Anima

I’ve skipped past the History Brush in Photoshop for years. Today I stumbled across 3 cool uses (and was then frustrated that I couldn’t find any quick youtube tutorials on it). Also, recorded a quick camtasia video, to practice the process.
http://youtu.be/y-S9B5Bwles

1. Erasing
Often you want to draw over existing lines, but then find it hard to erase the new slop without ruining the old existing lines. I used to draw these “crossing over” lines in a new layer, carefully erase them to the middle of the existing lines, then merge down. but you can do it all way faster/easier with the history brush.

Set a reference point before your crossover stroke, then drawing will erase that new slop to match “history”.

2. Replacing
Maybe I should just call this one “smooth cornering” or “making sharp joints.” Often when two lines meet, you want to tweak one of them, and it messes up the other. Well, you can replace (or “re-fill”) the other line by setting your history point to a time when the other line was un-muddled. Then change the History Brush “Mode” to “multiply”. Now your strokes will be additive (adding in the old perfection, instead of erasing the new stuff).

3. Stylizing
Once you’re done with your line work, you can quickly spice it up. Set the history ref point at the current (final) frame. Then either jump back to a history point before all the art, or erase everything. The idea is to start over from a blank slate, and quickly fill in most/some of the final work.
You’ll easily recreate that final art with some style. Maybe draw across the strokes, to make it look like you have amazing control. Or use weird textured brushes to make it look like you have amazing edging control/masking.

The cool thing about this trick is that it can be reused infinitely. Each new spiced up state can be set as a new history ref point, and spiced up again.

Hope this all is of interest. I imagine you could also do some cool stuff with this tool when working with color. But I’m not very experienced in color! So I leave that to you to suggest in the comments.