Photoshop History Brush
The history brush uses a previous state or snapshot of an image. The tool makes a copy of the image as it was in a previous state, then uses the content of this copy to paint with.
The example on the right shows the history palette of an image. Three things have happened (i.e. there have been three states):
- The image was opened.
- The levels were adjusted.
- A glowing edges filter was applied.
In the left column of this palette there is a selection box next to each state. Click a box to select that state. By default, the selected state is the point where the file was opened or created.
Painting with the history brush tool will add content from the earlier state like so: