When I asked newsletter readers to send me their questions, one of the most common was "how do I know when my painting is done?" A few of the correspondents explained that they had no problem with initially playing or experimenting with paint, but didn't know how to push the painting further. One artist said she had a pile of canvases that were almost done but somehow she couldn't call them finished.A few thoughts spring to mind:It's much easier to know when something is finished if you know your intention. If we set off on a car journey together with no destination in mind, how will we know when we have arrived? We might wind up finding a good spot by accident but it's more likely that we'll drive around aimlessly and eventually just come home without seeing anything interesting. It's the same with painting. If you are simply playing with paint, without any intention for the piece, it could go on forever. There's a chance you'll get something good by accident, but it's more likely that you'll just go on and on, never knowing when to stop.You don't need to start with an intention necessarily, but at some point, you do need to decide what the painting is going to be about. You might start that way (I want to make a painting that feels like being by the ocean) or you may find your painting's purpose part way through (I love the way this red looks against that light green ... I will make that the focus) - but until you have an intention for the piece, how can you judge when it's finished?Accept that no painting can do it allIn my current series, I am interpreting the nature poetry of Ted Hughes and creating abstract pieces based on his words. If I try to make any one painting convey everything that I want to say, it is doomed to failure. Instead, I accept that each painting will be a small piece of a larger story. In this one, I might succeed in capturing the feeling of wind. In another one, I might manage to convey emotion. But none of them will do it all - and they don't have to. There is no such thing as a perfect painting.Stop when nothing else is niggling youSo if you accept that you can't do it all in one painting, how do you know when to stop?I stop when nothing else is niggling me ... I stop when I am happy to look at all parts of the painting and there's no little voice telling me to just tone something down or lighten an area or change a colour or remove that fine line ... these niggles can be tiny but I have to address each one before I feel the painting is done.Accept that this is the best you can do for now ... but that there will be other paintings!Perhaps you can't call a painting finished even after nothing is niggling you. Often that's because we secretly feel that we could do better? The truth is that we can do better. One year from now, you will be making work that is better than the work you are making now. A year later, the same thing. But if there is nothing left niggling you, call this one done and move on! Accept that it is the best you can do for now and know that things will grow and develop.So that's it, my 4-step approach to finishing paintings. If you are an artist, I'd love to know how you decide when your work is done. Just drop a comment below!If you'd like to read more from me, you can sign up for my weekly artist newsletter.Every Sunday, I sent out a short bulletin packed with inspiration, ideas and advice. Sign up here.