Adobe Photoshop CS5 – Illustrated
Unit B: Selecting Pixels
Objectives
Use the Marquee toolsUse the Lasso toolsUse the Magic Wand toolSave and load selections
Adobe Photoshop CS5 - Illustrated
Objectives
Work with and save alpha channelsUnderstand anti-aliased edgesWork with a feathered edgeRefine selection edges
Adobe Photoshop CS5 - Illustrated
Using the Marquee Tools
First select pixel to modifyMarquee tools Most basic tools for making selections Rectangular Marquee
• Rectangular or square selections Elliptical Marquee
• Oval or circular selections
Pixels Can be added or removed from a
selection using quick keysAdobe Photoshop CS5 - Illustrated
Using the Marquee Tools
Tool icon black triangle indicates additional hidden tools Located beneath currently displayed tool
If unhappy with selection Deselect selection Start over
Adobe Photoshop CS5 - Illustrated
Using the Marquee Tools
Positioning the first piece
Repositioning the circle piece
Adobe Photoshop CS5 - Illustrated
Using the Lasso Tools
Three types of Photoshop Lasso tools Lasso, Polygonal Lasso, Magnetic Lasso
Lasso tools: make free-form selections Click and drag anywhere on the canvas
to create section of pixels• Complex shapes: easier to make small
selections and add to them with Shift key
Polygonal Lasso tool Uses straight lines for geometric shapes
Adobe Photoshop CS5 - Illustrated
Using the Lasso Tools
Selecting the interior of the object
Positioning the fifth piece
Adobe Photoshop CS5 - Illustrated
Using the Magic Wand Tool
Magic Wand tool is powerfulClick any canvas pixel Tool selects other pixels based on
tolerance Greater the tolerance value, tool selects
more pixelsOptions bar contiguous check box Selects only contiguous (touch) pixels Or selects similar pixels throughout the
imageAdobe Photoshop CS5 - Illustrated
Using the Magic Wand Tool
Once needed pixels are selected Can modify in many ways
Zooming in on selected image areas Helpful when making selections,
including colors, using the Hue/Saturation dialog box
Adobe Photoshop CS5 - Illustrated
Using the Magic Wand ToolSelecting the white pixels
Selecting pixels without the Contiguous option
Results of changing the hue of selected pixels
Adobe Photoshop CS5 - Illustrated
Saving and Loading Selections
Making selections Complex and time-consuming work
Saving selections Smart idea Can easily access selection in the future
Adobe Photoshop CS5 - Illustrated
Saving and Loading Selections
Swatches panel Changes foreground/background colors
Click swatch and foreground color changes Click Eyedropper tool, sample any pixel
from the imageSaving created colors Float pointer over a white area of the
Swatches panel
Adobe Photoshop CS5 - Illustrated
Saving and Loading Selections
The finished project
Pure Yellow Orange swatch on the Swatches panel
Save Selection dialog box
Adobe Photoshop CS5 - Illustrated
Working with and Saving Alpha Channel
Alpha channels Saved selections Listed on Channels panel Displayed as black and white thumbnail
images Selected areas represented by white Areas not selected represented by black Not automatically saved when the file
saved Must specify when saving a file
Adobe Photoshop CS5 - Illustrated
Working with and Saving Alpha Channel
The Dark Gray alpha channel
Save Alpha Channels option in the Save As dialog box
Adobe Photoshop CS5 - Illustrated
Understanding Anti-Aliased Edges
Edge: outline of a selectionEdge types of a selection Aliased: hard edge
• Very blunt and obvious Anti-aliased: crisp but smooth edge
Anti-aliased edge Creates a smooth transition between
edge and background• Uses many shades of edge pixel colors
Adobe Photoshop CS5 - Illustrated
Understanding Anti-Aliased Edges
Pixels: squares and a soft edge Cannot be made with squares Illusion created using anti-aliasing
Adobe Photoshop CS5 - Illustrated
Viewing the anti-aliased edge
Viewing the aliased edge
Working with a Feathered Edge
Feathered edge: blended edge Settings available for controlling blend
length at the edge Feather value: equal to feathered edge
• Edge equally distributed inside and outside selection edge
Vignette: visual effect with feathered edge• Image edge: usually oval, gradually fades
away
Adobe Photoshop CS5 - Illustrated
Working with a Feathered Edge
Drawing the feathered oval selection
The selected pixels relocated
Adobe Photoshop CS5 - Illustrated
Refining Selection Edges
Refine Edge dialog box Offers useful options for viewing and
refining the edge of a selectionTwo key options in the dialog box Feather slider
• Dynamically feathers a selection while previewing the result
Contract/Expand slider reduces enlarged selection• Useful for removing halos from the edge of a
selectionAdobe Photoshop CS5 - Illustrated
Refining Selection Edges
Adobe Photoshop CS5 - Illustrated
Refining Selection Edges
The Refine Edge dialog box
Selection
The silhouette of the eagle against black
Adobe Photoshop CS5 - Illustrated
Summary
Marquee and Lasso tools Provide different ways to select image
pixelsMagic Wand tool Selects other pixels based on tolerance
Save selections Easy to access selection in the future
After sampling a selection color Color can be saved in the Swatches
panel Adobe Photoshop CS5 - Illustrated
Summary
Alpha channels Must specify saved selections as an
alpha channel when saving fileImages edges: made up of square pixels Blunt square edge: aliased edge Anti-aliased edge: made to look like a
smooth edgeEdges Feathered and refined
Adobe Photoshop CS5 - Illustrated