Also known as ‘direct painting’, ‘au premier coup’ or occasionally mistakenly as ‘wet-on-wet’, alla prima is a one-layer painting technique in which the painting (usually painted from life) is completed in one sitting or while the paint is still wet. The term derives from an Italian phrase meaning ‘at first attempt’. It is mostly commonly used in oil painting, and is not suited to painting with acrylics because of their faster dry time.
While there is some overlap between alla prima and wet-on-wet painting, the terms are not synonymous. Alla prima always involves wet-on-wet painting, but it is possible to paint wet on wet without completing the entire piece in one sitting, which is what alla prima entails.