Selections are a great way to work on parts of your image independently, rather than manipulating the image as a whole.
Once you’ve selected a part of an image (e.g. a person’s head or other object), you can then manipulate this object separately from the rest of the image. This means you can cut the object out; add drop shadows; adjust the brightness/contrast; warp it; apply effects and filters easily – in fact, anything you like!
In this series of tutorials you’ll explore the various selection tools in Photoshop. On this page we start with the marquee and lasso tools.
The marquee tools
The simplest selection tools to use are the marquee tools. These include the Rectangular, Elliptical, Single Row and Single Column tools. Activate the tools by clicking and holding the mouse button on the top-left tool in the Tools palette:
Click on the tool you would like to use. The Rectangular Marquee tool lets you select a square or rectangular area; the Elliptical Marquee tool selects a circular or elliptical area; and the Single Row and Single Column tools select a single line of pixels either horizontally or vertically.
To use one of the marquee tools, click and drag out the selection with the mouse in your image:
By holding down the Shift key while dragging, you can constrain the selection to a square (for the Rectangular Marquee tool) or a circle (for the Elliptical Marquee tool):
Also, by holding down the Alt key while dragging, you can drag from the centre of the selection rather than from the edge – this is great for positioning circular selections precisely! Try it out to see what I mean.
The lasso tools
The lasso tools are great for seleting well-defined, irregularly-shaped areas. For example, they work well on strong foreground features of an image, such as a person’s head.
To use the Lasso selection tools, click and hold the mouse on the Lasso Tool icon in the Tools palette:
Click on the tool you’d like to use. The best way to learn about these tools is to try them out, but here are some pointers for you:
The regular Lasso tool lets you select freehand areas by clicking and dragging with the mouse – when you release the mouse the “loop” is closed, completing the selection. This tool is great for quickly selecting a rough area.
Polygonal Lasso tool
The Polygonal Lasso tool lets you create selections based on straight lines (or segments). This allows you more precise control when selecting using the mouse. Click with the mouse in your image to add the first fastening point, then move the mouse and click again to create a new fastening point with a segment in between. Continue in this way until you’re done, then close the selection border by moving the mouse over the first point and clicking (double-clicking with the mouse will also close the selection automatically). Try it!
Magnetic Lasso tool
The Magnetic Lasso tool is similar to the Polygonal tool, but it tries to add fastening points automatically based on the edge of the area you’re selecting. For this reason, the magnetic lasso tool works best when selecting areas that contrast well with their surroundings. As with the Polygonal tool, you click to start it off. You can also add your own points by clicking. Finish the selection by moving the mouse over the first point and clicking, or just double-clicking.
The Magnetic Lasso tool’s options let you control the tool’s sensitivity:
Width controls the range of pixels around the mouse pointer within which the tool looks for the edge of the object you’re tracing. If your object has well-defined edges you can set a high “Width” value and trace the object quickly and roughly. For more blurred edges, reduce the width and trace more precisely.
Edge Contrast specifies the tool’s sensitivity to the edge of the object you’re selecting. A high Edge Contrast value will only detect edges that contrast strongly with the rest of the image, whereas a lower value will detect softer edges.
The Frequency option controls how often the Magnetic Lasso tool will automatically place fastening points. A higher Frequency value will place more fastening points as you trace round the object.
- If you place a fastening point incorrectly with the Polygonal or Magnetic Lasso tools, press the Delete key on the keyboard to “undo” the point. You can keep pressing Delete all the way back to the first fastening point if necessary.
- As well as the automatic points added by the Magnetic Lasso, you can add your own manual fastening points by clicking with the mouse.
- You can temporarily turn the regular Lasso tool into the Polygonal Lasso tool by holding down Alt (Windows) or Option (Mac), then releasing the mouse button, then clicking where you want the end of the straight line segment to be. To revert to the regular Lasso, release the Alt/Option key while the mouse button is held down.
- Likewise, you can turn the Polygonal and Magnetic Lasso tools into the regular Lasso tool by holding down Alt/Option and dragging with the mouse.
- The Magnetic Lasso tool can be turned into the Polygonal Lasso tool by holding down Alt/Option and clicking with the mouse where you want the straight line segments to end.
- As well as double-clicking to close polygonal and magnetic selections, you can also hold down the Control key and click.
Now that you know how to use the marquee and lasso tools, take a look at some other Photoshop selection techniques: