THE RIGHT TOOL FOR THE JOB
Photoshop CS4 Selection Tools
B.R. YOUNG
IT235 IMAGE EDITING & IMPLEMENTATION
Marquee Tool The primary tool for selecting areas for editing and adjustment, a marquee isolates the area from the rest of the image.
There are four types of marquee available
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Rectangular: Creates a rectangular selection. Elliptical: Creates round selection areas. Single Row: Draws a single horizontal line as a selection boundary. Single Column: Draws a single vertical line as a selection edge.
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The marquee subtools allow the user to modify the marquees edges
Holding the shift key while drawing an elliptical marquee will result in perfect circles. Hold the Alt key to expand the ellipse from the cursor center point.
Once selected, all filters, effects, and transformations will apply to the selection area only. Inverting the marquee will allow editing outside the original selection area.
A selection area can be sent to a new layer by pressing Ctrl + J, allowing the selection to be modified without altering the original image. Note the refined edge of the selection
Lasso Tool The lasso tools function much like a pen, allowing freehand selection of areas for modification. Although, these tools are only as precise as the users hand and mouse; accuracy can be increased by zooming in on the image, increasing mouse and screen resolution, and using a pen stylus.
There are three types of lasso tools available
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Lasso: Allows for a completely freehanded selection and is the least precise. Polygonal: Creates selection areas using straight lines and is slightly more precise. Magnetic: Makes selections based on color and shape similarities and is potentially the most precise.
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The polygonal lasso works well for selecting basic shapes with straight edges. It is possible to make curved selections, although it is sometimes tedious and often results in rough edges.
The magnetic lasso tool is more ideal for selecting complex areas, as the tool attempts to conform to an images lines based on color and shape similarities. Higher frequency of anchor points results in a smoother selection edge.
The magnetic lasso can be configured to follow similarities within certain distances of the pointer, level of sensitivity to edges, and frequency of anchor points.
Magic Wand The magic wand selects areas of similarly colored pixels, making it ideal for selecting large areas of relatively consistent color distribution. Depending on the color makeup of an image, the wand can be very accurate as it seeks out every pixel within its tolerance About Wand Tools
Although closely related, the magic wand and quick selection tool (discussed more in depth later in this presentation) have very different uses and methods of operation. Nevertheless, they work very well in conjunction and compliment each others functions.
The Magic Wand can be configured to modify the extent of its selection criteria
A lower tolerance restricts the selection to a smaller range of connected tones within the spectrum of the chosen color
A higher tolerance expands the selection to a wider range of connected tones within the spectrum of the chosen color
Deselecting the contiguous option allows the tool to extend its selection to the entire image regardless of connectivity
Quick Selection Tool
Much like painting with a brush, the quick selection tool expands towards defined edges of contrast with each stroke. Similar to the magic wand in its selection method, yet unhindered by the tolerances that restrain by color and shape similarities.
A Magic Paintbrush
The quick select tool can be fine tuned just like a brush, and constraints set much like the magic wand; truly a magic paintbrush!
The quick select tool has 3 main modes: Select, Add, and Subtract
Holding down the shift key while using the quick select tool will add to the selection area. This is very helpful in fine tuning selection edges, but more importantly, it allows the creation of selection areas outside of, or away from the original selection.
Holding down the alt key while using the quick select tool will subtract from the selection area. Once again, this is useful in refining selection edges, but really shines as one of the most efficient ways of removing areas within the original selection.
Selection Brush Method Selections can also be made and refined by using a combination of selection tools, masking, and standard brush strokes. This is beneficial to those who are more comfortable painting than tracing paths and marquees.
Start by using the lasso tool to draw a rough outline around the target. Dont worry, it does not have to be perfect.
Ensure that the default foreground and background colors are set to black/white, and press the quick mask button to toggle between mask and selection area modes.
Now the image is ready for refinement using the selection brush method. Its nothing but easy from this point forward.
Paint with black to add to the mask, which will later become the selection area. Paint with white to subtract from the mask or correct errors. The brush can be configured to accommodate the situation, even down to single pixels if required.
