How To Use Photoshop's Lasso Tools

In Photoshop there are various ways to make a selection and also various reasons why you'd want to make a selection. You may want to remove something from its background, replace a sky or simply apply an edit to one part of a shot but not the other. Some of the selection tools are better suited for certain tasks than others are, however what tool you use can also be down to personal taste. In this series of tutorials we'll give a brief overview of all the selection tools on offer, showing you what they can be used for and how to adjust them.

This is part two of our series where we'll be looking at the Lasso tools. You can read part one here:
How To Use Photoshop's Marquee Selection Tools

Lasso Selection Tools

There are three types of Lasso tools (shortcut L) available to help you select part of an image. There's the Lasso tool and Polygonal Lasso tool which you can draw freehand with as well as create straight-edged selections. Then there's the Magnetic Lasso tool which is a handy tool to make selections with when you have a shape/object sat against a high contrast background. To change tools you can use your mouse or press Shift and L on your keyboard.

Lasso Tool Options

All three tools can be changed so you can make various selections, soften your selections and you can also apply Anti-aliasing to your selections too. All of this can be done in the tool bar towards the top of the window where you'll see a row of four shapes as well as the feather and anti-alias options.


By inputting a value into the Feather option you basically soften the edges of your selection so they aren't as straight and harsh. The edges are furthered softened by ticking the anti-aliased option. The four shapes allow you to tweak your selection to ensure everything you want selected is.

Looking left to right, the first option lets you create a New Selection. This means you can create a selection and if you don't like it you can simply click somewhere else on the image and start again. The second, Add To Selection, lets you expand / add the selection you've just created. To do this, just draw out more shapes next to or even over your original selection and the new adjustment will change the shape of it.  The third option, Subtract From Selection, lets you remove some of the selection and the final option, Intersect With Selection, will look at your original selection then at the new selection you've just made and only keep the selection where both adjustments overlap or intersect.

The Lasso Tool

To select an object with the Lasso tool just click your mouse near the object you want to select in your shot and drag the cursor around it until all of the object is selected, as you would when circling something with a pen on a piece of paper. When you return to your starting point your selection will turn into a line of 'running ants'. It's an easy tool to use as you simply drag your cursor around but it can be tricky trying to make a precise selection if you've not used it before. However, it does make it easy to select awkward shapes once you've had a bit of practice drawing free-hand. The various selection commands that were discussed above also mean you can go back and adjust your selection, adding and removing to/from it until you're happy.

The Polygonal Lasso Tool

Think of this tool like a cross between the Lasso tool and the Rectangular Marquee tool as you make straight-edged selections but you make each side of the selection individually so you can add as many straight lines to your selection as you'd like rather than having to stick with the four sided selection the Rectangular Marquee tool gives you.

It's not great for going around a palm leaf but can be used to make a selection from the sky in the shot. To begin your selection, click the cursor where you want it to begin and draw your shape out. Every time you click you'll get a new line you can change the direction of and you can do this as many times as you like until you complete your shape. To close the selection, just double-click and you'll see the line turn into 'running ants'. For small selections, use the zoom tool to magnify your image as it will make the selection process easier.

Magnetic Lasso Tool

What makes the Magnetic Lasso tool magnetic? Well when you make your selection, it will automatically look for the edge of the object you're selecting as you move around it. This is good news for most of us who don't have a very steady hand and tend to not make perfect selections when working free-hand.

To set your first anchor point, click your cursor where you want the selection to begin at the edge of your selection and continue to do this around the object you're selecting. You can click to add several anchor points or you can drag the mouse around your object and Photoshop will add its own anchor points. As you do, Photoshop will 'snap' the selection to the edge, helping you create a much more accurate selection with minimal effort. You can remove an anchor point by pressing the delete key and if you press the Caps Lock button on your keyboard you can also change your cursor to a circle with a crosshair in it which some of you may find easier to work with. To finish the selection, click the first anchor point you created to turn the selection in to a line of 'running ants'.

In the toolbar towards the top of the window you'll find various options you can change to make a tool that's designed more specifically for the shot you're working on.


You can control the area of the image Photoshop looks at to find the edge you're selecting by adjusting the tool's width. The more defined the edge is that you're working on the larger the width can be. If you begin making your selection and realise you want to change the width of your tool you won't be able to input a figure manually but you can press the left and right bracket keys on your keyboard to add / subtract from the figure.

Contrast tells Photoshop how much the background and the edge you are wanting to select contrast in brightness and colour. If they contrast well you can input a higher value, if they are quite similar, keep the value low.

Frequency lets you change the amount of anchor points Photoshop adds to the line but if you're adding your own points this isn't something you really need to worry about.

When using the Magnetic Lasso you'll probably find it easier to work on an image that's magnified so use the zoom tool to magnify the part of the shot you're selecting.