A few weeks ago, I went to see a painting in Branford, Connecticut. The owners live in a large house surrounded by woods. The picture is a fine copy of an early seventeenth-century portrait by Anthony Van Dyck. From my precarious vantage point on top of a wobbly stepladder, the canvas appeared to be machine-woven, which means that it cannot have been made, or paint applied to it, before the 1820s. Fortunately, the owners already know this, and are philosophical.