Learning Adobe Photoshop CS4 - Selection Tools

Learning Adobe Photoshop CS4By Greg Bowden

Guided Computer Tutorialswww.gct.com.au

Selecting Parts of Images

Chapter 2

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© Greg Bowden

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First published 2009

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Chapter

2Selecting Parts of Images

An important feature of any graphics program is its ability to select parts of images. This might include separating a image from its background or removing a background. In this chapter you will learn how to select parts of images using a variety of different tools.

Loading a Sample ImageA sample photo will be opened and some editing carried out on it.

1 Load Photoshop or close the current file.

2 Display the FILE menu and select OPEN.

3 Access the PScs4 SUPPORT FILES folder.

6 Press CTRL+0 or COMMAND+0 to set the size of the image window so that it fills the screen.

4 Open the CHAPTER 2 folder and select the CAT.JPG image

5 Select OPEN and the CAT.JPG image should load.

© Guided Computer Tutorials 20092-2

Learning Adobe Photoshop CS4

The Editing ToolsPhotoshop offers numerous ways of selecting parts of a drawing. Some of them are the basic, such as the EDIT MARQUEE TOOL and the LASSO TOOL, however, some are much more powerful, such as the QUICK SELECTION TOOL and the MAGIC WAND TOOL.

The Edit Marquee There are two main edit marquees, one is rectangular and the other is an oval.

A The Rectangular Marquee Tool

NOTE: A frame of ‘marching ants’ is added to the screen to highlight the selection. This selected area can be moved, copied, rotated, resized, transformed and adjusted.

1 Move the pointer over the EDIT MARQUEE TOOL (the top left tool) in the TOOLS panel, hold down the mouse button and the edit marquees should be displayed.

2 Select the RECTANGULAR MARQUEE TOOL.

3 Drag a frame around the cat’s head.



5 Press CTRL+Z or COMMAND+Z (or select UNDO MOVE from the EDIT menu) to return the selected area to its original position.

B The Elliptical Marquee Tool

NOTE: When you select the EDIT MARQUEE tool you can press SHIFT+M to toggle between the RECTANGULAR MARQUEE and the ELLIPTICAL MARQUEE.

4 Click on the MOVE TOOL (the top right tool in the TOOLS panel) and drag the selected area. Just the selection is moved.

1 Click and hold on the EDIT MARQUEE TOOL again and select the ELLIPTICAL MARQUEE tool.

2 Click outside the selection area to deselect it then drag a frame around the cat’s head. This time the selected area is an oval.



4 Press CTRL+Z or COMMAND+Z to undo the move.

NOTE: The SHIFT causes the ellipse to be a circle. If you hold down the SHIFT key and drag the RECTANGULAR MARQUEE TOOL, a square selection area is drawn.

Deselecting ObjectsWhen you select an area on the screen it remains selected until you select another area. To turn a selection off:

Press CTRL+D or COMMAND+D and the selection should be removed.

3 Select the MOVE TOOL again and move the selection. It is an oval.

5 Select the ELLIPTICAL MARQUEE TOOL again, click outside the selection, hold down the SHIFT key and drag a frame around the cat’s head. The area will be a circle.



The Lasso ToolsThe LASSO tools allow you to make more detailed area selections. There are three LASSO tools. The normal LASSO TOOL that you may have used in paint programs before, the POLYGON LASSO TOOL and the MAGNETIC LASSO TOOL.

A The Lasso Tool

The LASSO TOOL allows you to select freehand areas of an image.

1 Click and hold the mouse button on the LASSO TOOL in the TOOLS panel and the three LASSO TOOLS should be displayed. Select the LASSO TOOL.

2 Drag an area around the cat and, when you reach the starting point, release the mouse button.



4 Press CTRL+Z or COMMAND+Z to undo the move.

5 Deselect the area by pressing CTRL+D or COMMAND+D.

B The Polygon Lasso Tool

The POLYGON LASSO TOOL allows you to select sections of an image by dragging straight lines to form a polygon.

3 Select the MOVE TOOL and drag the selected area.

1 Click and hold the mouse button on the LASSO TOOL and select the POLYGON LASSO TOOL.



3 Click the mouse button to set the second polygon point and drag a line down to the base of the tale.

4 Click the mouse button to set the third polygon point and drag a diagonal line to below the cat’s right paw.

2 Move the cursor to the top left of the cat, click the mouse button to set the start point and drag a horizontal line to the right side of the cat.



6 Press CTRL+D or COMMAND+D to deselect the area.

NOTE: The MAGNETIC LASSO TOOL is one of the more difficult Photoshop tools and it will be covered when you are a little more experienced with Photoshop.

The Quick Selection ToolThere are a number of ways to accurately select an object within a photo. One of them is to use the QUICK SELECTION TOOL. Once you select the object you can place the selection on another background or on a white or transparent background. Let’s remove the cat from its current background and place it in another photo.

A Selecting the Cat

5 Click the mouse button and keep dragging lines until you get back to the starting point. A small circle is added to the pointer when you reach the starting point. Click the mouse button to complete the selection.

1 Click and hold the mouse button on the tool below the MOVE TOOL in the TOOLS panel and select the QUICK SELECTION TOOL.



3 Press CTRL+ or COMMAND+ a few times to zoom the screen so that the cat fills the screen.

NOTE: CTRL- or COMMAND- zooms the view out.

NOTE: The QUICK SELECTION TOOL is not perfect and it has trouble selecting areas where the colour of the cat is close to the colour of the background. For example, at the lower left side and between the tail and front legs.

2 Click on the arrow next to BRUSH in the OPTIONS BAR, set the brush DIAMETER to 20 and click again on the arrow to close the panel.

4 Click just above the left eye and the left side of the head then drag around the cat to select all of it.



B Adjusting the Selection

The program needs some help to get the selection of the cat more accurate. Areas of the background can be subtracted from the selection and areas of the cat not selected can be added to the selection.

1 Click on the SUBTRACT FROM SELECTION TOOL in the OPTIONS BAR.

3 Click on the ADD TO SELECTION TOOL in the OPTIONS BAR.

2 Click and drag around the area between the front paws and the tail to remove that area from the selection.

4 Click and drag around any parts of the cat that have been missed by the selection.

Documents

Learning Adobe Photoshop CS4 - Selection Tools