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Distortion Filters

For the most part, commands in the Distort submenu are related by the fact that they move colors in an image to achieve unusual stretching, swirling, and vibrating effects. They're rather like the transformation commands in the Edit menu in that they perform their magic by relocating and interpolating colors rather than by altering brightness and color values.

The distinction, of course, is that whereas the transformation commands let you scale and distort images by manipulating four control points, the Distort filters provide the equivalent of hundreds of control points, all of which you can use to affect different portions of an image. In some cases, you're projecting an image into a fun-house mirror; other times, it's a reflective pool. You can fan images, wiggle them, and change them in ways that have no correlation to real life, as illustrated in Figure 11-13.

Figure 11-13: This is your image (left); this is your image on distortion filters (right). Six filters, in fact: Spherize, Twirl, Polar Coordinates, Shear, Wave, and Ripple. I also used Liquify for some of the effects toward the top of the image, including those Gollum-like eyes.

Distortion filters are powerful tools. Although they are easy to apply, they are extremely difficult to use well. Here are some rules to keep in mind:

Practice: Distortion filters are like complex vocabulary words. You don't want to use them without practicing a little first. Experiment with a distortion filter several times before trying to use it in a real project. You may even want to write down the steps you take so that you can remember how you created an effect.

Use caution during tight deadlines: Distortion filters are enormous time-wasters. Unless you know exactly how you want to proceed, you may want to avoid using them when time is short. The last thing you need when you're working under the gun is to get trapped trying to pull off a weird effect.

Apply selectively: The effects of distortion filters are too severe to inflict all at once. You can achieve marvelous, subtle effects, however, by distorting feathered and layered selections. Although I would hardly call the image in Figure 11-13 subtle, no single effect was applied to the entire image. For instance, the black edges were created with the Ripple filter. I also skipped ahead of myself a bit and used the Liquify command to create the distortion in the topmost face and in the main pair of eyes. The section "Distorting with the Liquify command" explains how to use this tool.

Combine creatively: Don't expect a single distortion to achieve the desired effect. If one application isn't enough, apply the filter again. Experiment with combining different distortions.

Reflecting an image in a spoon

Most folks take their first venture into distortion filters by using Pinch and Spherize. Pinch maps an image on the inside of a sphere or similarly curved surface; Spherize maps it on the outside of a sphere. It's sort of like looking at your reflection on the inside and outside of a spoon.

You can apply Pinch to a scanned face to squish the features toward the center or apply Spherize to accentuate the girth of the nose. Figure 11-14 illustrates both effects. It's a laugh, and you pretty much feel as though you're onto something that no one else ever thought of before. (At least that's how I felt — but I'm easily amazed.)

Figure 11-14: My kind and decent subject endures more humiliating abuse — thanks to the Pinch and Spherize filters. Notice how negative values make Pinch spherize, and Spherize pinch.

You can pinch or spherize an image using either the Pinch or Spherize command. Note that a positive Amount value in the Pinch dialog box produces an effect similar to a negative value in the Spherize dialog box. There is a slight difference between the spatial curvature of the 3-D calculations: Pinch pokes the image inward or outward using a rounded cone — we're talking bell-shaped, much like a Gaussian model. Spherize wraps the image on the outside or inside of a true sphere. As a result, the two filters yield subtly different results. Pinch produces a soft transition around the perimeter of a selection; Spherize produces an abrupt transition. If this doesn't quite make sense to you, just play with one, try out the same effect with the other, and see which you like better.

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 Figure 11-15. 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.

Figure 11-15: Spherize also lets you wrap your image around a horizontally (top row) or vertically (bottom row) oriented cylinder.

One of the more remarkable properties of the Pinch filter is that it lets you turn any image into a conical gradation. Figure 11-16 illustrates how the process works. 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 (z -F on the Mac), the center portion of the image recedes farther and farther into the distance, as shown in Figure 11-16. After 10 repetitions, the face in the example all but disappeared.

Figure 11-16: I pinched the image 10 times and applied the Radial Blur filter with its default settings to create a conical gradation.

Next, apply the Radial Blur filter set to Spin 10 pixels or so to mix the color boundaries a bit. The result is a type of gradation that you can't create using Photoshop's gradient tool.

Twirling spirals

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 Distort Twirl, you can enter a positive value from 1 to 999 degrees to spiral the image in a clockwise direction. Enter a negative value to spiral the image in a counterclockwise direction. Figure 11-17 shows a 30-degree spiral and a 100-degree spiral in both positive and negative directions. As you are probably already aware, 360 degrees make a full circle, so the maximum 999-degree value equates to a spiral that circles around almost three times, as shown in the bottom-right example in Figure 11-18.

Figure 11-17: You can adjust the direction of the Twirl filter to suit whichever side of the equator you happen to be on.

Figure 11-18: Our poor Pinch-headed subject (upper left) gets subjected to the tortures of the Twirl filter (upper right). Repeatedly applying the Twirl filter at a moderate value (bottom left) produces a smoother effect than applying the filter once at a high value (bottom right).

In addition to creating ice-cream swirls like those shown in Figure 11-18, you can use the Twirl filter to create organic images virtually from scratch, as witnessed by Figures 11-19 and 11-20.

Figure 11-19: You can create surprisingly naturalistic effects using distortion filters exclusively.

Figure 11-20: Although they appear as if they might be the result of the ZigZag filter, these images were created entirely by using the gradient tool, the Twirl filter, and a couple of transformations.

To create the images shown in Figure 11-19, I started with Mr. Pinch-head (top left) and used the Spherize filter to flex the image vertically by entering 100 percent in the Amount option box and selecting Vertical Only from the Mode pop-up menu. After repeating this filter several times, I eventually achieved a stalactite-stalagmite effect, as shown in the top-right example of the figure. To increase the contrast in the image, I applied Unsharp Mask and followed that up with a little Gaussian Blur to make things creamier. I then repeatedly applied the Twirl filter to curl the straight spikes like two symmetrical hairs. The result merges the simplicity of pure math with the beauty of bitmapped imagery.

Figure 11-20 illustrates a droplet technique designed by Mark Collen. I took the liberty of breaking down the technique into the following steps.

STEPS: Creating a Thick-Liquid Droplet

Press D to restore the default foreground and background colors.

Shift-drag with the rectangular marquee tool to select a square portion of an image.

Create a linear gradation by dragging inside the selection outline with the gradient tool. Before you drag, select the linear gradient style in the Options bar and select the foreground to background gradient from the Gradients drop-down palette, also in the Options bar. Drag a short distance near the center of the selection from upper left to lower right, creating the gradation shown in the top-left box in Figure 11-20.

Choose the Twirl filter and apply it at –360 degrees so that the spiral moves counterclockwise. To create the top-right image in the figure, I applied the Twirl filter three times. Each repetition of the filter adds another ring of ripples.

Press Ctrl+J (Win) or z -J (Mac) to copy the selection to a layer.

Choose Edit Transform Flip Horizontal.

Lower the Opacity value to 50 percent. You can do this from the keyboard by selecting the rectangular marquee tool and pressing 5. The result appears in the lower-left example in Figure 11-20.

Choose Edit Transform Rotate 90 CW. This rotates the layer a quarter turn, thus creating the last image in the figure. You can achieve other interesting effects by choosing Lighten, Darken, and others from the brush modes pop-up menu.

Now, if a few twirls and transformations can produce an effect this entertaining in black and white, just imagine what you can do in color. On second thought, don't imagine; check out Color Plate 11-4 instead. Starting with Photoshop's Blue, Red, Yellow gradient, I followed Steps 1 through 4. From there, I made extensive use of floating copies of layers with the Difference blend mode applied. Finishing up with a little Spherize, ZigZag, Lens Flare, and Unsharp Mask to mutate the concentric rings into something a little more interesting, the result was the whirlin', twirlin' work of art at the bottom of the color plate.

If that went a little fast for you, not to worry. More important than the specific effects is this general category of distortion drawings. A filter such as Pinch or Twirl permits you to create wild imagery without ever drawing a brushstroke or scanning a photograph. If you can do this much with a simple three-color gradation, just think of what you can do if you throw in a few more colors. Pixels are little more than fodder for these very powerful functions.

Creating concentric pond ripples

I don't know about you, but when I think of zigzags, I think of cartoon lightning bolts, wriggling snakes, scribbles — anything that alternately changes directions along an axis, like the letter Z. 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. 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. Go figure.)

When you choose Filter Distort ZigZag, Photoshop displays a dialog box offering the following options:

Amount: Enter an amount between negative 99 and positive 100 in whole-number increments to specify the depth of the ripples. If you enter a negative value, the ripples descend below the surface. If you enter a positive value, the ripples protrude upward.

To illustrate how the Amount value works, I first prepared the sample image pictured in Figure 11-21. Starting with our much-maligned Mr. Pinch as seen in the upper-left example (Oh, you're a lean one, Mr. Pinch), I copied the image to an independent layer, rotated it 180 degrees, and applied the Overlay blend mode (upper right). I floated this layer, used Overlay again, and applied the Twirl filter repeatedly (lower left). Finally, I pasted in the flag image seen earlier, inverted it, used the Difference mode on the layer, and flattened the entire image (lower right). Pretty cool, huh? Figure 11-22 shows the final image subject to the ZigZag filter with two different Amount values.

Figure 11-21: Mr. Pinch does his duty as a proud American, resulting in a kaleidoscopic sample image.

Figure 11-22: The results of applying the ZigZag filter using Amount values of 30 percent (top row) and 100 percent (bottom row) and each of the three Style settings. In all cases, the Ridges value was 5.

Ridges: This option box controls the number of ripples in the selected area and accepts any value from 0 to 20. Figure 11-23 illustrates the difference between a Ridges value of 5 (top row) and 20 (bottom row).

Figure 11-23: The effects of the ZigZag filter using two Ridges values and each of the three Style pop-up menu settings. In all cases, the Amount value was 50.

Style: The options in this pop-up menu determine how Photoshop moves pixels with respect to the center of the image or selection.

Around Center: Select this option to rotate pixels in alternating directions around the center without moving them outward, as shown in the left columns of Figures 11-22 and 11-23. This is the only option that produces what I would term a zigzag effect.

Out From Center: When you select this option, Photoshop moves pixels outward in rhythmic bursts according to the value in the Ridges option box. The middle columns of Figure 11-22 and 11-23 show some examples.

Pond Ripples: This option is really a cross between the previous two. It moves pixels outward and rotates them around the center of the selection to create circular patterns. As demonstrated in the right columns of Figures 11-22 and 11-23, this option truly results in a pond ripple effect.

Creating parallel ripples and waves

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 Distort Ripple. Photoshop displays the Ripple dialog box, giving you the following options:

Amount: Enter 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 11-24.

Figure 11-24: The effects of three different Ripple filter Amount values.

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 11-25 shows an example of each Size option.

Figure 11-25: The effects of the three different Ripple filter Size settings.

Ocean Ripple and Glass

The Ocean Ripple and Glass filters are gifts from Gallery Effects. Both 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. But where the effects filters are concerned, interface design is as fickle and transitory as the face on the cover of Tiger Beat Magazine.

The Ocean Ripple filter's two parameters, Ripple Size and Ripple Magnitude, are illustrated in Figure 11-26. Compare the examples horizontally to observe an increase in Ripple Size values from 3 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 11-26: Raising the Ripple Size value spreads out the effect; raising the 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 11-27 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 11-27: For maximum privacy while showering, choose a Glass door with high Distortion and low Smoothness settings (upper right).

The Wave filter

Now that you've met the ripple family, it's time to ride the Wave. I've come to love this filter — I use it all the time — but it's complex enough to warrant its own book. It wouldn't be a very big book and no one would buy it, but you never know what a freelancer like me will do next. Keep an eye out for Wave Filter Bible at your local bookstore.

In the meantime, choose Filter Distort Wave (that's the easy part) to display the Wave dialog box shown in Figure 11-28. Photoshop presents you with the following options, which make applying a distortion every bit as easy as operating an oscilloscope:

Figure 11-28: The Wave dialog box lets you wreak scientific havoc on an image. Put on your pocket protector, take out your slide rule, and give it a whirl.

Number of Generators: Right off the bat, the Wave dialog box boggles the brain. A friend of mine likened this option to the number of rocks you throw in the water to start it rippling. One generator means that you throw in one rock to create one set of waves. You can throw in two rocks to create two sets of waves (see Figure 11-29), three rocks to create three sets of waves, and all the way up to a quarryful of 999 rocks to create, well, you get the idea. If you enter a high value, however, be prepared to wait a few years for the preview to update. If you can't wait, press Escape, which turns off the preview until the next time you enter a value in the dialog box.

Figure 11-29: 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.

Wavelength and Amplitude: Beginning to feel like you're playing with a ham radio? 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 11-30 demonstrates the difference between Wavelength and Amplitude.

Figure 11-30: With all other parameters set according to the specifications at the bottom of the figure, increasing Wavelength creates a larger horizontal distance between the peaks of waves. Increasing Amplitude creates a higher wave peak.

Scale: You can scale the effects of the Wave filter between 1 and 100 percent horizontally and vertically. For clarity's sake, all the effects featured in Figures 11-29 and 11-30 use only Vertical Scale, with Horizontal Scale set at the minimum of 1 percent. Increasing Horizontal Scale would make the waves go back and forth as well as up and down.

Type: You can select from three kinds of waves. As seen in Figures 11-29 and 11-30, the Sine option produces standard sine waves that rise and fall smoothly in bell-shaped curves, just like real waves. The Triangle option, shown in the first and third examples of Figure 11-31, creates zigzags that rise and fall in straight lines, like the edge of a piece of fabric cut with pinking shears. The Square option, illustrated in the second and last examples of Figure 11-31, 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 11-31 utilize a Number of Generators setting of 1; examples of the Triangle and Square types with higher Number of Generator values can be seen in Figure 11-32.

Figure 11-31: The effects of the unsmooth Triangle and Square types, using relatively high Wavelength and low Amplitude values (top two examples) versus relatively low Wavelength and high Amplitude values (bottom two examples).

Figure 11-32: Clicking Randomize rolls the dice and gives you another Wave effect based on the parameters you've set. Compare the first example to the second, and the third to the fourth.

Randomize: The Wave filter is random by nature. If you don't like the effect you see in the preview box, click the Randomize button (as illustrated in Figure 11-32) 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.

Distorting an image along a curve

The Distort command (Edit Transform Distort), which isn't discussed elsewhere in this book, creates four corner handles around an image. You drag each corner handle to distort the selected image in that direction. Unfortunately, you can't add other points around the edges to create additional distortions, which can be frustrating if you're trying to achieve a specific effect. If you can't achieve a certain kind of distortion using Edit Free Transform, the Shear filter may be your answer.

Shear distorts an image or a selection along a path. When you choose Filter Distort Shear, you get the dialog box shown in Figure 11-33. Initially, a single line that has two points at either end appears in the grid at the top of the box. When you drag the points, you slant the image in the preview. This, plus the fact that the filter is named Shear — Adobe's strange term for skewing (it appears in Illustrator as well) — leads many users to dismiss the filter as nothing more than a slanting tool. But in truth, it's more versatile than that.

Figure 11-33: Click the grid line in the left corner of the Shear dialog box to add points to the line. 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, 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 the Defaults button.

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 Wrap Around or repeat pixels along the edge of the selection by selecting Repeat Edge Pixels.

Changing to polar coordinates

The Polar Coordinates filter is another one of those gems that a lot of folks shy away from because it doesn't make much sense at first glance. When you choose Filter Distort Polar Coordinates, Photoshop presents a dialog box with two radio buttons, as shown in Figure 11-35. You can map an image from rectangular to polar coordinates or from polar to rectangular coordinates.

Figure 11-35: In effect, the Polar Coordinates dialog box enables you to map an image onto a globe and view the globe from above.

All right, time for some global theory. The first image in Figure 11-36 shows a stretched detail of a world map. This map falls under the heading of a Mercator projection, meaning that Greenland is all stretched out of proportion, looking as big as the United States and Mexico combined.

Figure 11-36: The world expressed in rectangular (top) and polar (bottom) coordinates. The decorative ornament atop the first image becomes a happy inhabitant of the North Pole in the second.

The reason for this has to do with the way different mapping systems handle longitude and latitude lines. On a spherical globe, lines of latitude converge at the poles. On a Mercator map, they run absolutely parallel. Because the Mercator map exaggerates the distance between longitude lines as you progress away from the equator, it likewise exaggerates the distance between lines of latitude. The result is a map that becomes infinitely enormous at each of the poles.

When you convert the map to polar coordinates (by selecting the Rectangular to Polar radio button in the Polar Coordinates dialog box), you look down on it from the extreme North or South Pole. This means that the entire length of the top edge of the Mercator map becomes a single dot in the exact center of the polar projection. The length of the bottom edge of the map wraps around the entire perimeter of the circle. The second example in Figure 11-36 shows the result. For this to be completely realistic, I would have to start with a map of just the top half of the globe, with the equator running along the bottom edge, but you get the idea. And as you can see, the Rectangular to Polar option is just the tool for wrapping text around a circle.

If you select the Polar to Rectangular option, the Polar Coordinates filter produces the opposite effect. Imagine for a moment that the image shown in the upper-left corner of Color Plate 11-5 gives the results in full color, with a morphing effect thrown in for good measure.

Figure 11-37: Two familiar circular images (left) converted from polar to rectangular coordinates (right). The top example is simple enough that you might be able to predict the results of the conversion in your head. The lower example looks cool, but you'd need a brain extension to predict the outcome.

Distorting with the Liquify command

The final essential distortion function isn't located under the Filter Distort submenu. In fact, in many respects, it's not a filter at all. The Liquify command is more of a separate distortion utility that just happens to run in Photoshop. It enables you to perform any number of distortions — you can warp, shift, twirl, expand, contract, and even copy pixels. It grants you multiple undos and redos before you apply the final effect. And unlike other distortion filters, which apply a uniform effect across a layer or selection, Liquify lets you modify pixels by pushing them around with a brush.

The result is a distortion filter that doubles as a powerful retouching tool. Consider the images in Figure 11-38. Raphael's original oil painting on left shows a lad who, in his day, was no doubt regarded as the perfect gentleman. But I worry that if he were to attempt to transport from his century to ours, his ways would be misunderstood. It might be his hairstyle, all curly on the sides but slicked down on top. Or it could be his languid expression, as if his delicate features had become lost in a torpid sea of big, round face. Then there's his raised pinky, which speaks perhaps too loudly of a young man who very much enjoys the feel of a dainty teacup in his hand. But whatever the culprit, I sense that this boy's presence would not receive warm applause and hearty handshakes were he to step onto a modern metropolitan thoroughfare or playground. In fact, there's the very real possibility that today's spirited teens would greet him with a vigorous beating and help themselves to his lunch money.

Figure 11-38: Using only the Liquify command, I was able to transform Raphael's 16th-century vision of St. Sebastian from a languid, matronly aristocrat (left) into a self-assured senior who managed to snag a part in the high school play (right).

But thanks to the Liquify command, I was able to transform Raphael's masterwork into the swaggering, ill-informed but fiercely opinionated high school graduate that we see on right. Oh sure, he still wears his hair long and likes to dress like his grandmother, but like any good Catholic boy, he's got the chutzpah to pull it off. There's still a bit of action in that pinky, but you know he's only doing that because it seems to irritate people.

Liquify basics

To enter the world of Liquify (sic) — oh, sorry, I forgot, I said I wasn't going to do that — choose the Liquify command from the Filter menu or press the keyboard shortcut Ctrl+Shift+X (z -Shift-X on the Mac). Photoshop displays the immense Liquify image window shown in Chapter 9) in its wealth of tools and options.

Figure 11-39: Choose Filter Liquify to shove pixels around in your image by dragging them with a brush.

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 two 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.

Photoshop The Brush Density setting determines how much feathering the edges of your cursor will have while you are creating your distortions. A smaller Brush Density setting means that effects will be 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 check box to make Photoshop adjust the tool pressure based on the amount of pressure you put on the pen stylus.

Photoshop 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 will apply to the area.

You can use the standard shortcuts Ctrl+plus to zoom in and Ctrl+minus to zoom out (z -plus and minus on the Mac). Use the scroll bars to reposition the image or press the spacebar to get the hand tool and drag the image inside the window. The Liquify window also provides zoom (Z) and hand (H) tools for your navigation pleasure.

If you select a portion of your image before choosing Filter Liquify, by default any deselected areas are considered frozen, which just means that they're unaffected by the distortion tools. You can freeze and then thaw — make available for editing — portions of the image as explained in the upcoming section, "Freezing and thawing pixels." You can even create partially frozen or thawed areas, which further limits the impact of the distortion tools. Photoshop CS has introduced a number of new ways to control which pixels are frozen and which are thawed. In addition to a selection, you can freeze and thaw pixels based on a combination of the transparency information in the image and even through a layer mask.

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, turn off the Show Mask check box.

If your image contains layers, you will see only the current layer against a transparent checkerboard background when you enter the Liquify window. To see other layers, turn on the Show Backdrop check box 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.

Photoshop Use the new 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 check box 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 check box. 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 the Save Mesh button. 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.

Oh, and by the way, save your mesh.

The Liquify tools

Okay, so much for the basics. I can see that you're itching to start mucking around in your pixels. 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 a lot like the smudge tool. But instead of smearing pixels, you're incrementally moving points in the mesh that distorts the image. The first example in Figure 11-40 shows a few large-scale changes made with a large brush and the default Pressure value. That's a lot of fun, of course, but it's only practical if you're trying to produce a caricature of Carrot Top, which, let's face it, no one wants to do. And yet, when used properly, the forward warp tool is the Liquify command's most practical tool. To create the second image, I used the forward warp tool set to a smaller brush size. But the biggest difference was in the length of my strokes. Instead of dragging, say, 10 to 20 pixels at a time, I dragged one or two pixels. As you can see, lots of little adjustments — in my case, somewhere in the neighborhood of 30 strokes — produces the best results.

Figure 11-40: 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.

Figure 11-41 shows how I curled the lad's hair using the twirl tool. Throughout, I pressed Alt (or Option) to change the twirl direction. In the first image, I clicked and held in each of 15 locations to create 15 distinct curls. Then I clicked and dragged between the curls to fill in the hair and achieve a more credible effect.

Figure 11-41: Here I used the twirl tool to curl St. Sebastian's hair. I started by clicking and holding in 15 locations to rough in the basic curls (left). Then I clicked and dragged between those curls to fill in the effect (right).

Pucker (S): With that new keyboard shortcut (it used to be P), why not just rename this the sucker tool? Drag with this tool to suck pixels toward the center of the brush cursor. The effect is similar to applying the Pinch filter with a positive Amount value. If you 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 mouse down with this tool, pixels underneath the cursor move outward, like a stomach after too many trips to the buffet line. As is the case with the pucker tool, the longer you hold down the mouse button, the more bloating you get.

The pucker and bloat tools rock. In fact, I use them only slightly less frequently than the forward warp tool. They are particularly valuable for removing weight or adding bulk. For example, in the first image in Figure 11-42, I used the pucker tool exclusively to slim details in the image. I clicked and dragged around the jaw line. I also clicked and held on the nose and mouth and around the chin. The result is an increasingly feminine version of the one-time man. In the second image, I completed the operation by bloating the eyes, eyelids, and lips. I guess it just goes to show you — there aren't that many planets between men and women after all, just Pucker and Bloat.

Figure 11-42: Armed with the pucker tool, I clicked and dragged along the jaw, chin, nose, and mouth (left) to reduce the masculine elements of what had become a fairly meaty guy. Then I pressed Alt (Option on the Mac) and moused down on the eyes, eyelids, and lips to fill out his feminine attributes.

Push left (O): As you 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 the Alt key (Option on the Mac).

Mirror (M): Dragging with this tool creates a reflection, albeit one you might see in a funhouse 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 11-44. Press the Alt key (Option on the Mac) to reflect from another direction on-the-fly.

Figure 11-44: Using the mirror tool, I dragged up on the left side of the woman and down on her 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 11-45 illustrates a few examples. For purposes of demonstration, all four images were created using a very large Brush Size, 400, and the maximum Pressure value, 100. For each image in the top row, I held the brush in place for 15 seconds. The random variations built up from one moment to the next. Not surprisingly, a Turbulent Jitter value of 30 produced a more dramatic effect than one of 10. But things become a bit more complicated when you drag with the tool. For each image in the bottom row, I created two brushstrokes from the bottom of the image to the top, once on the right side of the face and again on the left. This time, the higher Turbulent Jitter value produces more random fluctuation, but both images result in roughly equivalent amounts of distortion, as dictated by the fixed Size and Pressure values.

Figure 11-45: Four variations 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). Throughout, the Size and Pressure were set to 400 and 100, respectively.

After all that, what good is the tool? When combined with low Turbulent Jitter values, I find it helpful for introducing small tremors, or turbulence, into an image. At higher values, 30 and up, things go haywire very quickly.

After you drag with any of these tools, you can undo the effect by pressing Ctrl+Z (z -Z on the Mac). You also have the option of multiple undos. Press Ctrl+Alt+Z (z -Option-Z on the Mac) to backstep through your operations. Press Ctrl+Shift+Z (z -Shift-Z) to redo undone distortions. To learn how to go back in time nonsequentially and explore additional reversion options, read the section "Reconstructing and restoring."

Freezing and thawing pixels

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 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 towards the outside of the brush. To freeze the entire image, click the Mask All button 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 the None button in the Mask Options settings.

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.

Reconstructing and restoring

In the Reconstruct Options section of the Liquify window, you see a Mode pop-up menu plus two buttons, Reconstruct and Restore All. You can use these options not only to revert an image to the way it looked before you applied a distortion, but also to redo a distortion so that it affects the image differently.

The following list outlines reversion possibilities:

Undo: The Liquify window doesn't give you a History palette, but Ctrl+Alt+Z and Ctrl+Shift+Z still let you undo and redo sequences of operations. (That's z -Option-Z and z -Shift-Z on the Mac).

Reset: To return everything back to the way it was the very first time you opened the Liquify window, Alt-click (Win) or Option-click (Mac) the Cancel button, which changes to Reset. Not only do you restore your original image, you restore the Liquify window's default settings.

Restore All: To revert the image without resetting all values to their defaults, click the Restore All button. This affects frozen and thawed areas alike.

Liquify also offers a handful of reconstruction techniques that are more controlled and more complex than the reversion options. By selecting an option from the Mode menu and then clicking the Reconstruct button or dragging with the reconstruct tool (R), you can reconstruct a distortion so that it extends from a frozen area into neighboring unfrozen pixels. The Reconstruct button affects all unfrozen areas, but dragging with the tool alters only pixels under your cursor, subject to the Brush Size and Pressure values.

Revert: The Revert mode restores unfrozen portions of the image to their original appearance, without regard to the borders between the frozen and unfrozen areas. Compare this to the Revert button, which restores frozen and unfrozen areas alike.

Rigid: This mode extends the distortion only as needed to maintain right angles in the mesh where frozen and unfrozen areas meet. The result is unfrozen areas that look very much like they did originally but smoothly blend into the frozen areas.

Stiff: Stiff interpolates the distortion so that the effect tapers away as you move farther from the boundary between the frozen and unfrozen areas.

Smooth and Loose: These two modes extend the distortion applied to the frozen areas into the unfrozen areas. The Smooth setting tries to create smooth transitions between frozen and unfrozen areas. Loose shares more of the distortion from the frozen area with the unfrozen area. You'll achieve the most dramatic results when frozen and unfrozen areas have been distorted differently.

Displace, Amplitwist, and Affine: The last three modes work exclusively with the reconstruct tool. Using these modes, you can apply one or more distortions that are in force at a specific reference point in the image. Click to set the reference point and then drag through unfrozen areas to distort them. Use the Displace mode to move pixels to match the displacement of the reference point; select Amplitwist to match the displacement, rotation, and scaling at the reference point; and choose Affine to match all distortions at the reference

Although Liquify certainly gives you plenty of ways to reconstruct distortions, predicting the outcome of your drags with the reconstruct tool can be nearly impossible. So be prepared to experiment. And if you don't get the results you want, remember that you can undo a reconstruction just as easily as you can a distortion.