Oil painting primer imparts a traditional oil base. Some artists prefer this and may find a slight increase in gloss and smoothness. Oil primed canvases may slacken off less than acrylic primed canvases. A coat of warm glue size is required first. As a result of their formulation, Winsor & Newton acrylic primers are also suitable for oil painting. They are popular because they dry quickly and do not require any sizing underneath.