Magnetic Lasso Tool in Photoshop Elements 10 - dummies

Magnetic Lasso Tool in Photoshop Elements 10

By Barbara Obermeier, Ted Padova

The Magnetic Lasso tool works by defining the areas of the most contrast in an image and then snapping to the edge between those areas, as though the edge has a magnetic pull.

You have the most success using the Magnetic Lasso tool on an image that has a well-defined foreground object and high contrast between that element and the background — for example, a dark mountain range against a light sky.

The Magnetic Lasso tool also has some unique settings, which you can adjust on the Options bar before you start selecting:

  • Width. Determines how close to the edge (between 1 and 256 pixels) you have to move your mouse before the Magnetic Lasso tool snaps to that edge. Use a lower value if the edge has a lot of detail or if the contrast in the image is low. Use a higher value for high-contrast images or smoother edges.

  • Contrast. Specifies the percentage of contrast (from 1 percent to 100 percent) that’s required before the Magnetic Lasso snaps to an edge. Use a higher percentage if your image has good contrast between your desired element and the background.

  • Frequency. Specifies how many fastening points (from 1 to 100) to place on the selection line. The higher the value, the greater the number of points. As a general rule, if the element you want to select has a smooth edge, keep the value low. If the edge has a lot of detail, try a higher value.

  • Tablet Pressure (pen icon). If you’re the proud owner of a pressure-sensitive drawing tablet, select this option to make an increase in stylus pressure cause the edge width to decrease.

Follow these steps to use the Magnetic Lasso tool:

  1. Select the Magnetic Lasso tool from the Tools panel.

    You can also press the L key and then press Shift+L until you select the Magnetic Lasso tool. The tool looks like a straight-sided lasso with a little magnet on it.

  2. Click the edge of the object you want to select to place the first fastening point.

    Fastening points anchor the selection line. You can start anywhere; just be sure to click the edge between the element you want and the background you don’t want.


  3. Continue to move your cursor around the object, without clicking.

    While the selection line gets pinned down with fastening points, only the newest portion of the selection line remains active.

    If the Magnetic Lasso tool starts veering off the desired edge of your object, back up your mouse and click to force down a fastening point. Conversely, if the Magnetic Lasso tool adds a fastening point where you don’t want one, press your Backspace (Delete on the Macintosh) key to delete it. Note that successive presses of the Backspace or Delete key continue to remove the fastening points.

    If the Magnetic Lasso isn’t cooperating, you can temporarily switch to the other Lasso tools. To select the Lasso tool, hold down Alt (Option on the Macintosh) and then click the mouse button and drag. To select the Polygonal Lasso tool, hold down Alt (Option on the Macintosh) and click.

  4. Return to your starting point and click the mouse button to close the selection.

    You see a small circle next to your cursor, indicating that you’re at the right spot to close the selection. You can also double-click, whereby Elements closes the selection from where you double-clicked to your starting point. The selection border appears when the selection is closed.