Acrylic Wash Portrait

Every week I go to a sketching club where I practice to paint. This picture shows the same model painted by me 14 months apart. The one on the left is when I started trying to paint in acrylics, and the one on the right is when I have become a lot better at it! Sorry about the wrinkled paper, I never did buy any better quality paper to paint on (this is just a scrap paper notebook bought in a supermarket, not proper artist's material!)