Some filters don't belong in either the corrective or destructive camp. Take Filter

The NTSC Colors filter modifies the colors in your RGB or Lab image for transfer to videotape. Vivid reds and blues that might otherwise prove very unstable and bleed into their neighbors are curtailed, as are pure white and black. The problem with this function is that it's not an independent color space; it's a dialog box-less filter (meaning you can't control it) that changes your colors and is finished with them. If you edit the colors after choosing the command, you may very well reintroduce colors that are incompatible with NTSC devices and therefore warrant a second application of the filter. Conversion to NTSC — another light-based system — isn't as risky as conversion to CMYK pigments, but you may wish you could have better results than this filter gives you.

The Offset command moves an image a specified number of pixels. Why wasn't it covered in Chapter 8 with the other movement options? Because the command moves the image inside the selection outline while keeping the selection outline itself stationary. It's as if you had pasted the entire image into the selection outline and were now moving it around. The command is a favorite among fans of channel operations, a topic covered in Chapter 4. You can duplicate an image, offset the entire duplicate by a few pixels, and then mix the duplicate and original to create highlight or shadow effects.

Note

Among the filters omitted in this chapter is Filter

As for the other filters in the Filter

Why bring this up here, in a chapter on filters? Because RAM (and your other system resources) is a precious commodity when applying destructive filters. As mentioned in Chapter 2, scratch disk space typically enables you to edit larger images than your computer's RAM might permit. But all the filters in the Distort submenu and most of the commands in the Render submenu operate exclusively in memory. If they run out of physical RAM, they won't work.

Here's what Adobe states are the minimum requirements for Windows users. Next to some of these requirements are our suggestions (in italics) for more realistic performance expectations:

If you're on a Mac, here are the system requirements — again, at minimum:

These requirements aren't intended to raise the hardware bar so high that only the wealthy can afford the computer that'll run Photoshop. It's just that the software's capabilities require more "juice" from the hardware, so only a computer with adequate resources can run it properly. If you're serious about your photos and all the things you can do with Photoshop, you probably already have a computer that can handle Photoshop's system requirements. If not, you'll reap lots of other technological benefits by upgrading your system — enhanced experience on the Internet, viewing video, and running lots of other programs that run faster and better with more horsepower under the hood.

A mezzotint is a special halftone pattern that replaces dots with a random pattern of swirling lines and wormholes. Photoshop's Mezzotint filter is an attempt to emulate this effect. Although not entirely successful — true mezzotinting options can be properly implemented only as PostScript printing functions, not as filtering functions — they do lend themselves to some interesting interpretations.

The filter itself is straightforward. You choose Filter

Note

The Mezzotint line patterns are on par with the halftoning options offered when you select Mode

When applied to grayscale artwork, the Mezzotint filter always results in a black-and-white image. When applied to a color image, the filter automatically applies the selected effect independently to each of the color channels. Although all pixels in each channel are changed to either black or white, you can see a total of eight colors — black, red, green, blue, yellow, cyan, magenta, and white — in the RGB composite view.

Figure 11.10. This figure shows the results of applying the Mezzotint filter as Fine Dots (upper left), Coarse Dots (upper right), Medium Lines (lower left), and Long Strokes (lower right). In each case, the filter changes all pixels in each channel to black and white.

If the Mezzotint filter affects each channel independently, it follows that the color mode in which you work dramatically affects the performance of the filter. For example, if you apply Mezzotint in the Lab mode, you again whittle the colors down to eight, but a very different eight — black, cyan, magenta, green, red, two muddy blues, and a muddy rose. If you're looking for bright happy colors, don't apply Mezzotint in the Lab mode.

In CMYK, the filter produces roughly the same eight colors that you get in RGB — white, cyan, magenta, yellow, violet-blue, red, deep green, and black. However, the distribution of the colors is much different. The image appears lighter and more colorful than its RGB counterpart. This happens because the filter has lots of black to work with in the RGB mode but very little — just that in the black channel — in the CMYK mode.

The Emboss filter works by searching for high-contrast edges (just like the Sharpen Edges and High Pass filters), highlighting the edges with black or white pixels, and then coloring the low-contrast portions with medium gray. When you choose Filter

Figure 11.11. The Emboss dialog box lets you control the depth of the filtered image (Height and Amount) and the Angle from which the image is lit.

The dialog box offers three options:

Photoshop provides three filters that trace around pixels in your image and accentuate the edges. All three filters live in the Filter

Like Mezzotint, Trace Contour applies itself to each color channel independently and renders each channel as a 1-bit image. A collection of black lines surrounds the areas of color in each channel. The RGB, Lab, or CMYK composite view shows these lines in the colors associated with the channels. When you work in RGB, a cyan line indicates a black line in the Red channel (no red plus full-intensity green and blue becomes cyan). A yellow line indicates a black line in the Blue channel, and so on. You get a single black line when working in the Grayscale mode.

The edge-tracing filters are especially fun to use in combination with Edit

Figure 11.14. Chrome can be very cool (left), but you may want to tone down its effects a bit with the Fade command (right). Here, the fine detail of the bird is retained, while on the left, the full chrome effect is distracting from the subject. The inset shows the original image.

Tip

There's no end to the ways you can tweak one filter by combining it with another filter (or two) and various image adjustments. For example, while on the topic of metallic coatings and the gleaming highlights they promise, could there be another way to achieve that look without the problems that the Chrome filter can create? Absolutely — and the Find Edges filter can help. First, copy your image to a separate layer by pressing Ctrl+J (

Just about everyone has stood in front of a fun-house mirror and watched his or her face and/or body be squeezed, stretched, and otherwise twisted into a variety of shapes. Where it gets really weird is where your facial features are shrunken, as though your face was shrinking from the center, and where your face seems to expand from the center — making for a big nose and a receding brow-bone and chin. It's probably fun to play in front of such a mirror for the same reason kids dress up like scary characters for Halloween — when something's temporary and unreal, even something scary can be fun. In Figure 11.16, you'll see a photo turned into a fun-house mirror reflection, using the Pinch and Spherize filters to scrunch, stretch, and wrap what started out as a perfectly normal-looking face.

Figure 11.16. Using Pinch and Spherize, you can create some amusing results. Notice how negative values can make Pinch spherize, and Spherize pinch?

Another difference between the two filters is that Spherize provides the additional options of enabling you to wrap an image on the inside or outside of a horizontal or vertical cylinder, as shown in the last sample in Figure 11.16, where Vertical Only was used. To try out these effects, select the Horizontal Only or Vertical Only options from the Mode pop-up menu at the bottom of the Spherize dialog box.

One of the more remarkable properties of the Pinch filter is that it lets you turn any image into a conical gradation. First, you may want to blur the image to eliminate any harsh edges between color transitions. Then apply the Pinch filter at full strength (100 percent). Reapply the filter several more times. Each time you press Ctrl+F (

The Twirl filter rotates the center of a selection while leaving the sides fixed in place. The result is a spiral of colors that looks for all the world as if you poured the image into a blender set to a very slow speed.

When you choose Filter

When you hear ZigZag filter, you may picture lightening bolts or other back-and-forth patterns. When it comes to a Photoshop filter, however, you know it won't be that simple. The ZigZag filter does arrange colors into zigzag patterns, but it does so in a radial fashion, meaning that the zigzags emanate from the center of the image like spokes in a wheel. The result is a series of concentric ripples, as shown in Figure 11.18 (see original image in the center inset). If you want parallel zigzags, check out the Ripple and Wave filters, described in the next section. (The ZigZag filter creates ripples and the Ripple filter creates zigzags — don't ask.)

Figure 11.17. You can adjust the direction of the Twirl filter and also increase its intensity.

When you choose Filter

Photoshop provides four means to distort an image in parallel waves, as if the image were lying on the bottom of a shimmering or undulating pool. Of the four, the ripple filters — which include Ripple, Ocean Ripple, and Glass — are only moderately sophisticated, but they're also relatively easy to apply. The fourth filter, Wave, affords you greater control, but its options are among the most complex Photoshop has to offer.

The Ripple filter

To use the Ripple filter, choose Filter

• Amount: Type an amount between negative 998 and positive 999 in whole-number increments to specify the width of the ripples from side to side. Negative and positive values change the direction of the ripples, but visually speaking, they produce identical effects. The ripples are measured as a ratio of the Size value and the dimensions of the selection — all of which translates to, "Experiment and see what happens." You can count on getting ragged effects from any value over 300, as illustrated in Figure 11.19.

• Size: Select one of the three options in the Size pop-up menu to change the length of the ripples. The Small option results in the shortest ripples and therefore the most ripples. Combining the Small option with a relatively high Amount value results in a textured-glass effect. The Large option results in the longest and fewest ripples. Figure 11.20 shows an example of each Size option.

  Tip

  You can create a blistered effect by overlaying a negative ripple onto a positive ripple. Try this: First, copy the selection. Then apply the Ripple filter with a positive Amount value — say, 300. Next, paste the copied selection and apply the Ripple filter at the opposite Amount value, in this case, −300. Press 5 to change the Opacity value to 50 percent. The result is a series of diametrically opposed ripples that cross each other to create teardrop blisters.

  

  Figure 11.19. This figure shows the effects of three different (increasing) Ripple filter Amount values. From the left, the Amount is set to 100 percent, then 300 percent in the middle, and finally 999 percent at the right.

  

  Figure 11.20. Here are the effects of the three different Ripple filter Size settings — Small (left), Medium (middle), and Large (right). In all three sections, an Amount of 300 percent was used.

Ocean Ripple and Glass

Both of these filters emulate the effect of looking at an image through textured glass. These two distorters so closely resemble each other that they would be better merged into one. The Ocean Ripple filter's two parameters, Ripple Size and Ripple Magnitude, are illustrated in Figure 11.21. Compare the examples horizontally to observe an increase in Ripple Size values from 5 to the maximum of 15; compare vertically to observe an increase in Ripple Magnitude from 5 to the maximum of 20. As you can see, you can vary the Ripple Size value with impunity. But raise the Ripple Magnitude value, and you're looking through sculpted glass.

Figure 11.21. Raising the Ocean Ripple Size value spreads out the effect; raising the Ocean Ripple Magnitude adds more depth and contrast to the ripples.

The principal difference between Glass and Ocean Ripple is that Ocean Ripple uses one preset distortion texture, and Glass gives you four to choose from, plus it lets you load your own (similar to Texturizer). You can invert the texture — high becomes low, low becomes high — and also scale it to change its size relative to the layer you're distorting. Figure 11.22 uses the Tiny Lens texture throughout and demonstrates how different the effect can be depending on the Distortion and Smoothness settings. Compare the examples in the figure horizontally for proof that Distortion is perhaps the best-named parameter in all of Photoshop. Smoothness, on the other hand, is sort of like an "anti-Ripple Magnitude" setting. High Smoothness settings in Glass are analogous to low Ripple Magnitude settings in Ocean Ripple.

Figure 11.22. Need to keep that nosy neighbor from peeking in the bathroom window? Select Glass windows with high Distortion, and low Smoothness.

The Wave filter

To go from baby ripples to serious water damage, choose Filter

Figure 11.23. The Wave dialog box lets you decide how high the tide will rise as it undulates over your image.

• Number of Generators: Think of Generators as rocks tossed into still water. The more rocks you throw (one at a time), the more pools of outward-flowing concentric waves you get. If the rocks are close to each other, the waves intersect and flow through and bounce off one another. As shown in Figure 11.24, the more rocks you throw in, the more extreme and complex the results. If you type a very high value in this field, however, be prepared to wait a few years for the preview to update. If you can't wait, press Esc, which turns off the preview until the next time you type a value in the dialog box.

• Wavelength and Amplitude: The Wave filter produces random results by varying the number and length of waves (Wavelength) as well as the height of the waves (Amplitude) between minimum and maximum values, which can range from 1 to 999. (The Wavelength and Amplitude options, therefore, correspond in theory to the Size and Amount options in the Ripple dialog box.) Figure 11.25 demonstrates an increase in Wavelength and Amplitude.

  

  Figure 11.24. The only difference between the examples in this figure is in the Number of Generators. Adding generators increases random action by creating more intersecting waveforms.

• Scale: You can scale the effects of the Wave filter between 1 and 100 percent horizontally and vertically. Increasing Horizontal Scale makes the waves go back and forth as well as up and down.

• Type: You can select from three kinds of waves. The Sine option produces standard sine waves that rise and fall smoothly in curves, just like real waves. The Triangle option creates zigzags that rise and fall in straight lines, like the edge of a piece of fabric cut with pinking shears. The Square option has nothing to do with waves at all, but rather organizes an image into a series of rectangular groupings, reminiscent of Cubism. You might think of this option as an extension of the Mosaic filter. All examples in Figure 11.26 utilize a Number of Generators setting of 1 and demonstrate the Sine, Triangle, and Square settings.

  

  Figure 11.25. With all other parameters being equal (Generators: 1, Type: Sine, Horizontal Scale: 1%, and Vertical Scale 100%) — increasing your Wavelength value results in a larger distance between your peaks, while increased Amplitude make your peaks higher.

  

  Figure 11.26. Here you see the effects of the Triangle and Square wave types. The top two samples use high Wavelength and low Amplitude values. The bottom two samples use the reverse.

• Randomize: The Wave filter is random by nature. If you don't like the effect you see in the preview box, click Randomize (as illustrated in the bottom example in Figure 11.26) to stir things up a bit. You can keep clicking the button until you get an effect you like.

• Undefined Areas: The Wave filter distorts a selection to the extent that gaps may appear around the edges. You can fill those gaps by repeating pixels along the edge of the selection, as in the figures, or by wrapping pixels from the left side of the selection onto the right side and pixels from the top edge of the selection onto the bottom.

The Distort command (Edit

Shear distorts an image or a selection along a path. When you choose Filter

Figure 11.27. Click the grid line in the left corner of the Shear dialog box to add points to the line. Click and drag these points to distort the image along the curve.

You can add points to the grid line simply by clicking it. A point springs up every time you click an empty space in the line. Drag the point to change the curvature of the line, and distort the image along the new curve. To delete a point, click and drag it off the left or right side of the grid. To delete all added points and return the line to its original vertical orientation, click Defaults.

The Undefined Areas options work just as they do in the Wave dialog box (described in the preceding section). You can either fill the gaps on one side of the image with pixels shoved off the opposite side by selecting the Wrap Around option or repeat pixels along the edge of the selection by selecting the Repeat Edge Pixels option.

Tip

Although Shear was conceived to create horizontal distortions, you may find that you need to create a vertically based distortion instead. If you can't change the filter, why not change the image? Simply rotating the image on its side (Image

Figure 11.28. Don't like the effect that traditional shearing gives you? Turn it on its ear!

The Polar Coordinates filter is another one of those gems that lots of people shy away from because it doesn't make much sense at first glance. When you choose Filter

Figure 11.29. We've abused this guy in this chapter! Here he is in the Polar Coordinates dialog box, set to Rectangular to Polar.

When you convert the image to Polar Coordinates (by selecting the Rectangular to Polar option in the Polar Coordinates dialog box), you look down on it from an extreme aerial view. This means that the entire length of the image becomes a single dot in the exact center of the polar projection. If you select the Polar to Rectangular option, the Polar Coordinates filter produces the opposite effect — instead of the entire image becoming a dot in the center of the project, the image flows from a polar center outward, in a rectangular shape. Figure 11.30 gives you a little food for thought.

Tip

The Polar Coordinates filter is a great way to edit gradations. After drawing a linear gradation with the Gradient tool (as discussed in Chapter 6), try applying Filter

Figure 11.30. Here you see the effects of converting some images from polar to rectangular coordinates. Go, Fishboy!

The Lens Correction filter opens a very large dialog box, shown in Figure 11.31. Your image appears in the Preview area, with a grid as an overlay. You can turn the Preview and the Grid off (hide them) using the check boxes just down and to the right of the preview — but you'd be better off keeping them on, at least while you're tinkering with the settings on the right side of the dialog box.

The tools on the left side of the dialog box allow you to use your mouse to adjust the Lens Correction settings — from top to bottom, the Remove Distortion tool, Straighten tool, Move Grid tool, Hand tool, and Zoom tool either correspond with a slider on the right or help you control the Preview area. For example, if you prefer a more hands-on approach to using this filter, use the Remove Distortion tool to drag on the Preview of the image instead of dragging the Remove Distortion slider. You can adjust the Angle setting by dragging to draw a line on the Preview with the Straighten tool.

Figure 11.31. The Lens Correction filter dialog box allows you to correct lens relative flaws in your images or introduce them for dramatic effect.

Speaking of settings, your choices are as follows:

The final essential distortion function isn't located under the Filter

Liquify is a distortion filter that also doubles as a powerful retouching tool. Consider the images in Figure 11.36. Thanks to the Liquify command, a calm and serene face was contorted into a mix of angered agitation — yet you could use it in subtler ways to widen eyes, soften lips, reduce a double chin, or raise cheekbones. Liquify could turn us all into supermodels.

Liquify basics

To enter the world of Liquify, choose the Liquify command from the Filter menu or press the keyboard shortcut Ctrl+Shift+X (

Figure 11.36. From content to contorted, all with the Liquify command's exciting set of tools

The miniature toolbox on the left side of the window contains seven tools for distorting your image. You drag or click with the tools as explained in the next section. (You can even select tools from the keyboard, as indicated by keys in parentheses.) But before you begin, here are a few basic facts:

• All tools respond to the Brush Size setting on the right side of the window. Press the right and left bracket keys ([ and ]) to raise and lower the brush size by 2 pixels. This is a bit of a departure from Photoshop's standard painting tools, where pressing [ or ] routinely changes the brush size by 10 pixels or more. To change the brush size in the Liquify window more rapidly, press and hold [ or ]. Throughout, your cursor reflects the approximate brush size. Note, however, that most distortions affect the pixels at the center of the cursor more quickly than those on the perimeter.

• The Brush Density setting determines how much feathering the edges of your cursor have while you are creating your distortions. A smaller Brush Density setting means that effects are more localized to the center of the brush.

• The Brush Pressure option controls the impact of the tools as you drag across your image; higher values produce more pronounced effects. If you work with a pressure-sensitive tablet, select the Stylus Pressure option to make Photoshop adjust the tool pressure based on the amount of pressure you put on the pen stylus.

• Available when you use the reconstruct, Twirl clockwise, Pucker, Bloat, and Turbulence tools, the Brush Rate option controls the strength of these tools when you click on a particular area but keep the cursor still. The higher the Brush Rate setting, the faster distortions are applied to the area.

  

  Figure 11.37. Choose Filter

  

  Liquify to shove pixels around in your image by dragging them with a brush.

• You can use the standard shortcuts Ctrl+plus to zoom in and Ctrl+minus to zoom out (

  

• If you select a portion of your image before choosing Filter

  

  You Really Must Mesh

  As with other Save buttons found throughout Photoshop's myriad dialog boxes, the Save Mesh button may strike you as the kind of option that could prove useful every once in a while. Be that as it may, you should use it every time you use the Liquify command. Yes, every time. The last thing you should do, right before you click OK, is click Save Mesh. Why? Because Photoshop does not automatically keep track of your previous Liquify settings. So if you spend 15 minutes or so working in the Liquify window, click OK, and then decide that the distortion doesn't work exactly as you had hoped, you're left with two unpleasant options: Choose Liquify and try to tweak the image further, which can result in incremental damage to the detail, or undo the previous operation and start over. But if you saved the mesh, you always have that last distortion to come back to. And the beauty is, a mesh is purely mathematical until it's applied. So you can use one mesh as a jumping-off point for another without doing incremental damage. Pixels get involved only after you click OK. So don't forget to save your mesh. Got that?

• By default, frozen regions are covered with a red translucent coating, just like masked areas in the Quick Mask mode. You can change the appearance of the overlay by selecting a new color from the Mask Color pop-up menu at the bottom of the Liquify window. If you don't want to see the coating at all, deselect the Show Mask option.

• If your image contains layers, you see only the current layer against a transparent checkerboard background when you enter the Liquify window. To see other layers, select the Show Backdrop option in the bottom-right corner of the window. You can view all layers or select a specific layer from the nearby pop-up menu. The Opacity option controls how well you can see the other layers.

• Use the Mode pop-up menu in the Show Backdrop settings to specify exactly how the layer you're currently distorting interacts with the other layers in the image. Regardless of what you see, Photoshop lets you edit only the active layer.

• Select the Show Mesh option to display gridlines on top of the image. You can use the gridlines as a guide if you want to apply very precise distortions. You can even apply your distortions while viewing only the grid by deselecting the Show Image option. Set the grid size and color by selecting options from the Mesh Size and Mesh Color pop-up menus.

• You can save a distortion for later use by clicking Save Mesh. To use the mesh on a Mac or PC, the file name needs to end with the .msh extension. Click Load Mesh to load a distortion stored on disk. Note that Photoshop is smart enough to scale the mesh to fit the current image, so a mesh specifically designed for one image may turn out to be useful for another.

The Liquify tools

Okay, so much for the basics. You're itching to start, so here's how the distortion tools along the left side of the Liquify window work:

Forward warp (W): Drag to shove the pixels under your cursor around the image. At first, it may feel like the Smudge tool. But instead of smearing pixels, you're incrementally moving points in the mesh that distort the image. The first example in Figure 11.38 shows a few large-scale changes made with a large brush and the default Pressure value. When used properly, the Forward Warp tool is the Liquify command's most practical tool. To create the second image, the Forward Warp tool was set to a smaller brush size. But the biggest difference was in the length of the strokes. Instead of dragging, say, 10 to 20 pixels at a time, the brush was dragged just 1 or 2 pixels. As you can see, making lots of little adjustments — in this case, somewhere in the neighborhood of 30 strokes — produces the best results.

Figure 11.38. Making big strokes with the Forward Warp tool produces wacky results (left); short, careful drags give you more control (right). But you have to be patient. It took 6 strokes to make the big changes on left and about 30 to make the subtle changes on right — broadening the nose, expanding the lips, raising the chin, and lifting the eyelids and brows.

Twirl clockwise (C): Click or drag to spin pixels under your cursor in a clockwise direction, or to the right.

This tool's companion, the Twirl counterclockwise tool, no longer owns a slot in the Liquify toolbox. But you can still access the Twirl counterclockwise tool by pressing Alt (Option on the Mac) when you drag with the Twirl clockwise tool. You can press and release Alt in mid-drag to switch the Twirl direction on the fly. Figure 11.39 shows the Twirl tool used with Alt (Option on the Mac) to change the Twirl direction.

Figure 11.39. Here the Twirl tool was used, twirling in two directions, thanks to the Alt (Option) key.

Pucker (S): Click and drag with this tool to move pixels toward the center of the brush cursor. The effect is similar to applying the Pinch filter with a positive Amount value. If you move your mouse down instead of dragging, Photoshop steadily increases the extent of the distortion until you release the mouse button.

Bloat (B): When you drag or move your mouse down with this tool, pixels underneath the cursor move outward. As is the case with the Pucker tool, the longer you hold down the mouse button, the more bloating you get.

Tip

Press Alt (Option on the Mac) to toggle between the Pucker and Bloat functions on the fly.

The Pucker and Bloat tools are particularly valuable for removing weight or adding bulk. For example, in the first image in Figure 11.40, the Pucker tool was used to contort the face and head shape.

Push Left (O): As you click and drag with this tool, pixels underneath the cursor move in a direction perpendicular to your drag. For example, if you drag down, pixels flow to the right. Drag straight up, and pixels move to the left. To reverse the direction of the pixels, press Alt (Option on the Mac).

At first, the Push Left tool may seem unwieldy, resulting in dramatic and sometimes unpredictable movements. But you can control it using two techniques. First, reduce the Brush Pressure value to 25 or lower. Figure 11.41 illustrates the difference between drags performed using Pressure settings of 50 and 20. Second, try using the Push Left tool in a straight line by clicking at one point and Shift-clicking at another, as you might with Photoshop's painting and editing tools. The result is a neat line, great for reducing flab along straight elements, such as arms and legs.

Figure 11.40. Armed with the Pucker tool, click and drag along the facial contours to reshape in ways a plastic surgeon can only imagine.

Figure 11.41. Pushing things around lets you totally revamp a face, body, or any photographic content.

Mirror (M): Clicking and dragging with this tool creates a reflection, albeit one you might see in a fun-house mirror. As you drag, Photoshop copies pixels from the area perpendicular to the direction you move the cursor. So if you drag up, you clone pixels to the right of the cursor into the area underneath the cursor; drag down to clone pixels from left to right, as shown in Figure 11.42. Press Alt (Option on the Mac) to reflect from another direction on the fly.

Figure 11.42. Using the Mirror tool, drag up on the left side and down on the right side. Pixels are reflected in a clockwise direction.

Turbulence (T): The Turbulence tool is a variation on the Forward Warp tool that distorts pixels in random directions as you drag. When you select this tool, Photoshop grants you access to a third Tool Options value labeled Turbulent Jitter. If the Brush Size value controls how many pixels are affected at a time and Brush Pressure controls the strength of the stroke, Turbulent Jitter specifies just how much random variation is permitted. The minimum value of 1 causes the Turbulence tool to behave much like the Forward Warp tool; a maximum value of 100 mixes pixels in all directions.

Figure 11.43 illustrates a few examples. For purposes of demonstration, all four images were created using a very large Brush Size (ranging from 100 to 200, throughout all the samples) and the maximum Pressure value, 100. For each image in the top row, the brush was held in place for 15 seconds. The random variations built up from one moment to the next. Not surprisingly, a higher Turbulent Jitter value produced a more dramatic effect than a lower one.

Figure 11.43. Four variations were created using the Turbulence tool, twice holding the mouse in place (top row) and twice dragging with the tool on the left and right sides of the face (bottom row).

After you drag with any of these tools, you can undo the effect by pressing Ctrl+Z (

Freezing and thawing pixels

As mentioned earlier, if you make a selection in your image before choosing Filter

To freeze a portion of your image from the Liquify window, you have two options:

Freeze Mask (F): Press F to select the Freeze Mask tool, and then click and drag over areas that you want to protect. You can adjust the brush size and pressure as you can when working with the distortion tools. But in this case, the Brush Pressure setting determines how deeply frozen the pixels become. At anything less than 100 percent, the pixels become partially distorted when you drag over them with a distortion tool. If you set the pressure to 50 percent, the distortion is applied with half the pressure used in unfrozen areas. Likewise, the Brush Density setting controls how deeply pixels become frozen toward the outside of the brush. To freeze the entire image, click Mask All in the Mask Options settings.

Thaw Mask (D): To thaw areas that you have frozen from the Liquify window, once again making them slaves to the distortion tools, paint over them with the Thaw Mask tool. The tool options affect this tool just as they do the Freeze Mask tool. To thaw the entire image, click None in the Mask Options settings.

Tip

Just as you can invert a selection outline or invert a mask in the Quick Mask mode, you can click Invert All to quickly freeze any unfrozen pixels and thaw any frozen ones.

Among the more complex features in the Liquify dialog box are the Mask Options settings, located below the Reconstruct Options. Above the None, Mask All, and Invert All buttons just mentioned, you're presented with five different buttons, each giving you a different option for interacting with the current mask. And each of those buttons has three options, when relevant; you can use information from the layer's current selection, transparency, or layer mask. From left to right, the options perform these functions:

• Replace selection replaces the current mask, completely wiping out any freezing or thawing you've done and replacing it with a mask drawn from the layer's current selection, transparency, or layer mask.

• Add to selection keeps all thawed areas in the current mask and also thaws other areas according to the layer's current selection, transparency, or layer mask.

• Subtract from selection keeps all frozen areas in the current mask and also freezes other areas according to the layer's current selection, transparency, or layer mask.

• Intersect with selection only allows an area to stay thawed if it is thawed both in the current mask and according to the layer's current selection, transparency, or layer mask.

• Invert selection takes the current mask and inverts it, but only within the thawed areas according to the layer's current selection, transparency, or layer mask.

The Vanishing Point filter, which really goes beyond what you expect from a filter, is used to manipulate image content to create the illusion of perspective. Of course, the Edit

Figure 11.44. The Vanishing Point dialog box provides tools for creating and editing planes, cloning, stamping, sampling, panning, and zooming in on your image.

There are some new features of the Vanishing Point filter for Photoshop CS3:

To use the Vanishing Point filter, read the discussion below to find out about the main tools and techniques.

When you start with the Vanishing Point tool, you want to begin with a duplicate layer that contains the portions of the image you want to use in creating the vanishing point and the content-in-perspective.

STEPS: Creating a vanishing point

The cloning process is very much the same as it is when using the Clone Stamp tool in the Toolbox — use Alt (Option on the Mac) and click to set the source for the clone. You'll want to use the Heal option (it appears at the top of the dialog box as soon as you begin using the Clone tool). This ensures the colors and lighting in the cloned content match their new surroundings. You also can leave Aligned on so that you don't create any unwanted patterns if cloning a large area.

With the Clone tool active, drag your mouse over the target area to draw content from the source point. As shown in Figure 11.47, the window from the front of the garage is cloned to the right side of the building, and it appears in perfect perspective. You can save your modifications to the duplicate layer by clicking OK, which closes the Vanishing Point window and returns you to your image.

Figure 11.47. The green cross hair (gray here, over on the left) indicates the source point for the Clone Stamp. And with no need for a home construction how-to manual, a new window is placed on this building in just minutes.

The Clouds filter creates an abstract and random haze between the foreground and background colors. The Difference Clouds filter works exactly like layering the image, applying the Clouds filter, and selecting the Difference blend mode in the Layers palette.

Why would Difference Clouds make special provisions for a single blend mode? Because you can create cumulative effects. Try this: Select a sky blue as the foreground color, and then choose Filter

Figure 11.48. These are the effects of applying Clouds (left), followed by Difference Clouds (middle) and Difference Clouds repeated 20 times.

Also, if you want to make a repeating texture using Clouds and Difference Clouds, make sure your image size is a square with pixel dimensions based on a power of two — something like 128×128 or 256×256 works well. Your cloudy image is seamlessly tiled, making it a perfect backdrop when you need something to fill in a large area.

Like the Clouds and Difference Clouds filters, the Fibers filter uses Perlin-based fractal noise to achieve a realistic randomness that, when stretched out in one direction, looks less like fluffy clouds and more like, well, fibers. This could be a problem for you if you don't want the fibers Photoshop gives you, because there is no way to vary the fibers greatly — you have two sliders (Variance and Strength) and one button (Randomize), and as you'll see, these don't do much more than change the appearance of the fibers — in the end, you still get fibers. If fibers are what you want, this is a great thing, but if you were hoping for a fibrous texture made from the content of your image, this is not what you're getting here. Programs such as Adobe's After Effects give you lots of options for tweaking and adjusting the noise this filter generates, but Photoshop's Fibers filter is rather limited in terms of its flexibility, and therefore its uses.

If you're still interested in using this filter — and you should be, if only to see for yourself how you might be able to use it — choose Filter

The complex Lighting Effects filter enables you to shine lights on an image, color, position, and focus the lights, specify the reflectivity of the surface, and even create a surface map.

When you choose Filter

Figure 11.49. Here's the Fibers filter dialog box and a preview of its effect on...well, anything.

There's no way around it: This filter and its dialog box are complex. The easiest way to apply the filter is to choose one of the predefined lighting effects from the Style pop-up menu at the top of the right side of the dialog box, see how it looks in the preview area, and — if you like it — press Enter or Return to apply the effect.

If you want to create your own effects, you have to tinker with the settings a bit and risk some frustration. It can be worth it, though, for creating some striking lighting effects in your images. Here are the basic steps involved in creating a custom effect.

Figure 11.50. The Lighting Effects dialog box lets you light an image as if it were hanging in a gallery, lying on a floor, or perhaps resting too near a hot flame.

STEPS: Lighting an image

That's really about it; the only parts not yet discussed are the Properties and Texture Channel options. The Properties sliders control how light reflects off the surface of your image:

The Texture Channel options let you treat one channel in the image as a texture map, which is a grayscale surface in which white indicates peaks and black indicates valleys. (This is true as long as the White is High option is selected, that is; if you deselect that option, everything flips and black becomes the peak.) It's as if one channel has a surface to it. By selecting a channel from the pop-up menu, you create an embossed effect, much like that created with the Emboss filter except much better because you can light the surface from many angles at once and it's in color, too.

Choose a channel to serve as the embossed surface from the pop-up menu. Then change the Height slider to indicate more or less Flat terrain or huge Mountainous cliffs of surface texture.

Figure 11.51 shows a rather bland multi-layered image — a metallic faceplate layer in front of a textured background layer. To add a little depth, a texture channel can be created for the faceplate layer by first Ctrl-clicking (

Now for the fun part! With the selection still in place, run the Gaussian Blur filter on it five times in a row using Radius values of 18, 9, 6, 3, and 1, in that order. What you've just created is a Depth map — the white area is the highest, and the fading edges are progressively lower, all the way down to the black zone (the lowest), as seen in Figure 11.52.

Figure 11.51. Nothing to write home about. But, just give us a sec...

Figure 11.52. After selecting the faceplate layer transparency and then hopping to a new alpha channel, we create this new Texture Map by applying the Gaussian Blur filter to the white fill inside the selection.

Figure 11.53 shows what happens when we apply the Lighting Effects filter to the faceplate layer and assign the texture map using the Texture Channel pop-up menu.

Figure 11.53. Now the faceplate has nicely lit beveled edges — better than those you'd get with the Bevel and Emboss layer styles, too. FYI: Sometimes the best texture map for an image is the image itself. We ran the same Lighting Effects filter on the background layer, using the Blue channel as the texture map.