How to Use the Photoshop Background Eraser Tool

This article explains how to use the Background Eraser Tool to remove the background from an image in Adobe Photoshop.

How to Erase a Background With the Background Eraser Tool

To start this project we opened an image of the jets and another shot out of the window of a flight we were on. The plan is to make it look like the jets are zooming past our window.

We selected the Move Tool and dragged the jets image onto our window seat image. We then scaled the jets down to fit the upper left corner of the image.

We then selected the Jets layer and used these settings for the Erase Background tool. (If you can't find it, press the E key.):

• Brush Size: 160 pixels
• Hardness: 0
• Sample Once option is chosen
• Limit: Contiguous
• Tolerance: 47%
• Foreground Color Protected

From there it was a simple matter of erasing the blue sky. We also zoomed in on the planes and reduced the brush size to get into the small spaces. Keep in mind, that every time you release the mouse, you will need to resample the color to be removed. Also, the crosshair is your best friend. We ran it along the edges of the jets to keep the edges sharp.

It may take a little time experimenting with the background eraser tool options before you can achieve these results quickly, but with a little practice, we're sure you'll start to see the power of this amazing tool.

The Background Eraser Tool Options Explained

When you select the Background Eraser Tool the Options change. Let's examine them:

• Brush: Set the Brush Size, Hardness and Spacing options here. try keeping the Hardness around 0 to have a nicely feathered edge.  Smashing Magazine has an excellent article explaining the Brush settings.
• Sample Options: The three eyedroppers do different things. The first one is Continuous Sampling. That means any color under the crosshair in the brush will be turned transparent. Sample Once will sample a color you click and will remove only that color until you release the mouse. Sample Background Swatch will make whatever color you click the Background color and, as you paint, only that color will be removed.
• The Limits has three choices in the drop-down. The first is Discontiguous which means the brush will erase any of the color being painted over that the brush finds. Contiguous is great for fine detail because it will remove the sampled color but any colors not matching are ignored. This is ideal for hair. Find Edges will stop the color removal at the edges of a sample area. Again, this great for fine detail work.

• Tolerance: This usually defaults to a value of 30. What it means is the higher the tolerance, the more of the surrounding hues and colors will be removed.
• Protect Foreground Colour: If you look at the above image, you will see the jets have a bit of blue in them and we don't want to accidentally have that blue removed. To do this, double-click the Foreground color and sample a color you wish to protect.

What Is the Background Eraser Tool?

The Background Eraser Tool in Photoshop is an extremely useful tool. The pros use it to isolate fine detail, like hair, in photos but it can be used for more general purposes. Still, there are a couple of things you need to know before you start merrily erasing backgrounds.

• It is a "destructive" editing tool. The changes you make are applied to the original image, even if it is a Smart Object, and once a background is gone ... it is gone. Always work with a copy of the original image or duplicate the background layer and work on the duplicate.
• Try having the background of the image to be erased as close to a solid color as possible. This tool is a brush and it will sample color within the brush boundaries.
• Get familiar with making a brush larger or smaller to "paint over" large and very small areas. The keyboard command for a larger brush is the ] key and for a smaller brush, press the [ key.
• If you make a mistake, press Command/Ctrl-Z to Undo or open the History panel — Window > History — to go back in time. If you really mess up, delete the copied layer and start over.