Select with the lasso tools

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Adobe Photoshop User Guide

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Applies to: Adobe Photoshop

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Select with the Lasso tool

The Lasso tool is useful for drawing freeform segments of a selection border.

  1. Select the Lasso tool , and set feathering and anti-aliasing in the options bar. (See Soften the edges of selections.)

  2. To add to, subtract from, or intersect with an existing selection, click the corresponding button in the options bar.
    Photoshop Selection options
    Selection options

    A. New B. Add To C. Subtract From D. Intersect With 
  3. Do either of the following:
    • Drag to draw a freehand selection border.
    • To switch between freehand and straight-edged segments, press Alt (Windows) or Option (Mac OS), and click where segments should begin and end. (To erase recently drawn straight segments, hold down the Delete key.)
  4. To close the selection border, release the mouse without holding down Alt or Option.

  5. (Optional) Click Select and Mask to further adjust the selection boundary. 

Select with the Polygonal Lasso tool

The Polygonal Lasso tool is useful for drawing straight-edged segments of a selection border.

  1. Select the Polygonal Lasso tool , and select options.
  2. Specify one of the selection options in the options bar.
    Photoshop Selection options
    Selection options

    A. New B. Add To C. Subtract From D. Intersect With 

  3. (Optional) Set feathering and anti-aliasing in the options bar. See Soften the edges of selections.

  4. Click in the image to set the starting point.
  5. Do one or more of the following:
    • To draw a straight segment, position the pointer where you want the first straight segment to end, and click. Continue clicking to set endpoints for subsequent segments.
    • To draw a straight line at a multiple of 45°, hold down Shift as you move to click the next segment.
    • To draw a freehand segment, hold down Alt (Windows) or Option (Mac OS), and drag. When you finish, release Alt or Option and the mouse button.
    • To erase recently drawn straight segments, press the Delete key.
  6. Close the selection border:
    • Position the Polygonal Lasso tool pointer over the starting point (a closed circle appears next to the pointer), and click.
    • If the pointer is not over the starting point, double-click the Polygonal Lasso tool pointer, or Ctrl-click (Windows) or Command-click (Mac OS).

  7. (Optional) Click Select and Mask to further adjust the selection boundary.

Select with the Magnetic Lasso tool

When you use the Magnetic Lasso tool , the border snaps to the edges of defined areas in the image. The Magnetic Lasso tool is not available for 32‑bits-per-channel images.

Note:

The Magnetic Lasso tool is especially useful for quickly selecting objects with complex edges set against high-contrast backgrounds.

  1. Select the Magnetic Lasso tool.
  2. Specify one of the selection options in the options bar.
    Photoshop Selection options
    Selection options

    A. New B. Add To C. Subtract From D. Intersect With 

  3. (Optional) Set feathering and anti-aliasing in the options bar. See Soften the edges of selections.

  4. Set any of these options:

    Width

    To specify a detection width, enter a pixel value for Width. The Magnetic Lasso tool detects edges only within the specified distance from the pointer.

    Note:

    To change the lasso pointer so that it indicates the lasso width, press the Caps Lock key. You can change the pointer while the tool is selected but not in use. Press the right bracket (]) to increase the Magnetic Lasso edge width by 1 pixel; press the left bracket ([) to decrease the width by 1 pixel.

    Contrast

    To specify the lasso’s sensitivity to edges in the image, enter a value between 1% and 100% for Contrast. A higher value detects only edges that contrast sharply with their surroundings; a lower value detects lower-contrast edges.

    Frequency

    To specify the rate at which the lasso sets fastening points, enter a value between 0 and 100 for Frequency. A higher value anchors the selection border in place more quickly.

    Note:

    On an image with well-defined edges, try a higher width and higher edge contrast, and trace the border roughly. On an image with softer edges, try a lower width and lower edge contrast, and trace the border more precisely.

    Stylus Pressure

    If you are working with a stylus tablet, select or deselect the Stylus Pressure option. When the option is selected, an increase in stylus pressure decreases the edge width.

  5. Click in the image to set the first fastening point. Fastening points anchor the selection border in place.

  6. Release the mouse button or keep it pressed, and then move the pointer along the edge you want to trace.

    The most recent segment of the selection border remains active. As you move the pointer, the active segment snaps to the strongest edge in the image, based on the detection width set in the options bar. Periodically, the Magnetic Lasso tool adds fastening points to the selection border to anchor previous segments.

  7. If the border doesn’t snap to the desired edge, click once to add a fastening point manually. Continue to trace the edge, and add fastening points as needed.
    Photoshop Fastening points anchor selection border to edges
    Fastening points anchor selection border to edges

  8. To switch temporarily to the other lasso tools, do one of the following:
    • To activate the Lasso tool, hold down Alt (Windows) or Option (Mac OS), and drag while pressing the mouse button.
    • To activate the Polygonal Lasso tool, hold down Alt (Windows) or Option (Mac OS), and click.
  9. To erase recently drawn segments and fastening points, press the Delete key until you’ve erased the fastening points for the desired segment.
  10. Close the selection border:
    • To close the border with a magnetic segment, double-click, or press Enter or Return. (To manually close the border, drag over the starting point and click.)
    • To close the border with a straight segment, hold down Alt (Windows) or Option (Mac OS), and double-click.

  11. (Optional) Click Select and Mask to further adjust the selection boundary.