When you use the History Brush, you’re painting with the past.

Photoshop and its little brother, Photoshop Elements, are amazing tools. They're also amazingly complex. In fact, you can use Photoshop for years without ever tapping its full potential. In our new Photoshop Secrets series, we're going to take one small feature of Photoshop per article and help you understand what it does. This week, it's the History Brush.

To understand the History Brush, you first have to understand how Photoshop handles history. You've probably discovered the History Palette, shown in Figure A.

The History Palette records two types of information. As you can see in the above figure, at the top of the History Palette are snapshots. In this case, we have two snapshots, one of the original image with some improved saturation and one called "Autumn Leaves". You'll see what we're doing with the autumn leaves in a minute, so stick with me.

In the lower section of the History Palette, you can see I did a number of color management procedures. The lower section records a series of steps and lets you step back, one step at a time, to see everything you've done.

Before we go on, let's look at an image from my "Wow, I have a digital camera, let's shoot some stuff" collection. Figure B shows a lovely shot of some trees and a walkway sometime in the fall.

Notice that this image appears to be taken in autumn. You can see the yellowed leaves. But I put them there with Photoshop magic. The snapshots in the History Palette now make more sense. The first was an original image with green leaves and the second is the one with all leaves turning colors.

For the record, the actual photo I took is the one in the "Better Saturation" snapshot, shown in Figure C.

What made the autumn effect seem all the more real is that there were already some leaves on the path. So even though the first one was taken in the summer and there were just leaves there (there always are, on this path), it's easier to make it seem more like autumn.

But this time, we're not talking about colorizing effects. Instead we're talking about the History Brush.

This might help make the History Brush more understandable. First think about layers. When you work with layers, you're working with images stacked on top of other images. If you erase part of a layer, you can see through to the lower layers.

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.

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.

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.

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.