I believe it's a hue but I'm not 100% sure. Sorry.
Answer:
The painting is called the Last Supper and it is by Leonardo da Vinci. The painting represents the scene of the Last Supper of Jesus with his apostles, as it is told in the Gospel of John, 13:21. Leonardo has depicted the consternation that occurred among the Twelve Apostles when Jesus announced that one of them would betray him.
