Priming is the process of creating a barrier between the canvas and the paint of a painting. … The primer does several things to help your artwork look it’s best and last a lifetime, and it’s surprisingly easy to do. Gesso serves as a waterproof surface that allows your paint to spread evenly across the canvas
Acrylic medium is a substance that is added to acrylic paint to change one or more of its properties, these mixtures can be incorporated into the pigment to lengthen its drying time, make it thicker, or change the texture. Mediums are bought in addition to paints. There are several types of acrylic mediums available.