Gesso is a flat acrylic liquid primer used in the Bob Ross Wet-on-Wet Technique, when a dry pre-coated canvas is required. This water-based paint should be applied very thinly with a foam applicator (NOT A BRUSH) and allowed to dry completely before starting your painting. This 2.1x7.8x2.3 inch package contains 473ml of Bob Ross Gesso in black. Health and Safety: Avoid ingestion, excessive skin contact and inhalation of sanding dust, spray mists and concentrated vapors. Conforms to ASTM D4236. WARNING: This product contains a chemical known to the State of California to cause cancer. Made in the USA.