The Lasso tools allow you to draw freeform segments with your mouse to create a selection border. The Lasso tools are most often used to create a rough selection (which can then be refined using techniques such as Quick Mask mode.

The keyboard shortcut for selecting the Lasso tool is the letter L. To select the next Lasso tool, press Shift+L. The following list describes each of the Lasso tools:

  • Lasso tool: Use this tool to make a freehand selection. You must return to your starting point to close the selection loop. If you don’t return to start and simply double-click, Photoshop will draw a straight line and close the selection point for you.
  • Polygonal Lasso tool: Use this tool to draw straight-edged segments for a selection border. With every click, a part of the segment is drawn. Continue clicking to set endpoints for additional segments. Click your starting point to close the loop and create an active selection. To constrain the tool to 45-degree angles, hold down the Shift key while drawing.
  • Magnetic Lasso tool: When you use the Magnetic Lasso tool, Photoshop attempts to snap the border to the edges of the image. If the anchor point doesn’t snap accurately, click once to manually add a point.

Selection options for Lasso tools

When using the Lasso tools, you have several options available in the Options bar to improve or alter your selection. These modifiers are very similar to those for the Marquee tools, so I’ll just briefly mention them.

The first four icons specify the kind of selection:

  • New selection
  • Add to selection
  • Subtract from selection
  • Intersect with selection

The next three options create a smoother selection:

  • Feather: This option creates a softer edge on your selection.
  • Anti-alias: This creates a smoother edge for curved lines.
  • Select and Mask: This button provides options to make precise selections through tools like the Refine Edge Brush.

Magnetic Lasso options

The Magnetic Lasso has a few additional options that mainly deal with its snapping behavior. You can change the following properties in the Options bar:

  • Width: The width specifies how wide an area the Magnetic Lasso looks at when trying to detect edges. To see the width visually, activate the Caps Lock key before making a selection.
  • Edge Contrast: This value determines the lasso’s sensitivity to edges in the image. Higher values detect high-contrast edges, whereas lower values detect lower-contrast edges. On an image with well-defined edges, you should use a higher width and edge contrast setting.
  • Frequency: The rate at which Photoshop adds anchor points is based on the Frequency setting. An anchor point is where the lasso attaches, so you can move the selection border in another direction. You can enter a value between 0 and 100. Higher values add more anchor points to your selection border.
  • Stylus pressure: Click the Stylus Pressure icon if you have a tablet connected. This lets you to use the pressure of the pen to affect edge width.