A bottom-weighted mat is one where the border below the image is wider than the borders above and beside it. This technique is used both for aesthetic and functional reasons. When an image has darker colors, larger shapes, or more texture or pattern in the lower half than it does in the upper half, it can look like it is sinking into the mat once it is framed. By increasing the width of the lower mat border, the completed piece looks more balanced. If the image itself has a larger margin below than on the other sides, it is necessary to bottom-weight the mat in order to avoid cutting the art.
