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What
are Selection Tools?

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The
selection tools allow you to select a portion or a subset of an
image to work on. Most of Photoshops other tools and filters
can then be applied to this selected area, altering its color, shape,
texture, position and/or other attributes, while leaving the rest
of the image untouched.
Photoshop
contains three types of selection tools: the Marquee Tools, the
Lasso Tools, and the Magic Wand.
The
marquee tools are used to select a specific regularly shaped area.
The marquee tools include the Rectangular, Elliptical, Single Row
and Single Column Marquees:

The
lasso tools are used to select an irregular area. These tools include
the Lasso Tool, the Polygonal Lasso Tool and the Magnetic Lasso
Tool.

The
Magic Wand
is used to select areas of an image based upon color; the Magic
Wand does not have additional tools.
All
of the selection tools may be used individually or in conjunction
with each other to select exact areas of images. The Options Bar
allows you to choose to add to or subtract from a previous selection:

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If
you choose New Selection, any currently active selection will go away
when you make your new selection. If instead you would like to add
to the current selection, or subtract from it, make that choice in
the Options Bar. You can even choose to select an area formed by the
intersection of your selections.
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How
do I use
the Marquee Tools? |
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The
marquee tools let you select rectangles, ellipses, and 1-pixel-wide
rows and columns.
To
use the marquee tools:
1)
Select a marquee tool: Rectangular (for a rectangular selection),
Elliptical (for an elliptically shaped selection), Single Row (for
a one-pixel wide row) or Single Column (for a one-pixel wide column).
2)
Set the options you want in the Options Bar.
3)
Drag over the area you want to select. Hold down the Shift key if
you want to constrain the selection to a square or a circle.
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How
do I use
the Lasso Tools? |
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The
Lasso Tool and Polygonal Lasso Tool let you draw irregular selection
borders (both straight-edged and freehand):
- If
you want the selection to be completely or primarily freehand
(with a minimum of straight edges) then use the Lasso Tool.
- If
you want the selection to be completely or primarily straight
edges (with a miminum of freehand edges) then use the Polygonal
Lasso Tool.
With
the Magnetic Lasso Tool, you can draw the selection border, and
it will automatically snap to a high-contrast edge in the graphic.
To
use the Lasso Tool:
1)
Select the Lasso Tool from the Toolbox.
2)
Set any desired options in the Options Bar.
3)
To draw a freehand segment of the selection, simply drag the mouse.
4)
To draw a straight-edged segment of the selection, hold down the
Alt key and click at the desired beginning and end points of the
segment.
5)
To close the selection border, let go of the mouse button (without
holding down the Alt key).
To
use the Polygonal Lasso Tool:
1)
Select the Polygonal Lasso Tool from the Toolbox.
2)
Set any desired options in the Options Bar.
3)
To draw a straight-edged segment of the selection, click at the
desired beginning and end points of the segment.
4)
To draw a freehand segment of the selection, hold down the Alt key
and drag the mouse.
5)
To close the selection border, double-click the mouse button.
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Tip:
Think of the Lasso Tool and the Polygonal Lasso Tool as opposites
of each other. One (the Lasso Tool) usually does freehand selections,
but can be forced to make straight lines by holding down the
Alt key, while the other (the Polygonal Lasso Tool) does straight
line selections, but can be forced to do freehand by holding
down the Alt key. |
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To
use the Magnetic Lasso Tool:
1)
Select the Magnetic Lasso Tool from the Toolbox.
2)
Set any desired options in the Options Bar.
3)
Click to set the first endpoint of the selection.
4)
To draw a freehand segment, move the mouse pointer along the edge
you want to trace. (You dont have to hold down the mouse button,
although you can if you like.)
5)
As you move the pointer, the selection will automatically snap to
the strongest edge in the area around the pointer, based on the
Width set in the Options Bar. Periodically, intermediate points
are added to the selection border. While tracing the edge, click
to add a point if needed.
6) If
you want to switch to either the regular Lasso Tool or the Polygonal
Lasso Tool, hold down the Alt key. At that point, dragging the mouse
will let you draw freehand borders; clicking will let you draw straight
line segments.
7)
Close the selection border by double-clicking the mouse.
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How
do I use
the Magic Wand?
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The
Magic Wand Tool lets you select areas of an image based on similar
shades of color simply by clicking on the desired color.
To
use the Magic Wand Tool:
1)
Select the Magic Wand Tool from the Toolbox.
2)
Set the desired options in the Options Bar:
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Choose
whether to
- create a new selection,
- add to an existing selection,
- subtract from an existing selection, or
- intersect with the existing selection.
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Enter
a value from 0 to 255 in the Tolerance box. A low number
will let you select colors very similar to the pixel you click;
a high number will let you select a broader range of colors.
-
To select only adjacent areas using the same colors, select
Contiguous. Otherwise, all pixels using the same colors will
be selected.
- Check
or un-check the Contiguous option. If Contiguous
is not selected, all pixels
that are the same color as the selected pixel will be selected,
wherever they occur in the image. Otherwise, only adjacent pixels
of the same color will be selected.
3)
Click the color you want to select.
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An
example
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To
create the image at the bottom, we started with a photograph of
a bouquet of daffodils:
Original
Image
First we selected the yellow color ranges in the image, using the
Magic Wand:
Magic
Wand Selection
Next, we adjusted the selection to include just a single flower,
using the Lasso Tool and the add to and subtract
from selection options:
Adjusted
Selection
Once only the single daffodil remained selected, we copied that
selection and pasted it into a new file. We also created a green
background layer. The result:

Final
Image
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Copyright
© 2001, Bloomsburg University Virtual Training Help Center.
All rights reserved. This material may not be used without written
permission.
Contact Dr. Mary Nicholson at mjnich@bloomu.edu
The
screenshots contained in this tutorial were created in Adobe Photoshop
6.0.
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