Feature: Replace Your Background Using Layers

When I lived in Colorado, I had a glorious view of Pike's Peak and the front range of the Rocky Mountains out of my kitchen window. Indeed, the mountains were so close to town that downtown buildings loomed up in the foothills, giving you the impression that you could walk from the grocery store to the mountain itself in an afternoon.

Now that I live near Seattle, I still have a big mountain to stare at--Mount Rainer--but it is much farther away and looks not nearly so dramatic against the city skyline. This week, let me show you how I've been fixing that digitally. Then you can then apply this background replacement technique to your own photos.

Pick a Pair

For this week's experiment, I need two pictures: a skyline shot of Seattle and a picture of Mount Rainer to put in the background. Save them to your hard drive if you want to follow along.

The two pictures should do nicely for our project. They were taken moments apart, and the lighting in both scenes is almost identical. For the skyline shot, I picked a picture taken with the camera's lens set to a "normal" focal length: not zoomed in, not quite wide angle. This way, it looks about the way you'd see it with your own eyes. In the picture Rainer looks quite small and is positioned off to the right edge of the cityscape. After taking that picture, I zoomed as far as my camera would take me and captured a "close-up" shot of the mountain.

Stack the Pictures

To begin the editing process, load the picture of the zoomed-in mountain into your favorite image editing program. I'll use Jasc's Paint Shop Pro for my example.

Leave it in the background and load the skyscraper picture as a new layer. To do that, load the cityscape picture into Paint Shop Pro and choose Edit, Copy from the menu. Close that image file--we don't need it anymore--and choose Edit, Paste, Paste As New Layer. You should see the city of Seattle on top; the big mountain is hidden in the layer underneath.

Select the Background

Choose the Magic Wand tool (it lives in the fifth cubby from the top of the tool palette on the left side of the screen). For this picture, we'll need the wand's tolerance set to about 25 and the feather set to zero. These values are set in the Tool Options Palette, which you should see at the top of the screen. If you don't, toggle it on by choosing View, Palettes, Tool Options.

Now click somewhere in the middle of the big blue sky. Much of the sky should become selected right away. Hold down the Shift key and click in the parts of the sky that aren't selected. Holding down Shift "adds" your selections together. It should take about five or six clicks in total, including one in the middle of the little Mount Rainer.

Transplanting a City

Now for the fun part. When the selection is complete, press Delete on your keyboard. The entire sky will disappear, dropping Seattle about 50 miles closer to Mount Rainer. Save the image and you've successfully altered reality.