Though the public likes to hold onto myths about an artist's seemingly magical ability to pluck color and form and composition solely from the depths of the imagination, painters have continually sought ways to make the purely technical problems of portraying reality easier to solve. English artist, David Hockney, did an interesting study a few years back where he searched the internet to compile thousands of digital images of portraits painted from as early as he could find up until the present. He printed them all out and pinned them to a wall in his studio in chronological order forming an elaborate time line of the history of portrait painting. He was not surprised to find that at around the year 1420, portraiture took an enormous leap towards realism. He theorized that there was no coincidence in this leap happening right around the time that the concave mirror was developed. The invention of optical lenses and later photography only propelled this leap exponentially. Is this cheating? I guess that depends on what you thought the rules were to the game that we artists are playing.