A friend and I took a course in conservation as part of our graduate work in art history. We had to make 3 kinds of paintings: a manuscript page, an egg tempera panel, and an oil painting. The panel was tough: you had to sand it endlessly, boil rabbit skin, coat it with red bole, sand some more, add finicky gold leaf, and paint with an egg-based tempera.
Just as we were finishing after weeks of labor, my friend came to class with a sheepish look on her face, muttering to our instructor: “You know how dogs love eggs? Well, mine licked the entire coat of egg tempera clean off the panel, so all my work has vanished.”
Now I like to think that perhaps the young, struggling Duccio once similarly slinked into his master’s workshop with the world’s first “the dog ate my homework” excuse.