I painted Albert Einstein in full color. Here he is giving a lecture in 1921

 Albert Einstein Giving a Lecture. 40x30 inches. Oil on Linen. 

The formula on the board is what is preserved on a black board Einstein used in Oxford. 

Print available here: https://www.inprnt.com/gallery/pavelsokov/albert-einstein-giving-a-lecture-in-1921/

This writing comes from Einstein's Blackboard at the Museum of the History of Science in Oxford