This is done simply with the brush tool.

这用笔刷工具很容易操作。

youdao

Select the Brush Tool, set the diameter to 400 pixels.

选择画笔工具，设置直径为400像素。

youdao

Select the brush Tool (b) right click on the image and select the brush we just made.

选择画笔工具(乙)在图像上点击右键并选择我们刚刚刷了。

youdao

You then 'paint' the color back in using a brush tool, restoring the original colors into the areas of the photo that you want to.

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Nasa's Mars rover Curiosity has used its brush tool for the first time to sweep dust off the surface of a rock.

BBC: Curiosity Mars rover deploys its rock brush

That latter tool, the Advanced Healing Brush, lets you paint in corrections, rather than using the round dropper to make tweaks.

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