Tài iệu Photoshop cs5 by Dayley part 95 doc

Right-click the new layer, and select Convert to Smart Object from the pop-up menu shown in Figure 20.14.. Select Filter ➪ Artistic ➪ Watercolor to apply a Watercolor filter to the Smar

FIGURE 20.12

Moving the Accented Edges effect below the Splatter effect can change the end result on the image

dramatically

Using Smart Objects to Make Non-Destructive Filter Adjustments

Applying filters directly to your images changes the actual pixel values and modifies the original data Although you can use the History option to get back to the original state, after you save your file, those pixels have been altered beyond recovery Additionally, you may need to try several filter methods and sometimes combinations of filters to get the adjustment you are looking for, which is hard to do when you are trying to apply more than one filter, especially if some of your filters are not found in the Filter Gallery

That is where Smart Objects can make a huge difference When you apply a filter to a Smart Object, it is applied as a Smart Filter that can be turned on and off, adjusted, reordered, and easily removed without destroying the underlying pixel data

layer into a Smart Object layer, but if you keep the background layer around, you can always cre-ate a new dupliccre-ate layer lcre-ater to try another set of Smart Filters on Use these steps to crecre-ate a duplicate of the background layer and then apply Smart Filters to it:

1 Open the image in Photoshop.

2 Right-click the background layer, and select Duplicate Layer from the pop-up menu

shown in Figure 20.13.

This displays the Duplicate Layer dialog box

3 Name the layer in the Duplicate Layer dialog box, shown in Figure 20.13, and click

OK to create the layer.

The new layer is added to the Layers panel

FIGURE 20.13

By creating a second layer, the original layer is preserved in its original state

4 Right-click the new layer, and select Convert to Smart Object from the pop-up menu

shown in Figure 20.14.

The layer is converted to a Smart Object, and the layer thumbnail includes a Smart Object icon as shown in Figure 20.14

5 Select Filter ➪ Artistic ➪ Watercolor to apply a Watercolor filter to the Smart

Object When the Filter Gallery open, make adjustments to the filter and click OK

The Watercolor filter is applied as a Smart Filter to the Smart Object, as shown in Figure 20.15

FIGURE 20.14

A Smart Object has a Smart Object icon on the layer thumbnail

FIGURE 20.15

When a Smart Filter is applied to a Smart Object, it becomes a sublayer, easily viewable and editable

6 Select Filter ➪ Brush Strokes ➪ Accented Edges to apply the Accented Edges filter to

the Smart Object When the Filter Gallery opens again, make adjustments to the

FIGURE 20.16

Additional filters appear on the Layers panel, with the most recent one on top

7 Drag and drop the Accented Edges filter below the Watercolor filter to change the

look of your image, as shown in Figure 20.17.

FIGURE 20.17

With a simple drag and drop, the order of the filters has been changed, changing the effect on the image

8 Make other changes to your filters as you desire by right-click any Smart Filter to

display the menu shown in Figure 20.18

You can choose any of these menu options, or you can perform these functions by doing

the following: Edit the filter settings by double-clicking the filter name Double-click the Blending Options icon (to the right of the filter name) to change the Blend mode of that filter over your image You also can disable the filter by clicking the “eye”-con Or you can delete the filter entirely by dragging the filter to the trash icon

FIGURE 20.18

Smart Filters are easily editable as well as non-destructive

Creating a Custom Filter

One of the most powerful filters Photoshop provides is the Custom filter The Custom filter gives you the ability to define most of the behavior of Photoshop’s filter algorithms Most of Photoshop’s filtering algorithms work by focusing on one pixel at a time Photoshop evaluates the ness of the surrounding pixels and uses various algorithms to calculate what the new color/bright-ness of the current pixel should be Then the algorithm moves to the other pixels until it has filtered every pixel in the image

Note

Many of Photoshop’s filtering algorithms apply multiple filtering effects and even additional algorithms that are

not available through the Custom filter You can get some pretty good results with the Custom filter, but you

cannot duplicate the results you can get in some of the other filters in Photoshop n

Applying a Custom filter is done by selecting Filter ➪ Other ➪ Custom from the main menu in Photoshop to launch the Custom dialog box shown in Figure 20.19 The Custom dialog box allows you to apply a weight to each of the neighboring pixels as well as the surrounding pixels when cal-culating the replacement pixel value

l Offset: The Offset value allows you to give an overall offset in brightness that is applied to

the resulting pixel Increasing the offset can compensate filters that tend to make the image too dark; decreasing the offset can compensate for filters that make the image too light

FIGURE 20.19

Using the Custom dialog box in Photoshop allows you to define filters by setting weights for surrounding

pixels, a scale value, and an offset value

Here’s how it all works Photoshop selects a pixel, multiplies it by the center value in the Custom filter, takes the surrounding pixels defined in the Custom filter, and multiplies them by the corre-sponding values Then it adds them all up, divides by the scale, and adds the offset to that number

This might be a bit confusing at first, but look at the example filter shown in Figure 20.19; con-sider a pixel with the value of 100, one pixel up is 200, one pixel down is 200, one pixel left is

150, and one pixel right is 150 This equation is used to calculate the value that replaces the cur-rent pixel:

(100x10+200x-1+200x-1+150x-1+150x-1)/5 + 0 = 60

Tip

A good rule of thumb when creating Custom filters is to try to make the value of the equation equal 1 if all of

the pixel values are set to 1 From there, you can tweak the values a bit and use the offset to adjust any major

problems.n

As you play around with the Custom filter tool, you start to realize the limitless possibilities of fil-ters you can create with it The following are some examples of different types of filfil-ters that can be created with the Custom filter tool shown in Figure 20.20:

l No Filter: Applying a value of 1 for the current pixel applies no filter.

l Sharpen: Applying negative values symmetrically to the surrounding pixels and a positive

value to the current pixel sharpens the image

l Blur: Applying positive values symmetrically to the surrounding pixels and a positive

value to the current pixel blurs the image and removes dust

l Directional Blur: Applying positive values in only one direction to the surrounding pixels and

a positive value to the current pixel blurs the image only in the direction of the pixel changes

l Enhance Edges: Applying positive values symmetrically to the surrounding pixels and a

negative value to the current pixel enhances edges in the image

l Highlight Edges: Applying negative values symmetrically to corner pixels and a negative

value to the current pixel highlights the edges in the image

l High Contrast: Applying extremely high values for both the surrounding pixels and the

current pixel results in a high-contrast effect

FIGURE 20.20

Some example Custom filters

Hightlight Edges Edge Detection

Directional Blur Blur

Sharpen

No Filter

Summary

This chapter presented a comprehensive listing of the artistic filters and learned how to apply them through the Filter menu and the Filter Gallery You learned more about Smart Filters and how they work to create a non-destructive sublayer on your image that can be edited, moved, or deleted

And if being able to use more than a hundred filters, add them to each other, and change their set-tings and blending modes doesn’t give you enough options, you can use the Custom filter setset-tings

to create just the look you want You should know how to do these things:

l Find the right artistic filter to get your desired results

l Use the Filter Gallery to apply a filter or multiple filters

l Create a Smart Object in order to add Smart Filters