What is an underdrawing?

What equipment is necessary to do an acrylic painting?

To paint in acrylic, you should first determine if you're painting alla prima (attacking the surface with a loaded brush and no underdrawing) or using a more classical (and commonly illustrative) approach, building up, thin-to-thick layers over a drawing made directly upon the canvas or board. In either case, you'll need a set of brushes of varying size and shape, (Synthetic bristle brushes are not only affordable, but ideal for acrylics) some jars or cans of water, to thin down paints and clean out brushes, a palette to hold and facilitate mixing of paints. (Some use palatte knives to mix and to scrape paint off of the surface when necessary. A butcher tray lined with wet paper towels, then topped with a piece of tracing paper makes for a long-lasting palette, easily covered with plastic wrap and stored indefinitely in the refrigerator.) Just about any soap is good for keeping your brushes clean. You'll need some paints. Duh. Then, you'll need surfaces. Canvas, illustration board... even cardboard primed with gesso or cheap house paint can serve as a decent surface for painting. Some rags or paper towels will come in handy for reasons that are plainly self-evident. Then, you'll need a subject: a friend, photo, object or idea that you wish to paint. If you're going for the illustrative approach, you may need transfer paper to get your tight final drawing onto your board. You may also want to use a hair dryer to speed up the building of thin layers. Okay, have at it!