Adobe Photoshop CC 2014 v.14.xx - Manual (Page 481)

checkbox (found in the options for the Spot Removal tool), the image is inverted. You can then use the Spot Removal tool in the Visualize Spots
mode, to clean up the image further.
The Visualize Spots checkbox is a Spot Removal tool option
1. Do one of the following:
Open a camera raw file, or,
With an image open in Photoshop CC, click Filter > Camera Raw Filter.
2. Select the Spot Removal tool from the toolbar, and then select the Visualize Spots checkbox.
The image is inverted, and the outlines of the elements of the image are visible.
Below, Visualize Spots view is on, and unnecessary elements like wispy clouds (left) have been removed (right)
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