Sử dụng photoshop cs5 part 24 doc

Using the Magic Wand tool With the Magic Wand tool, you simply click a color in the image and the tool selects all adjacent pixels of the same or a similar shade or color.. Like the Colo

Using the Magic Wand tool

With the Magic Wand tool, you simply click a color

in the image and the tool selects all adjacent pixels

of the same (or a similar) shade or color Like the

Color Range command, which is discussed on pages

156–157, the Magic Wand lets you control the range

of pixels the tool selects, but unlike Color Range, this

tool lets you add nonsimilar colors to the selection

To select color areas with the Magic Wand

tool:

1 Click a layer or the Background

2 Choose the Magic Wand tool (W or Shift-W)

3. On the Options bar:

Choose a Tolerance value (use the scrubby slider)

to control the range of colors the tool selects (for

a starting value, try between 30 and 40)

Check Anti-alias to allow the tool to add

semi-transparent pixels along the edges of the color

areas it detects This will produce smoother edge

transitions for your image edits

Check Contiguous to limit the selection to areas

that are connected to the first pixel you click, or

uncheck this option to allow the tool to select

similarly colored, noncontiguous (unconnected)

areas throughout the image with the same click

To select possible occurrences of a similar color

on all visible layers, check Sample All Layers, or

uncheck this option to select colors on just the

current layer

4 Click a color in the image.

5. Unless your image contains nothing but totally

flat color areas (which is unlikely), you’ll have to

do some extra work to refine the selection Do

any of the following:

To add to the selection, Shift-click any

unselected areas.A

To subtract any areas from the selection, hold

down Alt/Option and click them Or choose the

Quick Selection tool, then with the Alt/Option

key held down, drag short strokes across the

areas to be subtracted.B

To select additional, noncontiguous areas of

a similar color or shade based on the current

Tolerance value, right-click in the document and

choose Similar (This command works the same

whether the Contiguous option is checked or not.)

A To select the sky in this image layer, we clicked on the right side with the Magic Wand tool (Tolerance 38;

Contiguous checked), then Shift-clicked more sky areas to add them to the selection (as shown above).

B Some areas of the keys became selected, so we are using the Quick Selection tool with Alt/Option held down to remove them from the selection.

A Finally, we pressed Backspace/Delete to get rid of the selected pixels (in this document, the Background is hidden).

6 Optional: If you have selected a background

area that you want to remove and you clicked

a layer in step 1, press Backspace/Delete;Aor

if you clicked the Background in step 1, press

Ctrl-Backspace/Cmd-Delete.★ Deselect (Ctrl-D/

Cmd-D)

➤ You can change the Tolerance value for the

Magic Wand tool between clicks For example,

for more control when adding unselected shades

or colors along the edges of a selection, lower

the Tolerance value incrementally: Click with a

Tolerance of 30–40 first, lower the value to 15–20

and click again, then finally lower it to 5–10 and

click once more To select just one color or shade,

use a Tolerance of 0 or 1

➤ To undo the results of the last click made with

the Magic Wand tool or to undo the last use of

the Similar command, press Ctrl-Z/Cmd-Z

To expand a selection using a command:

With any selection tool chosen, choose Select >

Grow or Similar B–CThese commands use the

current Tolerance setting of the Magic Wand

tool You can repeat either command to further

expand the selection

➤ When the Magic Wand tool is selected, you can

access the Grow and Similar commands via the

context menu

TO ANTI-ALIAS OR NOT?

Before using a selection tool, check Anti-alias (if available) on the

Options bar to fade the edge of the selection to transparency, or

uncheck this option to produce a crisp, hard-edged selection.The effect

of anti-aliasing won’t be visible until you edit the selected pixels

The Anti-alias option was on

when this selection was created.

The Anti-alias option was off when this selection was created.

B We clicked the blue sky area with the Magic Wand tool (Tolerance of 35), Shift-clicked once

on the clouds…

C …then chose Select >

Similar The Tolerance setting controlled which pixel range was added to the selection.

Using the Color Range command

To create a selection with the Color Range command,

you click a color area in the document window or

in the preview area of the dialog, and depending on

the parameters you have chosen, all occurrences of

just one color or a range of related colors become

selected The dialog also provides controls for

widening or narrowing the range After closing the

dialog, you can further refine the selection with any

selection tool The more solid the color areas in an

image, the more effectively this command works

To create a selection using the Color Range

command:

1 Click a layer.The command will sample colors

from all the currently visible layers, but of course

only the current layer can be edited

2 Optional: Create a selection to limit where the

command can select colors

3 Choose Select > Color Range, or if a selection

tool is in hand, right-click in the document and

choose Color Range

4 In the Color Range dialog, choose from the

Select menu to limit the selection to Sampled

Colors (shades or colors you’ll click with the

Color Range eyedropper); to a specific preset

color range (e.g., Reds, Yellows); or to a

luminos-ity range (Highlights, Midtones, or Shadows)

5. If you chose Sampled Colors in the preceding

step, with the Eyedropper tool from the dialog,

click in either the dialog preview or the document

window to sample a color in the image.A–B

6 To add more colors or shades to the selection,

Shift-click in the document or preview window;

or to remove colors or shades from the selection,

Alt-click/Option-click

To expand or reduce the range of selected colors

and to control the number of partially selected

pixels, adjust the Fuzziness value C

7 Choose a Selection Preview option for viewing

the selection in the document window: None for

no preview, Grayscale to see a larger version of

the dialog preview, Black Matte to view the

selec-tion against a black background, or White Matte

to view the selection against a white background

Choose one of the latter two options when you

need to see if the edges are properly selected

B In the preview, the white areas represent fully selected pixels, the gray represent partially selected pixels, and the black areas represent unselected pixels.

A We chose the Color Range command, then with the Eyedropper, clicked the blue sky at the top of the image

C To fully select the sky and background, we Shift-clicked a lower section of the sky in the preview and increased the Fuzziness value to 105.

8 Click OK ANote: If you chose a preset color range and the image contains only minimal levels

of that color, an alert dialog will inform you that the selection marquee will be active but invisible

➤ Press Ctrl/Cmd to toggle between the Selection and Image previews in the dialog

A In the final Color Range selection, the entire blue sky and distant background are selected, including the noncontiguous areas between the columns.

USING THE LOCALIZED COLOR CLUSTERS OPTION IN THE COLOR RANGE DIALOG

The Localized Color Clusters option in the Color Range dialog creates a more accurate selection of colors based on their proximity to the sampled color Click

a layer, open the Color Range dialog, choose Select:

in the document window to sample a color.BCheck

Localized Color Clusters, then use the Range slider

to control the distance from the sampled color (or colors, if you Shift-clicked) within which similar colors may become selected.CYou can Shift-drag in the preview or document to add more color areas to the selection, within the current range,Dor Alt-drag/

Option-drag to remove color areas.E

C We checked Localized Color

Clusters and lowered the Range value

to 15 to shrink the selection area

D Next, we Shift-dragged to select more grapefruit colors, within the current Range.

E Finally, we dragged with Alt/

Option held down to remove some color areas from the selection.

B We chose the Color Range command, then with

the Eyedropper, clicked the grapefruit in the image

Hiding and showing selection edges

If your selection edges (those “marching ants”)

become distracting or annoying, you can hide them

from view If you do so, remember that the selection

remains in effect even when you can’t see it!

To hide or show the edges of a selection:

Press Ctrl-H/Cmd-H or choose View > Extras If

this command doesn’t work, make sure View >

Show > Selection Edges has a check mark A–B

Note: The Ctrl-H/Cmd-H shortcut hides or shows

all the options that are currently checked on the

Show submenu

➤ Mac OS users: The first time you press Cmd-H

after installing Photoshop and then opening

or creating your first document, an alert dialog

will appear.★ If you click Hide Photoshop,

the Cmd-H shortcut will be assigned to the

Photoshop > Hide Photoshop command; if you

click Hide Extras (as we do and recommend), the

shortcut will be assigned to the View > Extras

command The alert won’t reappear unless you

reset all warning dialogs (see page 386)

➤ If an option is unchecked in the View > Show >

Show Extras Options dialog, you can turn it on

or off only via the Show submenu, not by using

the Ctrl-H/Cmd-H shortcut For this reason, we

like to keep all the options checked in that dialog

➤ To verify that there is an active selection in your

document, click the Select menu If most of the

commands on the menu are available, you know

that there is an active selection

➤ You can hide or show selection edges via the

shortcut while using the Adjustments panel and

while any of the Image > Adjustments dialogs

are open

Swapping the selected and

unselected areas

To swap the selected and unselected areas:

Do either of the following:

With any tool chosen, press

Ctrl-Shift-I/Cmd-Shift-I (or choose Select > Inverse).C–D

With any selection tool chosen, right-click in

the document and choose Select Inverse.

(Repeat either step above to switch back to the

original selection.)

B …then we hid the selection edges

to gauge the results.

A We applied the Texture > Grain filter (Grain Type: Speckle)

to this selection…

C This is the original selection. D And this is the inverse

of the same selection.

Creating a frame-shaped selection

With the Rectangular Marquee or Elliptical Marquee

tool, you can create a selection in the shape of a

frame, either at the edge of the canvas area or

float-ing somewhere within it You can then apply filters

or adjustment settings to the frame-shaped

selec-tion or turn it into an adjustment layer mask (don’t

worry, you’ll learn those tricks later in this book)

Your edits will affect only pixels within the

frame-shaped border

To create a selection in the shape of a frame:

Method 1 (at the edge of the canvas area)

1 Click a layer.

2 Choose the Rectangular Marquee (M or

Shift-M)

3. In the document window, drag a marquee to

define the inner edge of the frame selection

4 Optional: To soften the edges of the selection,

click Refine Edge on the Options bar, choose On

White (W) from the View menu,★ zero out all

the sliders, adjust the Feather value to achieve

the desired degree of softness, then click OK

5 Right-click in the document and choose Select

Inverse A–B

Method 2 (within the image)

1 Click a layer.

2 Choose the Rectangular Marquee or Elliptical

Marquee tool (M or Shift-M), then drag to define

the outer edge of the selection

3 Alt-drag/Option-drag inside the first selection

to create the inner edge of the frame selection.C

Reposition the inner selection, if needed

C Alt-drag/Option-drag to create one rectangular

selection within another. B Finally, we added an editable type layer The type is

easy to read because we lightened the background.

A We created an inner selection with the Rectangular Marquee tool on this 300 ppi image, applied a Feather value of 25 px via Refine Edge, then chose Select > Inverse

Next, we used a Levels adjustment layer to lighten the area within the frame selection (see pages 206–207).