Photoshop Selection Tools: Marquee, Lasso, and Magnetic Lasso, Lecture notes of Computer science

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EDUCATIONAL SYSTEMS

TECHNOLOGICAL INSTITUTE

Murallon, Boac, Marinduque

COMPUTER 8 Quarter 1 - Module 6 Selection Tool Lesso Selection Tool

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6.1 Selecting Pixel 6.2 Marquee Tools 6.3 Lasso Tools 6.4 Polygonal Lasso Tool 6.5 Magnetic Lasso Tool 6.6 Quick Selection Tool 6.7 The Magic Wand 6.8 Refine Edge Option

KEY TERMS:

 Marquee

 Magnetic Lasso

 Lasso

 Shape Tool

 Magic Wand

 Contrast

 Radius

GENERAL OBJECTIVES

At the end of the lesson, we should be able to:

1. Familiarize yourself with the different Photoshop tools that can enhance your images like the filter gallery, layer style, pen tool and type tool;
2. Practice selecting pixels using the selection tools;
3. Use the move tool to manipulate edited images and apply effects;
4. Recognize different photo editing softwares and its features;
5. Develop a creative skill in using the filter gallery;
6. Apply artistic texture, sketch, brush stroke, and stylize effect to your image to reinvent your document;
7. Use the different layer style that can be applied to your document;
8. Draw a line segment, curve, and that freeform object using the pen tool;
9. Add text effects to your image to produce a creative artwork.

SELECTING PIXELS

 Hold down Shift key as you drag to constrain the marquee to a square or circle (release the mouse button before you release Shift to keep the selection shape constrained).  To drag a marquee from its center, hold down Alt key after you begin dragging.  With the Single Row or Single Column Marquee tool, click near the area you want to select, and then drag the marquee to the exact location. If no marquee is visible, increase the magnification of your image view. QUICK TIPS To reposition a rectangle or elliptical marquee, do the following:  Press the mouse button and drag it to create a selection border.  Hold down the spacebar and continue to drag.  If you need to continue adjusting the selection, release the spacebar but keep the mouse button depressed.

LASSO TOOLS

There are three types of Lasso tools in Photoshop: Lasso, Polygonal Lasso, and Magnetic Lasso. Lasso tools are also used for making free-form selections. LASSO TOOLS The Lasso tool is useful for drawing free-form segments of a selection border.

Try This!

1. Open an image from the school picture collection you shot.
2. Select the Lasso tool , and set feathering and anti-aliasing in the options bar.
3. To add to, subtract from, or intersect with an existing selection, click the corresponding button in the options bar.
4. Do either of the following:  Drag to draw a freehand and selection border.  Switch between freehand and straight-edged segments. Press Alt and click where segments should begin and end.
5. To close he selection border, release the mouse without holding down Alt. QUICK TIPS  To erase recently drawn straight segments, hold down the Delete key.  Click Refine Edge to further adjust the selection boundary.  Press Alt key to switch between segments.

POLYGONAL LASSO TOOL

The Polygonal Lasso tool is useful for drawing straight-edged segments of a selection border.

Try This!

1. Open an image from the school picture collection you shot.
2. Select the Polygonal Lasso tool and select options.
3. Specify one of the selection options in the options bar.
4. Set feathering and anti-aliasing in the options bar. See Softer the Edges of the selections.
5. Click in the image to set the starting point.
6. Do one or more of the following:  To draw a straight segment, position the pointer where you want the first straight segment to end, and click. Continue clicking to set endpoints for subsequent segments.  To draw a straight line at a multiple of 45°, hold down Shift as you move to click the next segment.  To draw a freehand segment, hold down Alt and drag. When you are finished, release Alt and the mouse button.  To erase recently drawn straight segments, press the Delete key.
7. Close the selection border.  Position the Polygonal Lasso tool pointer over the starting point (a closed circle appears next to the pointer), and click.
8. If the pointer is not over the starting point, double-click the Polygonal Lasso tool pointer, or Ctrl-click.
9. Click Refine Edge to further adjust the selection boundary. MAGNETIC LASSO TOOL When you use the Magnetic Lasso tool, the border snaps to the edges of defined areas in the images. The Magnetic Lasso tool is not available for 32-bits-per-channel images. The Magnetic Lasso tool is especially useful for quickly selecting objects with complex edges set against high-contrast backgrounds.

Try This!

1. Open an image form the school picture collection you shot.
2. Select the Magnetic Lasso tool.
3. Specify one of the selection options in the options bar.
4. Set feathering and anti-aliasing in the options bar. See Soften the Edges of selections.

Try This!

1. Open an image from the school picture collection you shot.
2. Select the Quick Selection tool.
3. In the options bar, click one of the selection options: New, Add To, or Subtract From. New is the default option if nothing is selected. After making the initial selection, the option changes automatically to Add to.
4. To change the brush tip size, click the Brush pop-up menu in the options bar, and type in a pixel size or drag the slider.
5. Use the Size pop-up menu options to make the brush tip size sensitive to pen pressure or a stylus wheel.
6. Choose Quick Selection options.
7. Paint inside the part of the image you want to select. The selection grows as you paint. If updating is slow, continue to drag to allow time to complete work on the selection. As you paint near the edges of a shape, the selection area extends to follow the contours of the shape edge.  To subtract from a selection, click the Subtract from option in the options bar, then drag over the existing selection.  To temporarily switch between add and subtract modes, hold down the Alt key.
8. Click Refine Edge to further adjust the selection boundary. THE MAGIC WAND This tool allows you to select an area of an image based on its color. The tool is located near the top of the Photoshop Toolbox. When you click an area in an image with the magic wand, all areas which have a similar color are selected. QUICK TIPS  You can specify various options to determine the exact selection.  You cannot use the Magic Wand tool on an image in Bitmap mode or on 32-bits-per- channel images.  Sample All Layers. Creates a selection based on all layers.  Auto-Enhance. Reduces roughness. It also removes blocks in the selection boundary. Auto-Enhance automatically flows the selection towards image edges and applies some of the edge refinement you can apply manually in the Refine Edge dialog with the Contrast and Radius options.

Try This!

1. Open an image from the school picture collection you shot.
2. Select the Magic Wand tool.
3. Specify one the selection options in the options bar. The Magic Wand tool’s pointer changes depending on which option is selected.
4. In the options bar, specify any of the following:
5. In the image, click the color you want to select. If Contiguous is selected, all adjacent pixels within the tolerance range are selected. All pixels in the tolerance range are selected.
6. Click Refine Edge to further adjust the selection boundary or view the selection against different backgrounds or as a mask. THE MAGIC WAND It improves the quality of selection edges, letting you extract objects with ease. This tool makes it easier to select certain objects and make them look more realistic when imposed on a new background.

Try This!

1. Open an image from the school picture collection you shot.
2. Create a selection with any selection tool.
3. Click Refine Edge in the options bar; or choose Select > Refine Edge.  View Mode. From the pop-up menu, choose a mode to change how the selection is displayed. For information about each mode, move the pointer over it until a tool tip appears.  Show original displays the original selection for comparison.  Show Radius displays the selection border where edge refinement occurs.  Refine Radius and Erase Refinements tools. This tool allows you to adjust the border area in which edge refinement occurs.  Tolerance. Determines the color range of selected pixels. Enter a value in pixels, ranging from 0 to 255. A low value selects the few colors very similar to the pixel you click. A higher value selects a broader range of colors.  Anti-aliased. Creates a smoother-edged selection.  Contiguous. Selects only adjacent areas using the same colors. Otherwise, all pixels in the entire image using the same colors are selected.  Sample All Layers. Selects colors using data from all the visible layers.