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Adobe Photoshop CS5 – Illustrated Unit B: Selecting Pixels

Adobe Photoshop CS5 – Illustrated Unit B: Selecting Pixels. Objectives. Use the Marquee tools Use the Lasso tools Use the Magic Wand tool Save and load selections. Objectives. Work with and save alpha channels Understand anti-aliased edges Work with a feathered edge

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Adobe Photoshop CS5 – Illustrated Unit B: Selecting Pixels

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  1. Adobe Photoshop CS5 – IllustratedUnit B: Selecting Pixels

  2. Objectives • Use the Marquee tools • Use the Lasso tools • Use the Magic Wand tool • Save and load selections Adobe Photoshop CS5 - Illustrated

  3. Objectives • Work with and save alpha channels • Understand anti-aliased edges • Work with a feathered edge • Refine selection edges Adobe Photoshop CS5 - 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 CS5 - 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 CS5 - Illustrated

  6. Using the Marquee Tools Positioning the first piece Repositioning the circle piece Adobe Photoshop CS5 - Illustrated

  7. CLASSROOM ACTIVITIES • True/False. The Elliptical Marquee tool is used for making oval or circular selections. (Answer: True) • What does the shift key do? (Answer: it adds to an existing selection, and it constrains a selection to a perfect shape) Adobe Photoshop CS5 - Illustrated

  8. 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 CS5 - Illustrated

  9. Using the Lasso Tools Selecting the interior of the object Positioning the fifth piece Adobe Photoshop CS5 - Illustrated

  10. CLASSROOM ACTIVITIES • What are the three types of Lasso tools? (Answer: Lasso, Polygonal, and Magnetic) • Which key do you press to add small selections of pixels? (Answer: Shift) Adobe Photoshop CS5 - Illustrated

  11. 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 CS5 - Illustrated

  12. 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 CS5 - Illustrated

  13. 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 CS5 - Illustrated

  14. CLASSROOM Activities • Discuss the difference between tolerance and contiguous. • What is the first step you should do before modifying the object? (Answer: Select it) Adobe Photoshop CS5 - Illustrated

  15. 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 CS5 - Illustrated

  16. Saving and Loading SelectionsSaving 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 CS5 - Illustrated

  17. Saving and Loading Selections Save Selection dialog box Pure Yellow Orange swatch on the Swatches panel The finished project Adobe Photoshop CS5 - Illustrated

  18. CLASSROOM ACTIVITIES • What does posterize mean in Photoshop? (Answer: Posterize is a special effect that is created by reducing the number of colors available for the image) • True/False. You can create and save selections and fill them with different colors. (Answer: True) Adobe Photoshop CS5 - Illustrated

  19. 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 CS5 - Illustrated

  20. Working with and Saving Alpha Channel Save Alpha Channels option in the Save As dialog box The Dark Gray alpha channel Adobe Photoshop CS5 - Illustrated

  21. CLASSROOM ACTIVITIES • Where can you find the Alpha channels? (Answer: They are listed in the Channels panel in Photoshop) • What should you do if you begin working and the wrong foreground or background is selected. How would you make the corrections? Adobe Photoshop CS5 - Illustrated

  22. 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 CS5 - Illustrated

  23. 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 CS5 - Illustrated

  24. CLASSROOM ACTIVITIES • True/False. A square has a soft edge. (Answer: False) • How much resolution do most monitors have? (Answer: 72 pixels per inch) Adobe Photoshop CS5 - Illustrated

  25. 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 CS5 - Illustrated

  26. Working with a Feathered Edge Drawing the feathered oval selection The selected pixels relocated Adobe Photoshop CS5 - Illustrated

  27. CLASSROOM ACTIVITIES • What is a feathered edge? (Answer: blended edge) • What is a vignette? (Answer: a visual effect in which an image gradually fades away) Adobe Photoshop CS5 - Illustrated

  28. 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 CS5 - Illustrated

  29. Refining Selection Edges Selection The Refine Edge dialog box The silhouette of the eagle against black Adobe Photoshop CS5 - Illustrated

  30. CLASSROOM ACTIVITIES • What are the two key options in the dialog box? (Answer: the Feather slider and the Contract/Expand slider) • 2. What key allows you to toggle the Preview option on and off? (Answer: [P]) Adobe Photoshop CS5 - Illustrated

  31. 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 CS5 - Illustrated

  32. 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 CS5 - Illustrated

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