A Step-by-Step Guide to Mastering the Magnetic Lasso Tool in Photoshop

The magnetic lasso tool is one of the most useful selection tools in Photoshop for quickly selecting objects and people with complex edges. Once you get the hang of it, this clever tool can help you make accurate selections in a fraction of the time.

Follow this simple tutorial to truly master the magnetic lasso and start utilizing it for faster workflows

1. Locate and Select the Magnetic Lasso Tool

You’ll find the magnetic lasso tucked away in the toolbar with the rest of the selection tools. Click and hold on the standard lasso tool to expand the toolbar, then click the magnetic lasso icon to select it. The icon looks like a lasso with a magnet on it.

Once selected, the magnetic lasso will appear as your active tool in the toolbar

2. Adjust the Tool’s Settings and Preferences

Before starting your selection, you can modify a few settings to optimize the magnetic lasso for different scenarios

• Width: A higher value will sample from a wider area while drawing your selection line. Start low at around 10 pixels.

• Edge Contrast: A higher value detects edges with more contrast between foreground and background colors. Begin with a moderate value around 20%.

• Frequency: This controls how often fastening points are set. A lower frequency places more fastening points for a very accurate trace. Start with a moderate value around 100 pixels.

Tweak these preferences and experiment to see what settings work best for your specific image.

3. Click to Start Tracing Your Selection

Click once on your desired starting point on the edge you want to trace. This sets your first fastening point.

4. Trace the Edge While Hovering Over It

Now simply hover along the edge you want to select, without clicking. The magnetic lasso will automatically detect and follow the edge, setting fastening points along the way.

Go slowly and trace the full perimeter of the object or area you want to select. The selection line should automatically tweak and bend to follow the contours of the edge.

5. Set Additional Fastening Points as Needed

If the selection starts to stray from your desired edge, click manually to set down additional fastening points and get it back on track.

Fastening points anchor your selection, so add them anywhere the edge color or contrast changes abruptly or in highly detailed areas.

6. Complete the Selection by Clicking the Starting Point

Once you’ve traced the full perimeter, hover over your starting point until you see the circle icon indicating you can close the selection. Click once to complete it.

If needed, you can adjust the selection line afterward or delete points to refine it.

7. Improve Accuracy with Contrast and Edge Detection

If the magnetic lasso keeps jumping off the edge you want to trace, adjust the contrast and edge detection preferences.

Increase contrast to better differentiate the edge color from the surrounding areas. Reducing frequency and increasing width can also help it latch on better.

8. Use the Magnetic Lasso in Short Segments

On complex selections, trace short 3-5 inch segments rather than one continuous line. Click to set an anchor point anytime the tool starts to drift, then continue tracing from that new anchor point.

Segmenting helps ensure accuracy and allows the tool to reset and better detect edges.

9. Switch to the Standard Lasso When Necessary

If the magnetic lasso skips portions or won’t cooperate, quickly switch to the standard lasso tool (keyboard shortcut O) to manually fill in segments.

Use the magnetic lasso on high contrast stretches and the standard lasso on tricky areas. Toggling between the two makes for fast and accurate selections.

10. Refine Selections with Other Tools if Needed

If your selection still needs some fine-tuning, use tools like the Quick Selection tool or Magic Wand to improve it:

• Add to selection with the Quick Selection tool by brushing over missed areas
• Subtract from selection by holding Alt and brushing over extras
• Grow or contract the selection by 1-2 pixels using Select > Modify

Combining tools results in the best selections. The magnetic lasso gets you 90% of the way there, then refine with other tools to finish up!

Why Use the Magnetic Lasso Tool?

Once mastered, the magnetic lasso can save huge amounts of time when making complex selections. Here are some of the key benefits it provides:

• Speed: Traces edges incredibly quickly with just hover strokes

• Precision: Attracts right to details and maintains sharp edges

• Automatic: Reduces manual effort by detecting and following edges for you

• Segmentation: Allows dividing selections into short segments for improved accuracy

• Edge detection: Customizable edge contrast and sampling width to fit different images

• Organic shapes: Excels at selecting intricate, irregular shapes and objects

• Adjustable path: Selection line can be edited and perfected after the initial trace

The magnetic lasso is ideal for speeding up productivity and isolating subjects with intricate silhouettes. It works best on images with clearly defined edges and contrast between foreground and background.

Common Uses for the Magnetic Lasso Tool

Once you’ve mastered this tool, you’ll find countless uses for it in your editing projects. Here are just a few of the most common applications:

• Portrait cutouts: Quickly cut a portrait subject out from a background for compositing or effects

• Product shots: Select intricately shaped products like shoes or jewelry for cutouts and mockups

• Hair selections: Trace and cut out complex hair shapes with fine, wispy strands

• Nature photography: Select individual trees, leaves, or foliage from busy backgrounds

• Vehicles: Cut cars, planes or boats out cleanly from surrounding scenery

• Architectural photography: Select buildings with lots of curves and details from an urban setting

• Stylized portraits: Create graphic posters by selecting subjects with busy hair or clothing details

The magnetic lasso provides a huge productivity boost for any project requiring accurate selections. Use it to kickstart your complex selections before refining with other tools. With a little practice, you’ll be able to master selections faster than ever!