There is quite a process for getting your support ready for a painting. When I work on masonite board it requires several coats of gesso. Each coat of gesso has to dry before applying the next coat. After several layers of gesso I give it a light sanding to remove any imperfections resulting in a smooth white base ready for applying acrylics. I apply acrylics in washes which needs the absorbent base that the gessoed masonite board provides.