Sử dụng photoshop cs5 part 32 pot

Controls for the adjustment layer display on the Adjustments panel, and a new adjustment layer and layer mask appear on the Layers panel.B 6.. Adjustments panel, either click a button t

IN THIS CHAPTER Creating adjustment layers .197 Editing the settings for an

adjustment layer .199 Saving adjustment presets 200 Merging and deleting adjustment layers 201 Editing the adjustment layer mask 202 Using the Histogram panel 203

12

a photo, but it looks a bit dull or the

contrast is too strong? Or perhaps

the shadows or highlights lack detail?

Enter the digital darkroom Photoshop

offers a wide assortment of commands for

adjust-ing images, most of which are accessible from the

Adjustments panel In addition to letting you create

and edit 15 types of adjustment layers, this panel also

provides buttons for viewing, clipping, and restoring

your settings This chapter is devoted primarily to

the mechanics of using the Adjustments panel It also

includes an overview of the Histogram panel Specific

adjustment controls are covered in the next chapter

Creating adjustment layers

The effects of a command that is applied to a layer via

the Image > Adjustments submenu are permanent,

whereas the effects of an adjustment layer (applied via

the Adjustments panel) become permanent only when

you merge it downward into the underlying layer or

flatten your document We recommend using

adjust-ment layers whenever possible because they’re flexible,

meaning you can change the settings for them

when-ever you like — plus you can restack, hide, show, or

delete them, and even drag-copy them between files

Furthermore, adjustment layers don’t increase the file

size, so you can create and keep as many as you need

Note: The last six commands on the Image >

Adjustments submenu, including the valuable Shadows/

Highlights command, can be applied only via their

respective dialogs, not via an adjustment layer

For some of the kinds of adjustment layers that you

can create via the Adjustments panel, you can choose

a settings preset; for all of them, you can choose

indi-vidual settings (you can also modify the settings for

a preset) Via the presets, you can apply basic

adjust-ments quickly, such as to increase the image contrast

using three progressively stronger Levels presets, or

to increase the image saturation using progressively

stronger Hue/Saturation presets

To create an adjustment layer:

1 Click an image layer The adjustment layer is going

to appear above the layer you have selected

2 Optional: To restrict the adjustment effect to a

specific area of the image, create a selection

Continued on the following page

3 Display the Adjustments panel The Add an

Adjustment buttons and scroll list display A

4 Do either of the following:

Click the button for the desired adjustment type

They are arranged as follows: tonal adjustments

in the top row, color adjustments in the middle

row, and miscellaneous adjustments in the

bottom row

Click an expand/collapse arrow on the scroll

list to expand a category of presets, then click

a preset (not all of the adjustment types have

presets)

5 Controls for the adjustment layer display on the

Adjustments panel, and a new adjustment layer

and layer mask appear on the Layers panel.B

6 If you clicked a preset, the controls are already

set for you If you didn’t click a preset or you

want to alter the preset settings, choose the

desired settingsC (and A–B, next page)

➤ To redisplay the Add an Adjustment list when

the controls for an adjustment layer are

dis-playing, click the Return to Adjustment List

button at the bottom of the panel

➤ To enlarge the Adjustments panel, click the

Switch Panel to Expand View button at the

bottom of the panel Click the button again to

shrink the panel

➤ You can also create an adjustment layer by

choosing one of the same adjustment types from

the New Fill/Adjustment Layer menu at the

bottom of the Layers panel

Adjustments panel, either click a button to display controls for that adjustment type, or click

a preset, if available on the scroll list, to display its predefined settings.

we fine-tuned the Levels preset adjustment by dragging the midtones (gray) Input Levels slider slightly to the right.

To change the settings for an adjustment

layer:

1 On the Layers panel, double-click the thumbnail

(icon) for an adjustment layer The layer becomes

selected and the current settings display on the

Adjustments panel (Alternatively, you could

also click an adjustment layer, then show the

Adjustments panel, in two separate steps.)

2. Do either or both of the following:

Edit the settings

For a Levels, Curves, Exposure, Hue/Saturation,

Black & White, or Channel Mixer adjustment

type, choose a preset from the menu at the top

of the panel

➤ To undo the last individual slider, check box, or

other adjustment edit, press Ctrl-Z/Cmd-Z

➤ To lessen the overall impact of an adjustment

layer, lower its opacity via the Layers panel

➤ To expand or collapse the list of presets for all

the available adjustment types,

Alt-click/Option-click one of the expand/collapse arrows

➤ Each time you select and edit an existing

adjust-ment layer, those edits are listed collectively

on the History panel as one state (e.g., “Modify

Levels Layer”)

By holding down the View Previous State button, you can display the image temporarily without the new settings you have chosen for the currently selected adjustment layer

To view the image without the latest adjustment changes:

1 On the Layers panel, double-click an adjustment

layer thumbnail to select the layer and show the Adjustments panel, then edit the settings

2. To toggle the latest edits off, press and hold down

the View Previous State button or the \ key

To toggle the edits back on, release the button

or key

The Reset button on the Adjustments panel either undoes the most recent changes made (if any) to the current adjustment layer since the document was opened, or restores the default settings The button icon changes depending on whether the settings for the adjustment layer were edited Run through the following steps, just to see how the button works

To reset an adjustment layer:

1 Double-click an adjustment layer thumbnail to

display its settings on the Adjustments panel

2. Edit the settings

3 Click the Reset to Previous State button to

cancel the current changes and restore the last settings

4 Click the Reset to Adjustment Defaults

button (same button, different icon) to restore the default settings

Editing the settings for an adjustment layer

To hide the effect of an adjustment layer:

Click the visibility icon on the Adjustments

panel or Layers panel; click it again to redisplay

Normally, an adjustment layer affects all the layers

below it, but you can clip (restrict) its effect to just

the layer directly below it

To restrict the effect of an adjustment layer

to the layer directly below it:

1 On the Layers panel, click an adjustment layer A

2 On the Adjustments panel, click the Clip to

Layer button (Click it again to “unclip.”) B

Saving adjustment presets

Regardless of how you arrive at custom settings

(whether by choosing a preset first or not), you can

save those settings for future use

To save custom adjustment settings as a

preset:

1 Create and choose settings for an adjustment

layer Note that presets can be saved only for

Levels, Curves, Exposure, Hue/Saturation, Black

& White, Channel Mixer, and Selective Color

2 From the Adjustments panel menu, choose Save

[adjustment type] Preset In the Save dialog,

enter a name, keep the default location and

extension, then click Save Your user preset is

now available for any document via the Add an

Adjustment list on the Adjustments panel, and

also via the preset menu at the top of the panel

when the controls for that adjustment type (e.g.,

Levels or Curves) are displaying

➤ To delete a user preset, choose that preset,

choose Delete Current Preset from the panel

menu, then click Yes in the alert dialog

the overall contrast in this image.

the layer directly below it (the layer that contains the photo of olive oil).

Merging and deleting adjustment

layers

When you merge an adjustment layer downward, the

adjustments are applied permanently to the

under-lying image layer If you change your mind, either

choose Edit > Undo (right away!) or click the prior

state on the History panel

To merge an adjustment layer:

Do either of the following:

Click the adjustment layer to be merged

downward,Athen press Ctrl-E/Cmd-E.B

Right-click on or near the adjustment layer name

and choose Merge Down.

Note: Adjustment layers don’t contain pixels,

so you can’t merge them with one another

However, you can merge multiple adjustment

layers into an image layer (or layers) by using the

Merge Visible command (see page 145) or the

Flatten Image command (see page 146)

Adjustment layers are as easy to delete as they are

to create

To delete an adjustment layer:

Do either of the following:

Click the icon for an adjustment layer on the

Layers panel, then click the Delete Layer

button on the same panel or the Delete

Adjustment Layer button on the Adjustments

panel Click Yes if an alert appears Optional:

Click Don’t Show Again to prevent the alert from

reappearing

Click the icon or layer mask thumbnail for an

adjustment layer on the Layers panel, then press

Backspace/Delete (See also the sidebar at right.)

from the adjustment layer to the underlying image layer, which in this case is the Background.

BYPASSING THE AUTO-SELECT PARAMETER

The new Auto-Select Parameter option (on the Adjustments panel menu) causes the fi rst entry fi eld

on the panel to become highlighted automatically when you create an adjustment layer or when you double-click the icon for an existing adjustment layer on the Layers panel Although this option enables you to quickly enter or change values, it can be an annoyance because it prevents some shortcuts from working (e.g., selecting a tool via its letter shortcut or deleting a layer by pressing Backspace/Delete) If this option is on and you want to shift the focus from the Adjustments panel

to the Layers panel, click either the icon or the layer mask thumbnail for the adjustment layer

Editing the adjustment layer mask

By default, every adjustment layer has a blank white

layer mask To limit which area of the image the

adjustment affects, you can add black areas to the

mask, either by filling a selection or by applying

brush strokes, as we show you in the steps below

To edit the adjustment layer mask:

1 Click the mask thumbnail on an adjustment layer.

2 Press D to choose the default colors, then press

X to switch to black as the Foreground color

3. To partially mask the adjustment layer effect,

do either or both of the following:

Create a selection with any selection tool (e.g.,

Rectangular Marquee or Lasso), choose Edit >

Fill (Shift-Backspace/Shift-Delete), choose Use:

Foreground Color, click OK, then deselect.

Choose the Brush tool (B or Shift-B) On

the Options bar, choose a Soft Round brush,

Mode: Normal, and an Opacity of 100% (or a

lower opacity to create a partial mask), adjust

the brush diameter by pressing [ or ], then apply

brush strokes to the image.A–C

4 Optional: To reverse the effect of the mask in

specific areas, press X to switch colors (make the

Foreground color white), then with the Brush

tool, apply strokes to remove the mask

➤ To remove all black areas from the mask, deselect,

click the adjustment layer mask, choose Edit >

Fill, then choose Use: White in the dialog

➤ To confine the effect of an adjustment layer to

a small area, start with a fully black mask (click

Invert on the Masks panel or apply Edit > Fill,

Use: Black), then apply strokes with white

➤ To create a gradual mask by applying a gradient,

see pages 244–245 To refine the edge or density

of the mask, see pages 170–171

SHORTCUTS FOR LAYER MASKS

View the mask by itself in the docu-ment window

Alt/Option click the layer mask thumbnail (repeat to restore the normal view) View the mask

over the image as

a Quick Mask (the default color is red)

Alt-Shift/Option-Shift click the layer mask thumbnail (repeat to restore the normal view)

Deactivate or activate the mask

Shift-click the layer mask thumbnail (Layers panel)

or click the Disable/Enable button (Masks panel) Convert the

unmasked area into

a selection

Ctrl/Cmd click the layer mask thumbnail (Layers panel) or click the Load Selection from Mask button (Masks panel)

mask for that adjustment layer selected, we applied brush strokes to the top part of the image Now the adjustment is visible in only the bottom half of the photo.

strokes are rep-resented by black areas in the adjustment layer mask thumbnail.

Using the Histogram panel

The Histogram panel displays a graph of the

current tonal (light and dark) values in an image,

which updates dynamically as the document is

edited The panel is always accessible, even while the

Adjustments panel is being used or an adjustment

dialog is open You can better judge how adjustment

edits are affecting your document if you monitor the

changes in its histogram

After opening a photo into Photoshop — but

before you begin editing it — study the histogram to

evaluate the existing distribution of tonal values in

the image The horizontal axis on the graph

repre-sents the grayscale or color levels between 0 and 255,

the vertical bars represent the number of pixels at

specific color or tonal levels, and the contour of the

graph represents the overall tonal range

To choose a view for the Histogram panel:

From the Histogram panel menu, choose one

of the following: Compact View (just the

histogram),A Expanded View (the histogram

plus data and access to individual channels),Bor

All Channels View (all the features of Expanded

View, plus separate histograms for each channel)

To display document data in the latter two views,

check Show Statistics

For Expanded or All Channels view, choose an

option from the Channel menu: RGB, Ca specific

channel, Luminosity, or Colors To display

the individual channels in color, check Show

Channels in Color on the panel menu

While a large file is being edited, Photoshop

main-tains the redraw speed of the Histogram panel by

reading the data from the histogram cache — not

from the actual image When this is occurring, a

Cached Data Warning icon appears on the panel

Remember to keep updating the panel, as we instruct

you here (even while editing the settings for an

adjustment layer), so it will continue to reflect the

current tonal values of the image

To update the Histogram panel:

Do one of the following:

Double-click anywhere on the histogram

Click the Cached Data Warning icon.

Click the Uncached Refresh button

➤ To specify a Cache Levels value in the Preferences

dialog, see page 391

tonal values in the image are represented by black areas

on the graph.

Channel menu is set to Colors.