People have asked if there is a polite way to approach a plein air artist while the artist is out painting.
Unless the artist is on a deadline to complete the painting, most artists will welcome your interest in their work. That being said, you can’t possibly know without breaking the artists concentration.
If you want to see the finished painting…
If you would like to see the finished painting, hand the artist your email address and request an image of the completed painting. Most artists will appreciate you being considerate of their work time and happily send you an image, or give you the name of a gallery where the painting will be exhibited. Hope this helps! – Catherine