- Web Design Tutorials, Tips, Top Resources

Using Photoshop Selection Tools

Part 3: Selecting with Photoshop's Lasso and Polygonal Lasso Tools - Creating a Triangle

by Shirley E. Kaiser, M.A., SKDesigns

Published 1999. Updated March, 2006. Copyright © 2001-2021, Shirley E. Kaiser, M.A., SKDesigns. All rights reserved. Published at with permission.

This Photoshop tutorial will help show you the basics of using the Lasso tool, one of Adobe Photoshop's helpful selecting tools. You'll find instructions for Photoshop CS2 and also for Photoshop 5.5.

Originally written when Photoshop 5.5 was new, updated March 2006 for Photoshop CS2 - so you'll find screenshots for both versions where Photoshop's interface differs between these versions.

What are the Lasso Tools and What Can they Do?

Photoshop's Lasso tools are designed for freehand selecting, and will create straight edge and freehand selection lines. Among its many uses, it is often used for carefully selecting certain elements of an image or creating certain shapes. To help learn how to work with the Lasso tools, below is a tutorial to create a triangle border selection using the Lasso tool (for 5.5) Photoshop Lasso Tool and the Polygonal Lasso tool (for CS2). Photoshop Polygonal Lasso Tool

Photoshop's Lasso Options (Lasso Options palette in 5.5) contains settings for feathering and anti-aliasing, as shown in Example 1.1a (CS2) and Example 1.1b (5.5) below. For the typical Web graphic, you'll probably use the Anti-aliased setting, especially for rounded or curved edges; however, turn off anti-aliasing (uncheck the box) if you need a crisp horizontal or vertical line selection.

Lasso tool Options Screenshot Ex. 1.1a: Lasso Tools Options
Photoshop CS2

example 1.2, Lasso tool on Toolbar   Example 1.1, Lasso options palette Ex. 1.1b: Lasso Tools, Lasso Tools Options Palette
Photoshop 5.5

For retouching, sometimes I will use the Lasso tool with a feathered edge using the Feather setting to copy a selection and then paste it as a new layer over a blemish, moving it around as needed. The feathering can provide a softer edge to provide a more seamless integration in a varied color graphic. The Rubber Stamp tool and the newer Healing Brush tool can also be used for this, too.

The Feather setting used depends on the application, of course. Feathering probably wouldn't be needed to cover a blemish on a solid color, for example. Experimenting with a variety of settings to see what it will do is a great way to get an understanding of this very helpful tool.


Tip 1: What to do when you make a mistake. Tips 4 and 5 below provide ways of altering what you've done. However, if you'd like to start over with your selection, from the drop-down menu, click on Select>Deselect. Then try again.

Tip 2: Zoom in or out. It can be quite helpful for accuracy to zoom in on your image while using the lasso tool to do selecting. From the drop-down menu select View>Zoom In or View>Zoom Out. Or with your keyboard, press CTRL+ (Zoom In) or CTRL- (Zoom Out).

Tip 3: Straight lines. For Photoshop CS2 using the Polygonal Lasso tool, click on the corner points only - don't drag. To complete the selection, click on the starting point to close the shape.

For Photoshop 5.5, hold down the ALT key in Windows (the Option key on a MAC), click the Lasso tool, then drag for each straight line segment, clicking where desired to change direction for the line.

Tip 4: Erasing segments. You can erase segments of the line by holding down the DEL (delete) key until the amount you wish is erased. It deletes fairly quickly, so watch out! <grin>

Tip 5: Adding and subtracting selections. Holding down the SHIFT key while you're selecting an area adds to the current selection. Holding down the ALT key (Options key for MACs) subtracts from the selection.

Tip 6: Patience. It will undoubtedly take some practice with the Lasso tools to gain the accuracy you'll need for certain selecting jobs. So be patient with yourself as you begin working with these helpful selecting tools.

top‘On this page’ menu

Straight-Edged Border Selection, aka Creating a Triangle Shape with the Lasso Tools

To demonstrate this, let's create a triangle shape using one of Photoshop's Lasso tools. We'll then either fill the inside of the triangle with the Paintbucket or with the Edit>Fill command, use Edit>Stroke for an outlined triangle, OR create a filled and outlined triangle, as you'll see below.

Important points:

OK, let's go.

  1. Click your mouse where you want to begin the triangle. I started at the top in Step 1 shown below.

    Step 2, Lasso tool, Partial Triangle
    Step 1 - Photoshop CS2

    Step 1, Lasso tool
    Step 1 - Photoshop 5.5

  2. For Photoshop CS2, then click on the next corner point - there's no need to drag the tool to the next corner.

    For Photoshop 5.5, then release and drag the tool to the next corner, clicking at the corner. Then release and drag the tool to the second corner, clicking the mouse again, as shown in Step 2 below. You might have noticed that the Lasso tool turned into the Polygonal Lasso tool.

    Step 2, Lasso tool, Partial Triangle
    Step 2

  3. For Photoshop CS2, then click on the next corner, which will be where you started, being certain to meet (thus adjoining) the line, clicking the mouse, as shown in Step 3 below.

    For Photoshop 5.5, then drag the tool to the next corner, which will be where you started, being certain to meet (thus adjoining) the line, clicking the mouse, as shown in Step 3 below.

    Step 3, Finishing the Triangle Selection
    Step 3

  4. Release the click. Now you should have a triangle selection, something like the example shown below. You may have also noticed that if the selection lines initially looked jagged as you did your selecting that Photoshop has straightened the selection lines from point to point.

    Step 4, the triangle is ready
    Step 4

  5. After choosing a foreground color to fill your triangle, you're now ready to:

    fill the inside of the triangle using Edit>Fill from the drop-down menu -OR- the Paintbucket tool,

    Step 5, ready to pour in the color with the Paintbucket  Step 6, Triangle completed Fill with Edit>Fill or
    Paintbucket tool

    -OR- create an outlined triangle using Edit>Stroke from the drop-down menu,

    ps_lasso_5outline  Outlined Triangle Outlined Triangle using Edit>Stroke

    -OR- both fill and outline.

    Triangle Filled and Outlined


    Filled, beveled triangleIf you wish to have an outlined and filled triangle, in the Stroke pop-up box, click the Location: Outside radio button. If you use Inside or Center, the line may not show up or appear inconsistent.

    See my tutorial, Creating Outlined Shapes with Photoshop's Marquee Tool for screenshots of the Stroke pop-up box and further instructions if needed.

  6. That's it! Now you're ready to save your image and use the triangle if you wish.
  7. Try creating more shapes and explore what this tool will do. Experimenting and playing around with these tools will go a long way with learning how to use them effectively.

top‘On this page’ menu

Related Resources

Related Resources at
Related Resources Elsewhere Adobe Photoshop Extended CS4

Adobe Photoshop Books, Video Training, Software
Recommended by

Read short reviews and find more book recommendations on Web site-related topics in our Recommended Books, Software section!

In association with In association with

top‘On this page’ menuNavigation belowSearch/Sidebar

Articles, Tutorials, Tips:

Most Popular Books

In association with  In Association with 

Our Other Sites


Effective, accessible, standards-based Web site design since 1996

SKDesigns -

Brainstorms & Raves

Weblog on Web design, CSS, standards, music, more. By Shirley Kaiser, SKDesigns.

Brainstorms & Raves

Within Articles, Tutorials, Tips:

Within Web Site Resources:
SkipShow or Hide Detailed Navigation