Sử dụng photoshop cs5 part 50 potx

In the fol-lowing instructions, you’ll blur the whole image by applying the filter as a Smart Filter, then to bring a key area back into focus, remove the effect from part of the image b

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Applying the Motion Blur filter

One way photographers capture the blur of

motion (e.g., in sports or wildlife photography) is

by panning the camera as the subject is moving

In Photoshop, you can create a similar illusion of

motion by using the Motion Blur filter In the

fol-lowing instructions, you’ll blur the whole image by

applying the filter as a Smart Filter, then to bring

a key area back into focus, remove the effect from

part of the image by painting on the filter mask

To apply the Motion Blur filter to part of

an image:

1 Click an image layer and duplicate it by

pressing Ctrl-J/Cmd-J.A

2 Right-click the duplicate layer and choose

Convert to Smart Object

3 Choose Filter > Blur > Motion Blur The

Motion Blur dialog opens.B

4 Lower the zoom level for the preview Choose

a Distance value for the amount of blurring,

choose an Angle value for the direction of the

blur, then click OK.C

5 On the Layers panel, click the filter mask

thumbnail for the Smart Filters listing

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

the Options bar, choose a medium-sized Soft

Round brush and an Opacity of 80% Choose

black as the Foreground color

7. Paint over the area of the image that you want

to hide the Motion Blur effect from and restore

focus to (A–B, next page) Since your brush

isn’t at full opacity, you can repeat your strokes

in any area to hide even more of the motion

blur

8 If you have masked too much of the Motion

Blur effect, press X to make the Foreground

color white, then apply strokes to restore it

➤ To readjust the Motion Blur filter settings,

double-click the filter listing on the Layers

panel

A This is the original photo

B In the Motion Blur dialog, we chose a Distance value of 64 px and set the Angle dial to match the angle of the motorcycle.

C The Motion Blur filter was applied to the whole image.

B The final results convey fast motion We were careful not to remove the Motion Blur effect from the tires, since they would be moving too fast to stay in focus.

A We clicked the filter mask thumbnail on the Layers panel,

then applied strokes with black to hide the Motion Blur effect

Using the Sharpen tool

When used with the new Protect Detail option

checked on the Options bar, the Sharpen tool

enhances details without introducing noticeable

artifacts With this tool, you can sharpen areas

selectively without having to use a mask Note: To

sharpen an entire image, see the remaining pages in

this chapter

To use the Sharpen tool: ★

1 Click an image layer, then duplicate it by pressing

Ctrl-J/Cmd-J.C

2 Choose the Sharpen tool.

3 On the Options bar, choose a Strength value,

and check Sample All Layers and Protect Detail.

4 Press [ or ] to adjust the brush diameter, then

drag across any area that needs sharpening.DFor

stronger sharpening, drag again in the same area

C This photo has a soft focus.

D With the Sharpen tool, we easily sharpened just the eyes.

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To apply the Smart Sharpen filter:

1 Open a photo that needs sharpening AOn the Layers panel, click an image layer or the Back-ground, then press Ctrl-J/Cmd-J to duplicate

it Right-click the duplicate layer and choose

Convert to Smart Object

2 Choose Filter > Sharpen > Smart Sharpen The

Smart Sharpen dialog opens Move it out of the way so the document is still in view

➤ Keep the zoom level for the preview at 67%

or 100% To bring a different area of the image into view, either drag in the preview

or click in the document

3 Check More Accurate to produce high-quality

sharpening by allowing multiple passes of the filter This takes longer but is worth the wait

4 From the Remove menu, choose an algorithm

for the correction: Gaussian Blur is a good, all-purpose choice; Lens Blur sharpens details with fewer resulting halos (we like this option); and Motion Blur is useful for correcting blurring due to movement of the camera or subject, but for this option you need to know that angle of movement

Applying the Smart Sharpen filter

Most digital photos need to be sharpened, and

the need becomes greater if you change the file’s

dimensions or resolution with the Resample Image

option checked, convert it to CMYK Color mode, or

apply a transformation command to it

To sharpen an image, you can use either the

Smart Sharpen filter or the Unsharp Mask filter

(the latter, despite its name, has a sharpening

effect) These filters can add noise to an image and

therefore should be applied after image-editing,

adjustment, and color correction

High-resolution printing also causes some minor

blurring due to dot gain You can anticipate and

compensate for this by sharpening the image once

again as you prepare it for output Experience will

teach you how much sharpening is needed

The Smart Sharpen filter, discussed first, gives

you the ability to sharpen (and fade the

sharpen-ing) in the shadow and highlight areas separately,

whereas Unsharp Mask (see pages 299–300)

doesn’t provide that control We usually use the

Smart Sharpen filter for targeted sharpening and

the Unsharp Mask filter for output sharpening

(See also the sidebar below.)

A Because the Smart Sharpen filter will let us control which tonal areas in the image are sharpened, it will be the right choice for correcting this blurry portrait (the resolution of this image is 300 ppi).

ADVANTAGES TO USING THE

SMART SHARPEN FILTER

We use both the Smart Sharpen and

Unsharp Mask fi lters on a regular basis

Smart Sharpen offers the following

advantages, though, in addition to the

one mentioned in the paragraph above:

➤ With the More Accurate option

checked, Smart Sharpen applies

sharp-ening in multiple passes

➤ Smart Sharpen has the ability to

detect edges, so it produces fewer

color halos than Unsharp Mask

➤ Smart Sharpen lets you choose from

three algorithms (to correct Gaussian

blur, lens blur, or motion blur),

whereas Unsharp Mask corrects only

Gaussian blur

➤ Smart Sharpen lets you save and

reuse your settings, for greater speed

and consistency in your workfl ow

5 Try an Amount value of 60–150% for the

degree to which contrast will be increased, and

a Radius value between 1 and 2.5 pixels You

can use the scrubby slider for all the sliders in

this dialog The image should now look slightly

oversharpened.AYou’ll fade the effect next

6. To control the amount of sharpening in the

shadow and highlight areas, click Advanced,

then click the Shadow tab BDrag in the

pre-view to display an area of the image that

con-tains both shadows and midtones, then make

the following adjustments:

Choose a Radius value (between 5 and 10) to

control how many neighboring pixels will be

compared to a specific pixel The higher the

Radius, the larger the area to be compared

Change the Tonal Width value to control the

range of midtones to be affected by the Fade

Amount The higher this width, the wider the

range of midtones affected and the more

gradu-ally the sharpening will fade into the shadows

Move the Fade Amount slider until you see

the desired reduction of oversharpening in the

Continued on the following page

A The settings we chose in the Basic panel of the Smart Sharpen dialog (shown above) successfully sharpened key details in

the photo, such as the eyes and lips, but in the process, also oversharpened the skin (now the pores look too pronounced).

B In the Shadow tab (Advanced panel), we chose a moderate Fade Amount to soften the sharpening in the shadows (such as around the eyes) and a moderate Tonal Width value to fully sharpen the shadows but only partially sharpen the midtones.

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A Finally, in the Highlight tab of the Smart Sharpen dialog, we chose a moderate Fade Amount to soften the sharpening in the broad, flat highlight areas of skin and a moderate Tonal Width value to fully sharpen the highlights and partially sharpen the light midtones.

B Compare this original image to the final image

at right.

C The Smart Sharpen filter added clarity to the facial features without applying unflattering sharpening to the cheeks and forehead.

shadows If the Tonal Width value is too low,

the effectiveness of this slider will be limited

7 Click the Highlight tab ADrag the image in

the preview to display an area that contains

both highlights and midtones Adjust the

Radius, Tonal Width, and Fade Amount

values, as in the preceding step

8 Hopefully, just the key details or features of

the image are sharper If the overall image now

looks too sharp, click the Sharpen tab and

reduce the Amount value slightly.

9 Click OK B–C

➤ To save the current settings as a preset, click

the Save a Copy button in the dialog, enter

a name, then click OK Saved settings can be

chosen from the Settings menu for any image

➤ To compare the unsharpened and sharpened

versions of the image, press on the dialog

preview, then release

➤ To modify the Smart Sharpen results,

double-click the Smart Sharpen listing on the Smart

Object layer; the dialog reopens

Applying the Unsharp Mask filter

To do its job of sharpening an image, the Unsharp

Mask filter increases the contrast between adjacent

pixels You will need to choose three variables in the

dialog: Amount, Radius, and Threshold

To apply the Unsharp Mask filter:

1 Choose a zoom level of 50–100% for your image,

then duplicate an image layer (Ctrl-J/Cmd-J).A

2 Right-click the duplicate layer and choose

Convert to Smart Object.

3. With the Smart Object layer selected, choose

Filter > Sharpen > Unsharp Mask The Unsharp

Mask dialog opens Move it out of the way, if

nec-essary, so the document is still in view

4 Choose an Amount percentage to control how

much the contrast is increased Use a low setting

(try 80–100) for figures or natural objects or a

higher setting (150–170) for sharp-edged objects

For a high-resolution image (2000 x 3000 pixels

or higher), try an Amount of 130–170.B

➤ Uncheck, then recheck Preview to compare

the original and sharpened images Choose

a zoom level for the preview of 50–100%

To bring a different area of the image into

view, either drag in the preview or click in

the document

5 The Radius affects how many neighboring pixels

around high-contrast edges the filter affects

When choosing an appropriate Radius, you need

to consider the pixel count of the image and its

subject matter.CThe higher the pixel count, the

higher the Radius value needed to achieve the

desired result For a low-contrast image that

contains large, simple objects and smooth

transi-tions, try a high Radius of 2 (you’ll rarely need

to use a higher value), whereas for an intricate,

high-contrast image containing many sharp

tran-sitions, try a lower Radius of around 1

Note: The Amount and Radius settings are

inter-dependent, meaning if you raise the Radius,

you’ll need to lower the Amount, and vice versa

6 Choose a Threshold value (0–255) to establish

how different in value an area of pixels must be

from a high-contrast edge to be affected by the

filter (A, next page) Start with a Threshold value

of 0 (to sharpen the entire image), then increase

Continued on the following page C …and a high Radius value of 3.3 produced halos

around the watch hands and numerals.

A The original 300 ppi image is slightly blurry

B A high Amount percentage for the Unsharp Mask fil-ter produced halos along the edges

of the watches…

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it slowly At a Threshold of 5–10, high-contrast

areas will be sharpened and areas of lesser

contrast will be sharpened much less When

increasing the Threshold, you can also increase

the Amount and Radius to sharpen the edges

Thankfully, the filter won’t oversharpen the

low-contrast areas

7. Click OK.B To adjust the settings at any time,

double-click the Unsharp Mask listing on the

Layers panel

➤ If the sharpening produced color halos along the

edges of the objects, choose Luminosity as the

blending mode for the Smart Object layer This

will limit the sharpening to luminosity values

and remove it from hue and saturation values

B The values shown above (note especially the lower Threshold value) produced this final, and

properly sharpened, version of the image.

A With a high Threshold value of 12 chosen in the Unsharp Mask dialog, the filter sharpened

only high-contrast edges but left the watchbands and background still blurry.

SUGGESTED SETTINGS FOR UNSHARP MASK

For an image that is 2000 x 3000 pixels or larger, try using these values:

Soft-edged subjects, such as landscapes

Amount 100–150, Radius 1–1.5, Threshold 6–10

Portraits Amount 100–120, Radius

1–2, Threshold 4–6, or to the point where skin areas start to look smoother

Buildings, objects, etc for which contrast is a priority

Amount 150–200 or more, Radius 1.5–3, Threshold 0–3