Keith Richards is one of the most well known and longest working guitarists. Known often as 'the human riff' and primary song writer for the stones along with Mick Jagger, he has a often very simplistic style of playing.
But his skill comes in not seeing the image of what we think of as 'Keith Richards' but when we just listen. So as a result I felt the best was to portray this was a painting that can only be seen by not looking at it. Its painted as a negative image so that it can only be truly seen when stared at for a long period and then by looking at a blank wall. So just like the man himself, you only see it when your not looking at the source.