's intended as a test of the painter's own level of skill.