Can you guess what's wrong with these paintings?

Prior to the mid-20th century, art restorers took a heavy-handed approach, often drastically altering paintings in the name of "improving" art. Today, they focus on keeping the original work intact with minimal intervention, and must regularly contend with past modifications. So, how is damaged artwork repaired? Noah Charney explains the painstaking process of restoring priceless artifacts. [Directed by Michael Kalopaidis, Zedem Media, narrated by Addison Anderson, music by Manolis Manoli].