Oil painting is a very old and very well known form of art.    Colors blend beautifully and many subtle transitions are possible, as well as glazes and textures.   It takes a while to dry.   It is usually, but not always, varnished.   Oil paintings may be cleaned, preferably by a professional.

Acrylic painting (of the fine art kind) is a more recent development - not all that recent, but neither is it from the Renaissance!    It is a water-soluble paint that dries relatively quickly and is very versatile.   It is a variant of, but not the same thing as, acrylic house paint which you may have used.   It is especially suited to works with heavy texture and bright coloring, though quite subtle effects can also be achieved.   It may or may not be "varnished" depending on the look desired.   Acrylic paintings may also be cleaned, carefully please.

Mixed-media paintings are just what the name implies - two or more kinds of paint or other material.    Among our artists the most common is an acrylic/oil combination.   The oil must go in the top layer.    Sometimes acrylic is used as a base coat.   Sometimes the two paints are in different areas (see #1244 which is a collaboration of two artists, one painting the flower in oils and one the heavily textured background in acrylic).   Mixed-media paintings can also contain other things, such as a piece of leather.