How to Use the Magnetic Lasso Tool

In this handy guide, we've shared how to use the Magnetic Lasso tool to make precise selections, with the power of Photoshop on your side. 

What is the Magnetic Lasso?

Unlike the standard Lasso tool (which makes fairly imprecise selections by dragging your cursor around a subject), the Magnetic Lasso tool analyzes the closest edges to your lasso, and then moves the selection to those pixels automatically. These "magnetic" properties make the Magnetic Lasso a unique mixture between the Quick Selection and Pen tools. 

So how does Photoshop know where your lasso selection should be? Essentially, the software measures the closest edge to your selection, by determining the contrast, texture, and other properties of the surrounding pixels. Sometimes the Magnetic Lasso gets it wrong, but this usually happens when the nearest edge isn't clearly defined. On the whole, though, this tool is extremely effective at making selections.

Adjusting the Options

Before performing any edits with the Magnetic Lasso, you should familiarize yourself with the tool's advanced options, which can be found in the top options bar. Here are a few of the most important options:

  • Feather: This rounds the edges of your selection.
  • Anti-alias: This adds a subtle blur to the edges of your selection, so that they are less jagged. We recommend keeping this enabled.
  • Contrast: Before making a selection with the Magnetic Lasso, you can estimate the contrast between the two edges of your target, and then adjust the Contrast value accordingly. If the edges have a high contrast, you should increase this value, and vice versa. 
  • Frequency: This determines how often Photoshop adds anchor points as you draw your selection. 

Using the Magnetic Lasso

  1. First, you can find the Magnetic Lasso by clicking and holding your mouse over the Lasso tool. This will bring up a submenu, with the Magnetic Lasso at the bottom of the list. 
  2. Next, click anywhere on your image to start creating anchor points, and then start drawing around the edge. As you continue drawing, the Magnetic Lasso will add more anchor points, which can be adjusted later. We recommend zooming in as far as possible, so you get a better sense of where your selection should be. 
  3. At any point when making a selection, you can click to add anchor points manually, or undo the last anchor point by pressing Delete. When you've completed your selection, you can press Ctrl+Shift+I to invert the selection, and then press Delete to get rid of the background. Your Magnetic Lasso selection will be the only thing left on the canvas. 
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