To me, it's strange for a survey of one artist's work to be emotionally overwhelming--but the Renoir show at the Morgan is moving in the way that a good film is moving. You see approximately fifty years of one person's work. As Renoir ages, his arthritis makes his career difficult. But he doesn't give up; he starts using red chalk, which is apparently easier for his hands. Then he moves into sculpture--he collaborates. The collaboration lets him keep an eye on his health. It would be impossible to give up. I have been interested in Renoir since taking a trip to Paris when my son was very little. Staring at Renoir's many images of his own children, I understood that the artist was mainly compelled by the idea of different kinds of flesh. He wanted to show how the light hits a child's cheek--and how it hits a mother's cheek. The light behaves in different ways in different contexts. That one apparently small observation can be the "reason" for maki...