nigredo

例句：

1. 2.
   油画、素描等的
2. 3.
   指人或物因长时间暴露在阳光或灯光下而显得深色
3. 1. The artist applied a nigredo to the canvas.
   艺术家给画布上涂了一层深色调。
4. 2. The old man's face was covered in nigredo from years of sun exposure.
   老人的脸上被岁月晒成了深色调。
5. 3. The painting has a nigredo that adds depth and texture to the scene.
   这幅画有一层深色调，为场景增添了深度和纹理。