Leonardo was obsessed with problems like how to create translucent effects in painting, how to capture the mysteries of light - the very problems posed by painting a glass sphere.

达·芬奇沉迷于像如何在画中营造半透明效果、如何展现光的奥秘——这正是画一个玻璃球要面对的问题。

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When a painting becomes an icon, a psychological semi-translucent veil is placed over the work that partially obscures it from us.

BBC: Too famous to see?