Pascal Cotte said da Vinci built the painting up in layers, the last being a special glaze whose optical properties increased the illusion of a three-dimensional face.

• 帕斯卡尔?柯特称，达芬奇在绘制这张画时使用了多层颜料，最表面的一层使用了一种特殊釉料，这种颜料的光学性能可增加人物面部的三维效果。