The final finish

When do you see or decided you done with a painting ?.when do you feel like its the last finish on a painting . I always have the same problem every time , because I believe painting is unending project in a way that there is always something more I can do better or more. Recently i have been working on two painting at once since the keeper "my new tiger " needs more time and patience which sometimes I don't have. The other painting was Kim Larsen for one of my friends ,which I had begun more ago and never got to finish it. Its always hard to stop myself but when I think about what I have achieved during the painting then i get to stop and be happy for what I have done . The final finish is when I sign my name on the painting , always in silver and my name.