There's more to painting a great portrait than capturing a likeness; it's about creating the illusion of life. Portraiture should reveal the character of the sitter and exude a lifelike essence. (From an article about a classical portrait painting class Marvin Mattelson teaches / taught in 2013; http://underpaintings1.rssing.com/chan-10103856/all_p7.html ; you have to scroll down to find it.)