Other options to restore the frescoes would have required using chemicals to remove the unwanted layer or using physical means to scrape it off.

其他修复壁画的方法可能需要使用化学物质来去除不需要的层，或者使用物理方法将其刮掉。

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As these functions use stack semantics, you can layer transformations for shapes and later remove them to restore the original matrices.

由于这些函数都使用堆栈语法，所以您可以对形状应用层次转换，并在后面将它们删除，以恢复原有矩阵。

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The above steps reduce the contrast slightly too much, so we restore this with another blended in grayscale layer to up the contrast but leave the colors relatively unchanged.

前一步让对比度下降的有点大了，所以咱要再一次用一个灰度图来加大一点反差，但要保持色彩关系不变。

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