To comply with the lights direction we have to make the "top" layer lighter and the "bottom" layer darker.

为了遵守光的方向，我们必须使“顶部”层打火机和“底”层暗。

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Finally, set the blend mode of the colorized layer to "Overlay". This will help blend the color into the image and let the darker line work underneath show through.

最后，将颜色图层的混合模式设置为“叠加”。这将帮助把颜色融合到图片中，并让暗色的线条在下面显现出来。

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If necessary make the top layer a little darker.

如果需要可以使顶层变暗一些。

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