Realism vs Impressionism
It is very important to understand what type of Portrait you want. Some customers choose one of each, as they are so different. Realism, is just that. The Portrait will look very similar to the Photo. It will show all detail, and be a very realistic Oil Portrait of the photo.
Impressionism is very different, as it gives you an impression of the photograph. This style is harder to capture the detail, as it's importance is simply to give the impression from the photograph. Many Customers and Artists believe this is more like an actual painting, than Realism. It is important to note that the Impression Portrait will not show perfect facial details and be as clear as a Realism Portrait.
Please note below, one of each, so you completely understand the difference.