But what if, instead of erasing a top layer to see through to a bottom layer, you could erase an image to see through to the image in the past? That's what you can do with the History Brush. When you use the History Brush, you're painting with the past.

How to use the History Brush
That's why I chose to do the autumn effect. The first snapshot is the summer shot while the second snapshot is the autumn shot. When I use the History Brush, I'll be able to paint some of the summer back, right over autumn. Here's how it's done.

First, you'll want to make sure to select the History Brush, as shown in Figure D. The History Brush is a pop-up menu. Be sure to select the icon with the arrow.

FIGURE D

The History Brush is a pop-up menu. Be sure to select the icon with the arrow.

Next, you need to select the time in the past you're going to be painting with. This is done by going to the History Palette and clicking in the little box to the left of the snapshot or history step you want to use, as shown in Figure E.

FIGURE E

Now, choose the source for the History Brush. Click picture for a larger image.

Finally, choose a brush you want to paint with and go to town. In this case, I decided I wanted to bring back some of the summer green to the grass in the foreground, as you can see in Figure F. You can see my brush in the lower, left corner.

FIGURE F

While the leaves turn, the grass doesn't yet. I wanted the green to come back to the foreground. Click picture for a larger image.

There are obviously lots more uses of the History brush, but this quick example shows how you can bring back some of the nostalgic past, or at least your earlier snapshots and use them to touch up your photographs.

Finally, I can't lay claim to figuring out the autum effect. I found that online, at http://fotofects.com/articles/93/1/Autumn, in an article by Denny Tang. It's a cool effect and you should definitely check it out.

Wallace Wang is the author of The Book of Nero 6 and Steal This Computer Book, both published by No Starch Press. Besides writing computer books, he also performs stand-up comedy, having appeared on A&E's "Evening at the Improv" and appearing regularly at the Riviera comedy club in Las Vegas.