Sử dụng photoshop cs5 part 12 ppt

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72 Chapter 4






To apply tonal adjustments using the
Parametric sliders in the Tone Curve tab:
1. Click the Tone Curve tab, then the nested
Parametric tab.
A–B
Behind the curve you’ll
see a static display of the current histogram.
2.
Increase the Highlights, Lights (upper mid-
tones), Darks (lower midtones), or Shadows
value to lighten that tonal range and thereby
raise the corresponding portion of the curve
above the diagonal line,
C
or reduce the value
to darken that tonal range and thereby lower
that portion of the curve below the straight
diagonal line) (
A–B
, next page). If you need
to intensify the contrast, try moving the
Highlights and Lights sliders in opposite
directions.

3.
After adjusting the sliders, you can move the
region control (located below the graph) to
expand or contract the range of tonal values
that each slider adjustment aects. e left
region control aects the Shadows slider, the
right region control aects the Highlights
slider (
C–D
, next page), and the middle region
control aects the Lights and Darks sliders. e
more a control moves the curve away from the
straight diagonal line, the more adjacent tonal
ranges are aected; the more a control moves
the curve closer to the diagonal line, the fewer
adjacent tonal ranges are aected.
➤ Except for the Recovery slider, the sliders in the
Basic and Tone Curve tabs shouldn’t be pushed
to the extreme left or right.
Using the Tone Curve tab
After making adjustments in the Basic tab, the next
step is to improve the contrast in the photo. Using
the Parametric sliders in the Tone Curve tab, you
can adjust the highlights, lights, darks, and shad-
ows separately. Although you could also adjust the
curve manually (employing the same techniques
as for a Curves adjustment layer in Photoshop), if
you don’t click and drag the curve in just the right
way, the image could become posterized. For this
reason, we encourage you to use the sliders instead.

If you use Adobe Photoshop Lightroom, the
Parametric curve and sliders here will look familiar.

C
 e L i g h t s a d j u s t m e n t d a r k e n e d t h e u p p e r m i d t o n e s ,
and the Darks adjustment darkened the lower midtones.
A
In this photo, the
highlights lack detail
and the midtones
lack contrast.

B
In the Parametric
tab (Tone Curve tab),
we reduced the Lights
and Darks values,
which had the eect
of lowering the mid-
section of the curve.
Region controls

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Camera Raw 73


D
 e a d j u s t m e n t t o t h e r e g i o n c o n t r o l e x p a n d e d t h e d a r k e n i n g e  e c t o f t h e
Lights and Darks sliders, which further darkened both the light and dark tonal
ranges. In this nal image, the exposure looks just right.

C
We moved the middle region control to
the right (to 68), which had the eect of
lowering the midsection of the curve.

A
To darken the highlights, we reduced
the Highlights value. is had the eect
of lowering the top of the curve.

B
To reduce the highlights, instead of moving a Tone Curve slider, we clicked
the Targeted Adjustment tool, then dragged downward over a highlight area.
 i s l o w e r e d t h e H i g h l i g h t s v a l u e ( p u s h e d s o m e h i g h l i g h t a r e a s i n t o t h e u p p e r
midtone range) and recovered details, most noticeably in the clouds. Overall, the
image contrast is improved.

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74 Chapter 4
Using the HSL/Grayscale tab



In the HSL/Grayscale tab, you can adjust the hue,
saturation, or luminance of individual colors. e
sliders in this tab are powerful! (ey can be used
as sliders or scrubby sliders.)
To adjust individual colors via HSL sliders:
1. Click the HSL/Grayscale tab, and double-

click the Hand tool to t the image in the
preview.
A
2. Click the nested Hue tab. Move any slider to
shift that color toward its adjacent hues, as
shown in the bar. For example, you could shift
the Greens toward yellow to make a photo
warmer, or toward aqua to make it cooler.
3.
Click the Saturation tab (
A–B
, next page).
Move any slider to the left to desaturate a
color (make it grayer) or to the right to make it
more vivid (more pure). Avoid oversaturation,
to keep the photo from looking unnatural and
from becoming unprintable.
➤ To make a sky look more vivid, increase the
saturation of the Blues and Aquas; or to
make a sunset warmer, increase the satura-
tion of the Yellows or Greens; or to make
the lighting look gray and hazy, lessen the
saturation of the Yellows or Greens.
4.
Click the Luminance tab (
C–D
, next page).
Move a slider to the left to make that color
darker (by adding black) or to the right to make
it lighter (by adding white). Avoid overlightening

the colors, to prevent clipping of the highlights.

A
In the original photo, the sky lacks contrast and the greens and yellows
in the eld are oversaturated.
USING THE TARGETED ADJUSTMENT TOOL
With the Targeted Adjustment tool in Camera Raw,
you can apply local adjustments to a photo. After
choosing the tool, click a nested HSL tab or click
and hold on the tool and choose Hue, Saturation, or
Luminance from the menu. Next, drag over a specifi c
color area to apply a correction: Drag upward or to
the right to increase the slider values, or downward
or to the left to decrease those values. The sliders
corresponding to the color under the pointer will
shift automatically.

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Camera Raw 75
A
In the nested Saturation tab of the HSL/
Grayscale tab, we reduced the saturation of the
Oranges and increased the saturation of the Blues.


B
 e S a t u r a t i o n a d j u s t m e n t s l e s s e n e d t h e i n t e n s i t y o f t h e o r a n g e s i n
the eld and added richness to the blues in the sky.

C

In the nested Luminance tab, we lightened
the Oranges and Yellows and darkened the
Blues. A negative Blues adjustment can pro-
duce an eect similar to a polarizing lter
used during a photo shoot.

D
 e L u m i n a n c e a d j u s t m e n t s l i g h t e n e d t h e c o l o r s i n t h e  e l d a n d
darkened the colors in the sky. Overall, the colors in the top part of this
photo are now in better balance with those in the lower part.
➤ Choose a zoom level of 66% for the Camera Raw preview to see
a more accurate rendering of the adjusted pixels.

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76 Chapter 4



All digital cameras produce some luminance (gray-
scale) noise and color artifacts. Although budget
cameras tend to produce the most noise, it can also
be produced by a high-end camera if used with a high
ISO (light sensitivity) setting to capture a poorly lit
scene. Before opening your photo into Photoshop,
you should try to remove as much noise from it as
possible, as it can become accentuated by image edit-
ing. When you follow these instructions, you’ll see
that shifting one slider value often requires adjusting
another.
To reduce luminance and color noise using

the Detail tab:
★
1. With a photo open in Camera Raw (
A
, next
page), click the Detail tab and choose a zoom
level of 200–300% for the preview.
2.
To reduce grayscale noise (graininess), increase
the Luminance value (
B
, next page). Try a value
between 20 and 70.
3.
Raising the Luminance value smoothed out the
high-contrast edges in the photo. To resharpen
those edges, raise the Luminance Detail value
(
C
, next page). Note that a high Luminance
Detail value may reintroduce noise along the
edges.
➤ With the Hand tool (H), you can move the
photo in the preview window, to examine
dierent edges.
4.
Raise the Luminance Contrast value to restore
some edge contrast. e eect of this slider is
most noticeable in photos that contain a lot of
noise.

5.
Defects such as color artifacts and random speck-
ling tend to be most noticeable on solid-color
surfaces, particularly those in the shadow areas.
To reduce these defects, increase the Color value
from the default value of 25 to around 40–50,
depending on the subject matter of the photo.
6.
Raising the Color value may lower the intensity
of colors in areas of the photo that were poorly
lit. To restore some saturation and intensity to
those areas, increase the Color Detail value
(
D
, next page) from the default value of 50 to
around 75, or until the color saturation looks just
right. To judge the overall eect of the settings
you have chosen in this tab, lower the zoom level.
Using the Detail tab

Via sliders in the Detail tab, you can preview and
adjust the sharpness of your photo, and also reduce
any unwanted color noise. Using these nondestruc-
tive sharpening controls is the best way to apply
what is called capture, or input, sharpening.
To sharpen edges using the Detail tab:
1. Click the Detail tab
A
and choose a zoom
level of 100% for the preview. Note: If the words

“(Preview Only)” display in the Detail tab, click
the Open Preferences button in the toolbox.
In the Camera Raw Preferences dialog, choose
Apply Sharpening To: All Images, then click OK.
2. In the Sharpening area, use the Amount slider
to adjust the edge denition. For subject matter
that needs a lot of sharpening, such as hard
objects or architecture, set this slider to 100; if
less sharpening is needed, try a value of 50–60.
➤ To evaluate sharpening in a grayscale preview,
Alt-drag/Option-drag the Amount slider.
3.
Alt-drag/Option-drag the Detail slider slightly to
the right to sharpen edge details and textures,
and Alt-drag/Option-drag the Masking slider to
around 50 to protect low-contrast areas with a
black mask and sharpen only high-contrast areas.
A
In the Detail tab, we adjusted the
Sharpening sliders.

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Camera Raw 77

A
 i s i s a c l o s e - u p o f a p h o t o o f a s h o p w i n d o w
(viewed at a zoom level of 300%), with the Noise
Reduction: Luminance and Color sliders set to zero
(no noise reduction applied). Grayscale noise is
evident in the signage, and color artifacts are evi-

dent in the poorly lit interior behind the letters.



D
To remove color artifacts from the dark areas,
we increased the Color value to 60. is had the
eect of desaturating the colors, though, so to
revive the color saturation and intensity, our last
adjustment was to increase the Color Detail value
to 70. e nal image is shown at left.

B
To remove graininess from the letters, we
changed the Luminance value to 69, but this also
diminished the edge denition.
C
To resharpen the
edges of the letters, we
increased the Luminance
Detail value to 78.