★★★★★
A wild man glares from behind the glass. How dare a curator cage this scowling creature with ivy twined in his hair and a pelt across his shoulders? Drawn by Leonardo da Vinci he is hardly larger than a paperback cover yet done with such exacting attention you can trace every tendril and wrinkle. If you’re wondering how any artist — even the mighty Leonardo — could conjure such effects with red chalk, a display case in the next room of Drawing the Italian Renaissance at the King’s Gallery offers the explanation. Banish thoughts of modern pavement or blackboard chalks capable of only the bluntest of lines. Red chalk, a naturally occurring mineral, could be cut into small shafts, sharpened to a point for