Alex Katz refuses to slow down. At ninety years, Katz can still surefootedly drag a 12-foot wet line across an enormous canvas with an outcome so crisp and faultless, it seems to eschew human intervention. In a series of new works, currently on view at Gavin Brown, he intensifies the yellow of a Maine sunset and plays with skin and hair tonalities: chocolate brown, biscuit-white, and milky-cream vs. oatmeal, ebony, and henna red.  Aside from a few magnificent landscapes and a couple of smaller cityscapes, his new billboard-like compositions examine multiple figure configurations; either full-scale or in variations of his signature cropped face format. Saturated with surface energy, they display an intensity and clarity that transcends art trends and that has cemented his place in art history among the foremost American post-war artists. At GBE through December 22.