1. Adobe Photoshop CS4 – Illustrated Unit B: Selecting Pixels

2. Adobe Photoshop CS4 - Illustrated
Objectives
Use the Marquee tools
Use the Lasso tools
Use the Magic Wand tool
Save and load selections
Adobe Photoshop CS4 - Illustrated

3. Adobe Photoshop CS4 - Illustrated
Objectives
Work with and save alpha channels
Understand anti-aliased edges
Work with a feathered edge
Refine selection edges
Adobe Photoshop CS4 - Illustrated

4. Using the Marquee Tools
In order to modify pixels they first need to be selected
The Marquee tools are the most basic tools available for making selections in Photoshop
The Rectangular Marquee tool is used for making rectangular or square selections
The Elliptical Marquee tool is used for making oval or circular selections
Pixels can be added to an existing selection and can be removed from a selection by using quick keys
Adobe Photoshop CS4 - Illustrated

5. Using the Marquee Tools
The black triangle on some tool icons indicates that there are additional hidden tools beneath the currently displayed tool
If not happy with a selection then it can be deselected and started over
Adobe Photoshop CS4 - Illustrated

6. Using the Marquee Tools
Positioning the first piece
Repositioning the circle piece
Adobe Photoshop CS4 - Illustrated

7. Adobe Photoshop CS4 - Illustrated
Using the Lasso Tools
There are three types of Lasso tools in Photoshop
Lasso, Polygonal, and Magnetic
Lasso tools are used for making free-form selections
click and drag anywhere on the canvas to create a section of pixels
it is usually easier to make small selections and use the Shift key to add them to create a more complex shape
the Polygonal Lasso tool functions like the Lasso Tool but with straight lines making it great for selecting shapes that are geometric
Adobe Photoshop CS4 - Illustrated

8. Using the Lasso Tools Selecting the interior of the object
Positioning the fifth piece
Adobe Photoshop CS4 - Illustrated

9. Using the Magic Wand Tool
The Magic Wand tool is very powerful
Click any pixel on the canvas and the Magic Wand tool selects other pixels based on tolerance-the similarity of their colors
the greater the tolerance value that is set for the tool, the more pixels it will select
click the Contiguous check box on the Options bar to specify that the Magic Wand tool selects only pixels that are contiguous (touch) the area
otherwise the Magic Wand tool will select similar pixels throughout the image
Adobe Photoshop CS4 - Illustrated

10. Using the Magic Wand Tool
As with any selection, once the pixels are selected that are needed they can be modified in many ways
Zooming in on areas of the image that are to be selected always helps when making selections including colors using the Hue/Saturation dialog box
Adobe Photoshop CS4 - Illustrated

11. Using the Magic Wand Tool
Selecting the white pixels
Selecting pixels without the Contiguous option
Results of changing the hue of selected pixels
Adobe Photoshop CS4 - Illustrated

12. Saving and Loading Selections
Making selections can be some of the most complex and time-consuming work when using Photoshop
It makes sense then to be able to save selections with the Photoshop file
Saving a selection is always a smart idea so that it can be easily accessed in the future
Adobe Photoshop CS4 - Illustrated

13. Saving and Loading Selections Saving Color Swatches
The Swatches panel can be used to change the foreground and background colors
click a swatch and the foreground color changes
click the Eyedropper tool and sample any pixel from the image which also changes the foreground color
To save colors that are created, simply float the pointer over a white area of the Swatches panel; when the pointer changes to a paint bucket icon click to add the color as a new swatch
Adobe Photoshop CS4 - Illustrated

14. Saving and Loading Selections
Save Selection dialog box
Pure Yellow Orange swatch on the Swatches panel
The finished project
Adobe Photoshop CS4 - Illustrated

15. Working with and Saving Alpha Channel
Alpha channels are simply saved selections
Alpha channels are listed on the Channels panel in Photoshop and are displayed as black and white thumbnail images
the selected areas are represented by white and the areas not selected by black
Alpha channels are not automatically saved when the file is saved; they need to be specified when saving a file
Adobe Photoshop CS4 - Illustrated

16. Working with and Saving Alpha Channel
Save Alpha Channels option in the Save As dialog box
The Dark Gray alpha channel
Adobe Photoshop CS4 - Illustrated

17. Understanding Anti-Aliased Edges
The outline of a selection is called the edge
The type of edge selected has a big impact on the work appears
the edge of a selection is always either aliased (hard edge which are very blunt and obvious) or
anti-aliased is a crisp but smooth edge
An anti-aliased edge in Photoshop creates a smooth transition between the edge and the background using many shades of edge pixel colors
Adobe Photoshop CS4 - Illustrated

18. Understanding Anti-Aliased Edges
Pixels are squares and a soft edge can not be made with squares; but the illusion can be created using anti-aliasing
Viewing the aliased edge
Viewing the anti-aliased edge
Adobe Photoshop CS4 - Illustrated

19. Working with a Feathered Edge
A feathered edge is a blended edge
Photoshop offers settings for controlling the length of the blend at the edge
The feather value is equal to the length of the feathered edge
when the feathered edge is applied to a selection, the edge is equally distributed inside and outside the selection edge
A vignette is a visual effect created with a feathered edge
the edge of the image, usually oval, gradually fades away
Adobe Photoshop CS4 - Illustrated

20. Working with a Feathered Edge
Drawing the feathered oval selection
The selected pixels relocated
Adobe Photoshop CS4 - Illustrated

21. Refining Selection Edges
The Refine Edge dialog box offers a number of useful options for viewing and refining the edge of a selection
Two key options in the dialog box are:
the Feather slider, used to dynamically feather a selection while previewing the result
the Contract/Expand slider, used to reduce of enlarge a selection
especially useful for removing halos from the edge of a selection
Useful keyboard commands for the Refine Edge dialog box (Win & Mac)
Adobe Photoshop CS4 - Illustrated

22. Refining Selection Edges
The Refine Edge dialog box
The silhouette of the eagle against black
Adobe Photoshop CS4 - Illustrated

23. Adobe Photoshop CS4 - Illustrated
Summary
The Marquee and Lasso tools provide different ways to select image pixels
The Magic Wand tool selects other pixels based on tolerance-the similarity of their colors
Saving selections makes it easy to access the selection in the future
After sampling a color of a selection, the color can be saved in the Swatches panel
Adobe Photoshop CS4 - Illustrated

24. Adobe Photoshop CS4 - Illustrated
Summary
Alpha channels are saved selections that need to be specified as an alpha channel to be saved when saving an image file
Images edges are made up of pixels that are square
a blunt square edge is an aliased edge
an anti-aliased edge is one that is made to look like a smooth edge
Edges can be feathered and refined
Adobe Photoshop CS4 - Illustrated