How did the works of jan van eyck and rembrandt reflect a human-centered naturalism?

Human-centred naturalism is the idea that individuals and everyday life are effective and convivial vehicles for artistic expression; in particular, both Flemish painters portrayed figures in visceral poses, conveying raw human emotion through the use of a rich, deep palette with highly contrasting colors. They were both noted in Renaissance art and painted in unique manners, which are noted throughout art history as being "masterful" works of art.

Fine until slavery ya ya haha

Why do you have to ask such hard questions.