As the name suggests, milk paint is a water-based paint that uses milk as a binder instead of polymers or oil, which are used in latex or oil-based paints. Yes, that means it has a shorter shelf life than those paints. But when pigments are added to milk paint, the colors are rich and earthy and the luster is somewhat translucent—perfect for achieving an antique finish.
I've seen some beautiful furniture projects finished with milk paint, but I've yet to try it out myself. With milk paint selling for as much as $50 bucks a gallon, I've leaned toward saving a few dollars going with regular old latex paint. However, latex or enamel paints aren't known historically for being the most environmentally friendly products, to put it mildly, so it's understandable why some people with the means are willing to pay a premium for a "green" paint product.
For more about greener paints, check out Remodelista's post on the subject.
Tim Layton is a home and DIY blogger for Popular Mechanics. Follow him on Twitter: @RemodelingGuy