Adobe Photoshop CS2 CLASSROOM IN A BOOK [Electronic resources] نسخه متنی

Improving performance with filters

Some filter effects can be memory-intensive, especially when applied to a high-resolution image. You can use these techniques to improve performance:

Try out filters and settings on a small portion of an image.

Apply the effect to individual channelsfor example, to each RGB channelif the image is large and you're having problems with insufficient memory. (With some filters, effects vary if applied to the individual channel rather than the composite channel, especially if the filter randomly modifies pixels.)

Free up memory before running the filter by using the Purge commands.

Allocate more RAM to Photoshop (Mac OS). You can also close other open applications to make more memory available to Photoshop.

Try changing settings to improve the speed of memory-intensive filters such as Lighting Effects, Cutout, Stained Glass, Chrome, Ripple, Spatter, Sprayed Strokes, and Glass filters. For example, with the Stained Glass filter, increase cell size. With the Cutout filter, increase Edge Simplicity, decrease Edge Fidelity, or both.

If you plan to print to a grayscale printer, convert a copy of the image to grayscale before applying filters. However, applying a filter to a color image and then converting to grayscale may not have the same effect as applying the filter to a grayscale version of the image.

1.

In the Layers palette, select the layer with the leaves image. Make sure that you select the layer itself and not the adjustment layer.

2.

Choose Filter > Brush Strokes > Accented Edges. In the upper right corner of the Accented Edges dialog box, set Edge Width to 1, Edge Brightness to 30, and Smoothness to 3. Then click OK to close the dialog box.

Using filters

To use a filter, choose the appropriate submenu command from the Filter menu. These guidelines can help you in choosing filters:

The last filter chosen appears at the top of the Filter menu.

Filters are applied to the active, visible layer.

Filters cannot be applied to bitmap-mode or indexed-color images.

Some filters work only on RGB images.

Some filters are processed entirely in RAM.

See "Using filters" in Photoshop Help for a list of filters that can be used with 16- and 32-bit-per-channel images.

1.

In the Layers palette, select the layer with the dandelion image.

2.

In the toolbox, select the Elliptical Marquee tool (), which is hidden behind the Rectangular Marquee tool ().

3.

Drag across the dandelion image to select most of the seed head and stem, but do not extend the selection to the borders of the image.

The selection restricts the area that the filter will affect within the dandelion-image layer. If the selection is too large, the border will also be wavy and start to overlap the other quadrants of the montage image.

4.

Choose Filter > Distort > ZigZag.

5.

At the bottom of the ZigZag dialog box, make sure that Pond Ripples is selected in the Style pop-up menu. Then, experiment with different settings for Amount and Ridges by dragging the sliders. (The example uses 10% for Amount and 11 for Ridges.)

6.

When you are satisfied with the result, click OK.

7.

Choose Select > Deselect, and then File > Save to save your work.

TOOL TIPS FROM THE PHOTOSHOP EVANGELIST

Julieanne Kost is an official Adobe Photoshop evangelist.

Using filter shortcuts

Try powerful shortcuts to help save time when working with filters:

To reapply the most recently used filter with its last values, press Ctrl-F (Windows) or Command-F (Mac OS).

To display the dialog box for the last filter you applied,press ctrl-Alt-F(Windows) or command-Option-F(Mac OS)

1.

Choose Select > Load Selection.

2.

In the Channel pop-up menu in the Load Selection dialog box, choose Right Pear and click OK.

3.

Repeat Step 2, but this time select Left Pear as the Channel and select the Add to Selection option. Click OK.

Now both pears are selected.

1.

Using the Zoom tool (), zoom in to the image so that the area where the two pears overlap fills the image window.

2.

In the toolbox, click the Quick Mask Mode button (), or press Q to select it with the keyboard shortcut.

Areas in the image that are not included in the selection appear with a red tint.

You can double-click the Quick Mask Mode button to open the Quick Mask Options dialog box, where you can change the opacity and color of the tint that indicates the unselected areas.

3.

Look closely at the area where the pears overlap to see if any red pixels are there.

4.

In the toolbox, make sure that the foreground and background colors are black and white, respectively, or click the small Default Foreground and Background Colors button to reset them.

5.

Select the Eraser tool () and drag it over the area between the two pears to erase any red that appears there. If necessary, you can adjust the diameter of the Eraser tool on the tool options bar. Continue erasing until there are no more red pixels in that area.

Leave the selection active for the next procedure.

1.

In the toolbox, click the Standard Mode button (), or press Q.

2.

Double-click the Zoom tool () so that the image is at 100%.

3.

Select the Rectangular Marquee tool (), which may be hidden under the Elliptical Marquee tool ().

4.

Move the pointer inside the pear selection and then drag the selection marquee (not the pear images) into the lower right quadrant, centering it over the sand image.

If you want to move the selection at exactly a 45-degree angle, start dragging and then hold down Shift. Release the mouse button first, then the Shift key.

Be careful not to deselect yet, because you'll need this selection for the next exercise.

1.

In the Layers palette, select the layer with the sand image.

2.

Choose Layer > New > Layer via Copy to create a new layer above the original sand layer, based on your combined selection. The new layer automatically becomes the active layer in the Layers palette, and the pears-shaped marquee disappears.

You can quickly create a selection marquee around a layer by Ctrl-clicking (Windows) or Command-clicking (Mac OS) the layer thumbnail in the Layers palette. You can try this with the new Layer 5 to make the pear marquee reappear. Before you continue with this lesson, choose Select > Deselect.

3.

At the bottom of the Layers palette, click the Add a Layer Style button () and then choose Pattern Overlay from the pop-up menu.

4.

Drag the Layer Style dialog box aside, as needed, so that you can see both the dialog box and the image window.

5.

Click the Pattern arrow (in the long, narrow button to the right of the thumbnail) to open the pattern picker, which displays smaller thumbnails of an assortment of patterns.

6.

Click the arrow button () to open the palette menu for the pattern picker, and choose Load Patterns.

[View full size image]

7.

In the Load dialog box, go to the Lessons/Lesson12 folder and select the Effects.pat file. Click Load. When the dialog box closes, notice the new pattern that appears as the last thumbnail in the pattern picker.

8.

Select the pattern thumbnail you added in Step 7. The pattern replaces the default pattern inside your pears selection. At this point, you can drag the pattern in the image window to adjust the area of the pattern that appears in the selectioneven with the Layer Style dialog box open.

9.

On the left side of the Layer Style dialog box, under Styles, select Inner Shadow to add that effect to the selection, and adjust the Inner Shadow options to your liking. (The example uses the default settings for Blend Mode, Opacity, and Angle, but uses 13 for Distance and 10 for Size.)

10.

You can continue to experiment with other styles and settings until you create results that you think are interesting. When you are satisfied with the results, click OK.

11.

Choose File > Save to save your work.

For specific information on individual filters, see Photoshop Help.

1.

Scroll down the Layers palette to the Background layer and click the eye icon () to hide that layer. If the Background layer is selected, select any other layer.

2.

From the Layers palette menu, choose Merge Visible.

Lesson 12, and you can close the Montage.psd and 12End.psd files.