Introduction to the Lasso Tools in Photoshop

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Introduction to the Lasso Tools in Photoshop

This article is part of our series Photo Editing 101 by Ian Pullen. This series will cover all of the basics of using Photoshop for editing photos. If you’re just getting started with Photoshop or photo editing, or if you’re looking to improve your skills in this area, this series will provide an excellent foundation. If you want to make sure that you don’t miss future articles you can subscribe to our newsletter or follow us on Twitter, Google+, or Facebook. You can also find the articles that have already been published by visiting the Photo Editing 101 course page.

The Lasso tools in Photoshop allow you to make irregularly shaped selections. The Lasso tools comprise three different tools – the Lasso tool itself, the Polygonal Lasso tool and the Magnetic Lasso tool.

The first two tools allow you to specify your own selections, either with hand drawn or straight edges. The Magnetic Lasso tool introduces some more advanced features that allow you to make selections that follow edges, with Photoshop doing most of the heavy lifting for you. Please read on and I’ll introduce you to the different Lasso tools and show you how to use them in your own work.

How Do You Activate the Lasso Tools?

Introduction to the Lasso Tools in Photoshop

The Lasso tools are represented by the third icon in the Tools palette and if you click and hold on the icon, a small fly out menu appears that allows you to select from the three different Lasso tools.

To use the Lasso tool, you just click and drag your mouse. When you release the mouse button, the selection will be closed automatically. The Polygonal Lasso tool requires you to click at different points, which are then joined by a straight selection. You can close the selection by double-clicking or moving the cursor back to the start point and clicking. We’ll look at the Magnetic Lasso later.

What are the Different Selection Modes?

Introduction to the Lasso Tools in Photoshop

All three of the Lasso tools share some features, which you’ll find in the tool options bar near the top of the working interface. The Magnetic Lasso has some additional options which we’ll look at later.

The Selection Modes are not only shared by the Lasso tools, but all of the selection tools in Photoshop and these are represented by the four icons to the left of the tool options bar. The modes are as follows:

  • New selection – this is the default setting and, when activated, whenever you start to draw a selection, any existing selections will be deactivated.
  • Add to selection – this can be used to draw multiple selections, which can be separate or combined.
  • Subtract from selection – when this is used, the area where the new selection intersects with any existing selections is deselected.
  • Intersect with selection – this works in the opposite way to Subtract from selection, so that only the areas where the new selection intersects with existing selections remains selected.

If that isn’t entirely clear, have a go with the different modes and you’ll soon understand their differences.

What Does the Feather Option Do?

Introduction to the Lasso Tools in Photoshop

Before you start making a selection with any of the Lasso tools, you can add a value to the Feather input field to soften the edge of your selection. You can add a value between 0 and 250. The higher the value, the softer the feathered edge will be. In the screen shot, you can see that I made two selections and filled each with black. The upper black shape had the selection feather set to 0px, while the bottom one was set to 250px. The effect is quite apparent. You can also feather a selection after it has been created by clicking the Refine Edge button and using the Feather slider – you’ll find additional controls there too.

The Anti-alias checkbox also softens the edge of your selection, but at the pixel level, so that selections do not have hard jagged edges. If you fill a selection and then zoom in on the edge, you will be able to see the differences.

How Does the Magnetic Lasso Tool Work?

Introduction to the Lasso Tools in Photoshop

I’ve already mentioned that the Magnetic Lasso tool has additional options and these allow you some control over how the tool works. It detects differences in contrast to find edges in your photos. You just click once on an edge point of the area that you want to select and then drag the cursor along the edge. As you do so, you will see a selection line is automatically created, with occasional anchor points being added to the line. You can close the selection by double-clicking or returning the cursor to the start point and clicking. You can also click as you drag to add anchor points manually, which can help in areas where the contrast is lower.

If you don’t have precise cursors set in your Photoshop preferences, pressing the Caps lock button on your keyboard will switch the cursor icon to a circle with cross hair, which makes the tool easier to use.

With the precise cursor visible, adjusting the Width setting will change the size of the cursor circle. The larger it is, the greater the area it will look for contrast differences that suggest edges. It’s best to have this on the smaller side and zoom in as necessary.

The Contrast setting adjusts the sensitivity of the Magnetic Lasso. In images where there is strong contrast differences between the subject and background, you can set this higher. When contrast is low, you will need this setting to be lower.

The Frequency setting adjusts how often anchor points are added as you draw your selection. The higher the value, the more often anchor points will be added. This may lead to a more accurate selection, but remember that you can always manually add anchors as you draw.

If you find an anchor point is placed badly, you can press the Delete key and the last anchor point added will be deleted. You can keep pressing the Delete key to remove further anchor points.

Introduction to the Lasso Tools in Photoshop

This final screen shot shows a Hue-Saturation Adjustment Layer applied to the selection.


The three different Lasso tools make it quite easy to quickly create selections. The Magnetic Lasso tool is particularly useful, allowing you make more complex edge based selections surprisingly quickly.

See more articles in the Photo Editing 101 series.