Portrait painting is the art of constantly making corrections.  I tell my students not to be discouraged if they notice an error and are afraid to make these changes.  I try to help them realize that as portrait artists, they must constantly be on the look out for minute marks that are trying to veer away from the likeness or expression. We should be examining and adjusting the position and measurements of our features all the time. If we don’t do this, then in the end, when we take a new perspective, we will see a glaring problem and it may be too late!