Notice the angel's eyes. She's focusing on Isaac, as if to make sure he was unharmed. Isaac glorious youthfull body in perfect submission. Eyes carefully protected by his father. You can see the wood for the sacrificial fire stacked underneath Isaac's body. Characters in the foreground, heaven and hell on the background. Tiny blue open sky on the angel's side, dark clouds on the other. The only bright spot is Isaac's luminous young body. Colors on the dark side, not a very happy picture?