Sử dụng photoshop cs5 part 36 potx

A Color Balance adjustment layer can be used to apply a warm or cool cast to an image or, con-versely, to neutralize an unwanted cast.. The three Tone choices of Shadows, Midtones, and H

A Color Balance adjustment layer can be used to

apply a warm or cool cast to an image or,

con-versely, to neutralize an unwanted cast The three

Tone choices of Shadows, Midtones, and Highlights

let you restrict the adjustments to a specific tonal

range, and each slider affects a pair of cool and

warm colors Note: If you need to pinpoint color

adjustments to an even narrower range, use Curves

or Hue/Saturation

To make an image cooler or warmer using

a Color Balance adjustment layer:

1 Click a layer or the Background A

2 On the Adjustments panel, click the Color

Balance button.

3 For Tone, click the range to be adjusted:

Shadows, Midtones, or High lights

Optional: Keep Preserve Lumi nosity checked

to preserve the tonal values of the layer as you

make corrections Or uncheck this option to

apply soft color adjustments to highlights, such

as to skin tones

4 Each slider pairs a cool color with a warm one

Move a slider toward any color you want to add more of or away from any color you want to reduce B–C (also A–B, next page) For exam-ple, you would move a slider toward green to subtract magenta, or toward yellow to reduce blue Watch how the overall image changes as you add or reduce a particular color

➤ To make the image warmer or cooler, move multiple sliders toward similar colors For example, to add a cool cast, you could move the first slider toward Cyan and the third one toward Blue Or to make an image warmer, move the first slider toward Red and the third one toward Yellow

5 Click any other Tone button, then adjust the

color sliders for that range You can click the visibility icon to compare the adjusted image with the original

A This image has a cool blue cast.

C The shadow areas look more neutral than before, but further corrections are needed.

See also the figures on the following page

BWe clicked the Shadows range for our Color Balance adjust-ment layer, then moved the sliders toward Red, Green, and Yellow to neutralize the shadows.

Applying a Color Balance adjustment

ATo neutralize the blue cast in the midtones,

we clicked Tone: Midtones, then moved the

sliders toward Red and Yellow A blue cast in

the highlights remains to be fixed.

BTo warm the highlights and neutralize the

remaining traces of the blue cast, we clicked

Tone: Highlights, then moved the sliders

toward Red and Yellow (and also slightly

toward Magenta) Now the food and the

plate look warmer (and more appetizing!)

and the shadows are more neutral.

For making precise hue and saturation corrections

without having to make a selection, try using a

Hue/Saturation adjustment layer With the Hue/

Saturation controls, you can target specific colors,

then shift just those colors to a different hue or

adjust their saturation or lightness This is a useful

way to swap out colors in a product or fashion shot

To use a Hue/Saturation adjustment layer

for color correction:

1 Click a layer A

2 On the Adjustments panel, click the Hue/

Saturation button.

3 Do any of the following:

To correct all the colors in the image, keep

Master as the choice on the second menu

Move the Hue slider to adjust all the hues, the

Saturation slider to adjust their color intensity,

or the Lightness slider to lighten or darken

them After adjusting the Lightness, you may need to increase the Saturation to revive any colors that became too light or dark

To change the hue of a specific color,Bclick

the Targeted Adjustment tool on the panel,

then Ctrl-drag/Cmd-drag horizontally over that color in the image.CThe color range you drag over is now listed on the menu, and the adjustment slider shifts to that color on the color bar Or to change the saturation of a spe-cific color, drag horizontally with the Targeted Adjustment tool over that color in the image without holding down Ctrl/Cmd

A We will change the blue napkin on the right side of this image to yellow, to coordinate better with the lemons on the left.

C Now the napkin is yellow.

B We created a Hue/Saturation adjustment

layer, then clicked the Targeted Adjustment tool

Holding down Ctrl/Cmd, we dragged over the

blue of the napkin until the hue shifted into the

yellow range Finally, we increased the Saturation

and reduced the Lightness for the adjusted colors.

Changes to the sliders are reflected

in the lower color bar

Applying a Hue/Saturation adjustment

Applying an Auto Color Correction

The Auto Color Correction Options dialog offers

a choice of three preset algorithms (formulas) for

adjusting the color and contrast in an image, and in

addition, it lets you correct the luminosity and color

temperature of the midtones

To apply an Auto Color Correction:

1 Open an image A

2 On the Adjustments panel, click the Levels

button, then hold down Alt/Option and click

Options (the Auto button becomes Options).

3. The Auto Color Correction Options dialog

opens.BMove it, if necessary, so it’s not blocking

the Levels histogram, which you should monitor

as you choose options

4 Click the Find Dark & Light Colors algorithm

(see the sidebar on the next page)

C We clicked the Midtones swatch to open this dialog, then chose a medium brown

to neutralize the color temperature of the sand.

B In the Auto Color Correction Options dialog, we clicked Find Dark & Light Colors and checked Snap Neutral Midtones.

A The midtones in the original image have a magenta cast, which

is noticeable in the sand.

5 Check Snap Neutral Midtones Any colors that

are close to neutral will be adjusted to match the Midtones target color swatch in the dialog

6 To adjust the color temperature of the image,

you can assign a subtle color tint to the

mid-tones Click the Midtones swatch The Select

Target Midtone Color picker opens.C Click the H button in the HSB group, then drag

the circle in the large square slightly to the right

(keep the S value around 10–30) Next, on the

vertical Hue bar, click a reddish-yellow hue to make the overall temperature of your image warmer, or a greenish-blue hue to cool it down

To adjust the brightness of the midtones, drag the circle slightly upward or downward (keep the

B value around 45–55)

Note: Midtones is the only swatch you need

to change; the other two swatches will be adjusted

automatically when the file is prepared for printing

7. Click OK to exit the Select Target Midtone Color

dialog, then again to exit the Auto Color Correction

Options dialog.A

When the alert dialog appears, offering you the

option to save the new target colors as defaults,

click No (we would rather choose settings on a

case-by-case basis than establish global default settings)

THE AUTO COLOR CORRECTION ALGORITHMS

and white Input Levels sliders inward to enhance

con-trast The sliders are moved the same amount for each

channel, to preserve color relationships (The Image >

Auto Contrast command also uses this algorithm.)

Levels sliders inward by a different amount for each

channel, and produces more noticeable color shifts and

changes in contrast than the other algorithms (The

Image > Auto Tone command also uses this algorithm.)

➤ Find Dark & Light Colors (our favorite algorithm)

positions the black and white Input Levels sliders in

each channel based on the average darkest and lightest

pixels in the image, and enhances the contrast (The

Image > Auto Color command also uses this algorithm.)

BBy comparison, clicking in the original image with the gray eyedropper in Levels (in the location shown above) failed to remove the magenta cast from the midtones.

AThe adjustments made

to the midtones via the Snap Neutral Midtones and Target Colors options in the Auto Color Correction Options dialog successfully removed the magenta cast.

➤ The Auto Color Correction Options dialog also opens when you Alt-click/Option-click the Auto button for a Curves adjustment layer

➤ You could also adjust the midtones by clicking a neutral gray area in the image with the gray point (middle) eyedropper in Levels or Curves, but this method is less reliable because it only works if you click in the right spot, which isn’t as easy as

it sounds.B