Jurgen Wolff reports:
One of the reasons that David Hockney has kept the attention of the art world is that he's open to trying new things.
For a while, he experimented with Polaroid pictures taking advantage of the fact that for a short time after the picture came out of the camera you could squish and squash it to distort the image.
Now the 73-year-old has been using his iPhone and an app called Brushes to create original artwork.
The New York Review of Books reported in 2009, "Over the past six months, Hockney has fashioned literally hundreds, probably over a thousand, such images, often sending out four or five a day to a group of about a dozen friends, and not really caring what happens to them after that."