Photoshop
Selections
Marquee Tool
When you create a selection in an image, you will be able to modify the area that is inside the selection border without affecting other areas. Two examples of tasks you might perform after making a selection are cutting an area from an image or applying filter effects to an area of an image. Photoshop has different tools that offer this ability. One of these is the Marquee tool.
Like many of the tools in Photoshop, the Marquee tool is actually four tools in one. There is one button for it in the Toolbox but if you keep holding down the left mouse button while on the tool, a fly-out menu will appear with the other variations of the tool.
Practice Exercise: Marquee Tools and Options
Rectangular Marquee Tool
- We will use each tool on the Cat.psd image that we were working with previously. If you do not already have that image open, please open it now.
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If another tool is currently in use, you can switch to the Marquee tool by pressing M on the keyboard as an alternative to clicking on the tool itself.
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By clicking and dragging with the Marquee tool inside an image, you can select a rectangular area. If you hold down the Shift key while dragging, the selection shape will be constrained to a perfect square. With the cat image open, try drawing a rectangle around its head. As shown in this illustration, the marquee is an animated dashed line that surrounds the area you have selected. This is also referred to as the "marching ants". The cursor changes to this icon when a Marquee tool is being used: 
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You can remove the selection marquee by going to the menu Select > Deselect or by using the keyboard shortcut Ctrl-D (Cmd-D). The Deselect key command is one of many keyboard shortcuts in Photoshop. As you become more comfortable with the application, you will find that these shortcuts will save valuable time.
Rectangular Marquee Tool Options
Nearly every tool has options that you can set that affect how it will work. These are located in the Tool Options bar, located just below the menu bar. The following options are available for the Rectangular Marquee tool.
- Selection Options
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These four buttons allow you to:
- create a new selection,
- add to a selection,
- subtract from a selection, or
- intersect with another selection.
- Feathering
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Entering a value in this field will apply a "feather" to your selection. A feather will soften or blend the edges of a selection. The amount of feathering that will be applied will be determined by the number of pixels you enter in the text entry box. If you plan to apply feathering you must enter a value other than 0 in the text entry box before you make your selection.
The example at the right shows four different Feather settings. In each case the rectangular marquee tool was used and feathering was set to a different value before making the selection.
The first column shows the selections. As the feathering value increases, the corners of the rectangle appear more rounded. The second column shows what happened after the selections were filled with colour. This is where you can really see the effect feathering has. The selection was removed in the third column, leaving just the colour fill.
- Style
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The Style option will control how your selection is drawn by using the following commands.
- Normal
- Allows for a freehand, non-constrained selection to be drawn.
- Fixed Ratio
- With this option you will need to enter a ratio in the fields next to the pop-up menu. Any selection that you draw will conform to this ratio. For example, if you want to create a selection that is twice as wide as it is tall, enter 2 in the Width box and 1 in the Height box. As you click and drag in the image, the selection marquee will always be constrained to those proportions, regardless of its size.
- Fixed Size
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With this option, you define a fixed size for your selection; e.g., 50 pixels by 75 pixels. This can be helpful when working with specific sizes in web graphics. When this setting is used, you just have to click in the image and the selection will appear. No dragging is required.
The most efficient way to enter the width and height is to place your cursor in the Width box, delete any existing value, and type a number. You don't need to enter the unit of measurement (e.g., px) if that unit is already the default set in the Units & Rulers preferences. Press the Tab key to move over to the Height box, type a value there and press Enter (Return) to lock in the numbers. If you need to swap the Width and Height values, you can do so by clicking the icon between the two fields.
Displaying Selection Dimensions
The Info panel dynamically displays the dimensions of a selection made both during its creation and after it's been drawn. This is a very handy feature.
- To display the Info panel, go to Window > Info.
In the example shown here, the selection marquee is in the process of being drawn. The W (width) and H (height) fields continually update as the size of the marquee changes. Once you release the mouse button, these fields will display the dimensions of the completed marquee border. The X and Y fields display the current coordinates of the pointer in the image. The X value displays the distance from the left edge of the image document and the Y value shows the distance from the top of the document.
Elliptical Marquee Tool
This tool will allow you to draw an oval or circular marquee around a portion of an image. Holding down the Shift key while dragging with this tool will constrain the shape to a perfect circle.
- Try drawing a circular marquee around the cat's head.
Elliptical Marquee Tool Options
The Elliptical Marquee tool shares the same options as the rectangular Marquee tool (described above) but it has one additional option available.
- Anti-aliased
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When this check box is enabled the edge of the selection will be softened slightly to prevent a jagged edge from being formed. If you plan to apply anti-aliasing, you must enable the check box before you make your selection. In the image below, two selections were made of the cat's eye; one with anti-alias enabled and the other with it disabled (aliased). The image has been magnified by 500% so you can see the difference in the edges of the two selections. When anti-aliased, the edge of the selection contains partially transparent pixels through which the background colours will show. This creates a nice, smooth transition. There is a slight hint of transparent pixels in the aliased selection but not nearly to the same degree.
Single Row Marquee Tool
This tool will select a 1-pixel row of your image.
- Try selecting this tool and clicking once on the cat image. Notice that the selection will extend from the left edge to the right edge of the image.
Single Row Marquee Tool Options
This tool has the same Selection Options and Feather options described above under the Rectangular Marquee tool.
Single Column Marquee Tool
This tool will select a 1-pixel column of your image.
- Select this tool and click once on the cat image. Notice that the selection will extend from the top edge to the bottom edge of the image.
Single Column Marquee Tool Options
This tool has the same Selection Options and Feather options described above under the Rectangular Marquee tool.
- Leave your file open if you're moving onto the next lecture right away.
Marquee Tool Summary
- Selections are used to isolate part of an image before manipulating it in some way.
- The four Marquee selection tools are the Rectangular, Elliptical, Single Row and Single Column Marquee tools.
- When using the Rectangular or Elliptical Marquee tools, holding down the Shift key while dragging the tool will constrain the shape of the marquee to a perfect square or circle.
- Each Marquee tool has a number of options that affect how selections are drawn or applied to the image.
- The Selection Options allow you to create a new selection, add to a selection, subtract from a selection, or intersect with another selection.
- The Feather option will soften or blend the edges of a selection by the number of pixels you specify.
- The Style option will control how your selection is drawn and can be one of the following: Normal, Constrained Aspect Ratio, or Fixed Size.
- The Anti-aliasing option will soften the edges of a selection.
- The dimensions of a selection marquee created with the Marquee tool are displayed in the W and H fields in the Info panel.
- The Info panel dynamically displays the X and Y coordinates of the pointer location in the document window.
Marquee Tool Keyboard Shortcuts:
- Deselect: Ctrl-D (Cmd-D)
- Marquee tool: M
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