The goldfinch in Christ’s hands became a symbol of the Passion because it eats thistle seeds (likened to the Crown of Thorns). In contrast, the fly became a symbol of evil in the Middle Ages because of its association with the Black Death. But this painting is not only remarkable for symbolism.A panel painting (such as this one) involves a lot of work. A dried-out plank of wood is layered with several coats of size, a glue made from animal skins. A piece of linen soaked in more size is laid over the front of the panel if necessary, to conceal surface flaws. Over this, the artist applies coats of gesso, a mixture of gypsum and animal glue.
Next, any areas to be gilded—such as the filigree on this Madonna’s mantle—are prepared with a layer of bole, a reddish clay. Sheets of pounded gold are applied, smoothed, and polished. Finally, the panel is ready to be painted. Crivelli used egg tempera paint, which needs constant attention to maintain a proper degree of oiliness. The complexity of the process reveals a level of devotion difficult for some modern painters to imagine: few modern-day artists slave to create a Madonna.
