Photoshop 6 for Windows Bible- P18

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Photoshop 6 for Windows Bible- P18:If you are reading this foreword, it probably means that you’ve purchased a copy of Adobe Photoshop 6.0, and for that I and the rest of the Photoshop team at Adobe thank you. If you own a previous edition of the Photoshop Bible, you probably know what to expect. If not, then get ready for an interesting trip.

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Chapter 10 ✦ Corrective Filtering 479 Averaging pixels with Median Another command in the Filter ➪ Noise submenu, Median removes noise by averaging the colors in an image, one pixel at a time. When you choose Filter ➪ Noise ➪ Median, Photoshop produces a Radius option box. For every pixel in a selection, the filter averages the colors of the neighboring pixels that fall inside the specified radius — ignoring any pixels that are so different that they might skew the average — and applies the average color to the central pixel. Photoshop 6 You can now enter any value between 1 and 100. However, even at the old limit, 16, significant blurring occurs, as you can see from the bottom-right example in Figure 10-41 (in the preceding section). At the maximum Radius value, you wind up with a sort of soft, blurry gradient, with all image detail obliterated. As with Gaussian Blur, you can achieve some very interesting and useful effects by backing off the Median filter with the Fade command. But rather than creating a Star Trek glow, Median clumps up details, giving an image a plastic, molded quality, as demonstrated by the examples in Figure 10-42. To create every one of these images, I applied the Median Filter with a Radius of 5 pixels. Then I pressed Ctrl+Shift+F to display the Fade dialog box and lowered the Opacity value to 70 percent. The only difference between one image and the next is the blend mode. Another difference between Gaussian Blur and Median is that Gaussian Blur destroys edges and Median invents new ones. This means you can follow up the Median filter with Unsharp Mask to achieve even more pronounced sculptural effects. I sharpened every one of the examples in Figure 10-42 using an Amount value of 150 percent and a Radius of 1.5. Sharpening a compressed image Digital cameras are the hottest thing in electronic imaging. You can take as many images as you like, download them to your computer immediately, and place them into a printed document literally minutes after snapping the picture. In the next five years, I have little doubt that you — yes, you — will purchase a digital camera (if you haven’t already). Unfortunately, the technology is still very young. And if you’re using one of the mid- or low-priced cameras — read that, under $500 — even the slightest application of the Unsharp Mask filter sometimes results in jagged edges and unsightly artifacts. These blemishes stem from a stingy supply of pixels, heavy-handed compression schemes (all based on JPEG), or both. The situation is improving; cameras at the high end of the consumer price range ($700 and up) can produce 3-megapixel images and often enable you to store uncompressed images in the TIFF format. But as with all good things in life, it will take a while for those options to be available in moderately priced equipment.
480 Part III ✦ Selections, Masks, and Filters Normal Screen Darken Lighten Figure 10-42: After applying the Median filter, I reversed the effect slightly using Edit ➪ Fade Median. Although I varied the blend mode — as labeled beneath the images — the Opacity value remained a constant 70 percent. In the meantime, firm up the detail and smooth out the color transitions in your digital photos by applying a combination of filters — Median, Gaussian Blur, and Unsharp Mask — to a layered version of the image. The following steps tell all. Note If you own a digital camera, I encourage you to record these steps with the Actions palette, as explained in Chapter B on the CD accompanying this book. This way, you can set Photoshop to open squads of images, batch-process them, and save them in a separate folder, leaving you free to do something fun, like read more of this book.
Chapter 10 ✦ Corrective Filtering 481 STEPS: Adjusting the Focus of Digital Photos 1. Select the entire image and copy it to a new layer. That’s Ctrl+A, Ctrl+J. Figure 10-43 shows the image that I intend to sharpen, a picture of a friend’s child. Figure 10-43: I captured this youthful fellow with a low-end digital camera equipped with a removable fish-eye lens. How innocent and happy he looks — obviously not a computer user. 2. Choose Filter ➪ Noise ➪ Median. After processing several thousand of these images, I’ve found that a Radius value of 2 is almost always the optimal choice. But if the image is particularly bad, 3 may be warranted. 3. Choose Filter ➪ Blur ➪ Gaussian Blur. Now that you’ve gummed up the detail a bit and rubbed out most of the compression, use the Gaussian Blur filter with a Radius of 1.0 to blur the gummy detail slightly. This softens the edges that the Median filter creates. (You don’t want any fake edges, after all.) 4. Choose Filter ➪ Sharpen ➪ Unsharp Mask. All this blurring demands some intense sharpening. So apply Unsharp Mask with a maximum Amount value of 500 percent and a Radius of 1.0 (to match the Gaussian Blur radius). This restores most of the definition to the edges, as shown in Figure 10-44. 5. Lower the layer’s Opacity value. By itself, the filtered layer is a bit too smooth. So mix the filtered floater with the underlying original with an Opacity value between 30 and 50 percent. I found that I could go pretty high — 45 percent — with Cooper. Kids have clearly defined details that survive filtering quite nicely.
482 Part III ✦ Selections, Masks, and Filters Figure 10-44: Thanks to Median, Gaussian Blur, and Unsharp Mask, Cooper is a much smoother customer. In fact, he’s beyond smooth — he’s a gummy kid. 6. Merge the image. Press Ctrl+E to send the layer down. 7. Continue to correct the image as you normally would. The examples in Figure 10-45 show the difference between applying the Unsharp Mask filter to the original image (top) and the filtered mixture (bottom). In both cases, I applied an Amount value of 200 percent and a Radius of 1.0. The top photo displays an unfortunate wealth of artifacts — particularly visible in the magnified eye — while the bottom one appears smooth and crisp. These steps work well for sharpening other kinds of compressed imagery, including old photographs that you over-compressed without creating backups, and images that you’ve downloaded from the Internet. If applying the Unsharp Mask filter brings out the goobers, try these steps instead. Cleaning up scanned halftones Photoshop offers one additional filter in the Filter ➪ Noise submenu called Dust & Scratches. The purpose of this filter is to remove dust particles, hairs, scratches, and other imperfections that may accompany a scan. The filter offers two options, Radius and Threshold. As long as the offending imperfection is smaller or thinner than the Radius value and different enough from its neighbors to satisfy the Threshold value, the filter deletes the spot or line and interpolates between the pixels around the perimeter.
Chapter 10 ✦ Corrective Filtering 483 Figure 10-45: Here you can see the difference between sharpening a digital photograph right off the bat (top) and waiting to sharpen until after you’ve prepared the image with Median, Gaussian Blur, and Unsharp Mask (bottom). But like so many automated tools, this one works only when conditions are favorable. I’m not saying that you shouldn’t ever use it — in fact, you may always want to give this filter the first crack at a dusty image. But if it doesn’t work (as it probably won’t), don’t get your nose out of joint. Just hunker down and eliminate the imperfections manually using the rubber stamp tool, as explained in the “Touching up blemishes” section of Chapter 7.
484 Part III ✦ Selections, Masks, and Filters Now, as I say, Dust & Scratches was designed to get rid of gunk on a dirty scanner. But another problem that the filter may be able to eliminate is moiré patterns. These patterns appear when scanning halftoned images from books and magazines. See, any time you scan a printed image, you’re actually scanning a collection of halftone dots rather than a continuous-tone photograph. In most cases, the halftone pattern clashes with the resolution of the scanned image to produce rhythmic and distracting moirés. Caution When scanning published photographs or artwork, take a moment to find out if what you’re doing is legal. It’s up to you to make sure that the image you scan is no longer protected by copyright — most, but not all, works over 75 years old are considered free game — or that your noncommercial application of the image falls under the fair-use umbrella of commentary or criticism. The Dust & Scratches filter can be pretty useful for eliminating moirés, particularly if you reduce the Threshold value below 40. But this also goes a long way toward eliminating the actual image detail, as shown in Color Plate 10-7. This figure features an image scanned from a previous issue of Macworld magazine. (Because I created the original image, Macworld probably won’t sue me, but you shouldn’t try it.) The left half of Color Plate 10-7 shows the individual color channels in the image; the right half shows the full-color image. I’ve blown up a detail in each image so that you can better see the pixels in the moiré pattern. The top example in the color plate shows the original scanned image with its awful moirés. (Actually, I’ve slightly exaggerated the moirés to account for any printing anomalies; but believe me, with or without enhancement, the image is a mess on screen.) The middle example shows the same image subject to the Dust & Scratches filter with a Radius of 2 and a Threshold value of 20. The moirés are gone, but the edges have all but disappeared as well. I’m tempted to describe this artwork using adjectives such as “soft” and “doughy,” and them are fightin’ words in the world of image editing. But what about that bottom example? How did I manage to eliminate the moirés and preserve the detail that is shown here? Why, by applying the Gaussian Blur, Median, and Unsharp Mask filters to individual color channels. The first step is to examine the channels independently (by pressing Ctrl+1, Ctrl+2, and Ctrl+3). You’ll likely find that each one is affected by the moiré pattern to a dif- ferent extent. In the case of this scan, all three channels need work, but the blue channel — the usual culprit — is the worst. The trick, therefore, is to eliminate the patterns in the blue channel and draw detail from the red and green channels. To fix the blue channel, I applied both the Gaussian Blur and Median commands in fairly hefty doses. I chose Filter ➪ Blur ➪ Gaussian Blur and specified a Radius value of 1.5 pixels, rather high considering that the image measures only about 300 pixels tall. Then I chose Filter ➪ Noise ➪ Median and specified a Radius of 2.
Chapter 10 ✦ Corrective Filtering 485 The result was a thickly modeled image with no moirés but little detail. To firm things up a bit, I chose Filter ➪ Sharpen ➪ Unsharp Mask and entered 200 percent for the Amount option and 1.5 for the Radius. I opted for this Radius value because it matches the Radius that I used to blur the image. When correcting moirés, a Threshold value of 0 is almost always the best choice. A higher Threshold value not only prevents the sharpening of moiré pattern edges but also ignores real edges, which are already fragile enough as it is. The green and red channels required incrementally less attention. After switching to the green channel, I applied the Gaussian Blur filter with a Radius of 1.0. Then I sharpened the image with the Unsharp Mask filter set to 200 percent and a Radius value of 0.5. In the red channel (Ctrl+1), I applied Gaussian Blur with a Radius value of 0.5. The gradual effect wasn’t enough to warrant sharpening. When you’re finished, switch back to the RGB view (Ctrl+0) to see the combined result of your labors. (Or keep an RGB view of the image up on screen by choosing Window ➪ New Window.) The focus of the image will undoubtedly be softer than it was when you started. You can cure this to a limited extent by applying very dis- creet passes of the Unsharp Mask filter, say, with an Amount value of 100 percent and a low Radius value. Keep in mind that oversharpening may bring the patterns back to life or even uncover new ones. Tip One last tip: Always scan halftoned images at the highest resolution available to your scanner. Then resample the scan down to the desired resolution using Image ➪ Image Size, as covered in Chapter 3. This step by itself goes a long way toward eliminating moirés. ✦ ✦ ✦
Full-Court Filtering 11 C H A P T E R ✦ ✦ ✦ ✦ In This Chapter Destructive Filters Capsule descriptions of Photoshop’s special effects filters Corrective filters enable you to eliminate image flaws and apply special effects. Destructive filters, on the other hand, are Clever ways to use the devoted solely to special effects. Even though Photoshop Pixelate filters offers nearly twice as many destructive filters as corrective counterparts, destructive filters are less frequently used and Putting the Mezzotint ultimately less useful. filter to good use Applying the edge- Don’t get me wrong — these filters are a superb bunch. But enhancement filters, because of their more limited appeal, I don’t explain each and including Emboss and every one of them. Rather, I concentrate on the ones that I Find Edges think you’ll use most often, breeze over a handful of others, and let you discover on your own the ones that I ignore. Creating metallic effects with Bas Relief, Photoshop Plastic Wrap, and 6 In addition to explaining the commands found on the Filter menu, this chapter also explains the new Liquify command, Chrome which probably ought to be on the Filter menu but isn’t. Liquify enables you to shove pixels around your image by Exploring new worlds with the help of the dragging them, providing a means for freeform, interactive distortion filters distortion. Tugging at images with the Liquify filter A million wacky effects Designing specialized Oh heck, I guess I can’t just go and ignore half of the com- gradations and other mands on the Filter menu — they’re not completely useless, abstractions after all. It’s just that you aren’t likely to use them more than once every lunar eclipse. So here are the briefest of all pos- Transforming images sible descriptions of these filters: in 3D space Changing a picture’s ✦ Color Halftone: Located under the Filter ➪ Pixelate sub- atmosphere using menu, this command turns an image into a piece of Roy Clouds Lichtenstein artwork, with big, comic-book halftone dots. Although scads of fun, the filter is ultimately a The complete inner novelty that takes about a year and a half to apply. workings of Lighting Effects ✦ ✦ ✦ ✦
488 Part III ✦ Selections, Masks, and Filters ✦ Fragment: Ooh, it’s an earthquake! This lame filter repeats an image four times in a square formation and lowers the opacity of each to create a sort of jiggly effect. You don’t even have any options to control it. It’s quite possible I’m missing the genius behind Filter ➪ Pixelate ➪ Fragment. Then again, maybe not. ✦ Lens Flare: Found in the Render submenu, this filter adds sparkles and halos to an image to suggest light bouncing off the camera lens. Even though pho- tographers work their behinds off trying to make sure that these sorts of reflections don’t occur, you can add them after the fact. You can select from one of three Lens Type options, adjust the Brightness slider between 10 and 300 percent (though somewhere around 100 is bound to deliver the best results), and move the center of the reflection by dragging a point around inside the Flare Center box. Photoshop 6 In addition, you now can Alt-click inside the preview to position the center point numerically. Tip If you want to add a flare to a grayscale image, first convert it to the RGB mode. Then apply the filter and convert the image back to grayscale. The Lens Flare filter is applicable to RGB images only. Here’s another great tip for using Lens Flare. Before choosing the filter, create a new layer, fill it with black, and apply the Screen blend mode (Shift+Alt+S with a non-painting tool selected). Now apply Lens Flare. You get the same effect as you would otherwise, but the effect floats above the background image, protecting your original image from harm. You can even move the lens flare around and vary the Opacity value, giving you more control over the final effect. ✦ Diffuse: Located in the Stylize submenu — as are the three filters that follow — Diffuse dithers the edges of color, much like the Dissolve brush mode dithers the edges of a soft brush. Diffuse is moderately useful but not likely to gain a place among your treasured few. ✦ Solarize: This single-shot command is easily Photoshop’s worst filter. It’s really just a color-correction effect that changes all medium grays in the image to 50 percent gray, all blacks and whites to black, and remaps the other colors to shades in between. (If you’re familiar with the Curves command, the map for Solarize looks like a pyramid.) It really belongs in the Image ➪ Adjust sub- menu or, better yet, on the cutting room floor. ✦ Tiles: This filter breaks an image up into a bunch of regularly sized but ran- domly spaced rectangular tiles. You specify how many tiles fit across the width and height of the image — a value of 10, for example, creates 100 tiles — and the maximum distance each tile can shift. You can fill the gaps between tiles with foreground color, background color, or an inverted or normal version of the original image. A highly intrusive and not particularly stimulating effect. ✦ Extrude: The more capable cousin of the Tiles filter, Extrude breaks an image into tiles and forces them toward the viewer in three-dimensional space. The Pyramid option is a lot of fun, devolving an image into a collection of spikes.
Chapter 11 ✦ Full-Court Filtering 489 When using the Blocks option, you can select a Solid Front Faces option that renders the image as a true 3D mosaic. The Mask Incomplete Blocks option simply leaves the image untouched around the perimeter of the selection where the filter can’t draw complete tiles. Actually, I kind of like Extrude. For the sheer heck of it, Color Plate 11-1 shows an example of Extrude applied to what was once a red rose. I set the Type to Blocks, the Size to 10, the Depth to 30 and Random, with both the Solid Front Faces and Mask Incomplete Blocks radio buttons selected. Pretty great, huh? I only wish that the filter would generate a selection outline around the masked areas of the image so that I could get rid of anything that hadn’t been extruded. It’s a wonderful effect, but it’s not one that lends itself to many occasions. ✦ Diffuse Glow: The first of the Gallery Effects that I mostly ignore, Filter ➪ Distort ➪ Diffuse Glow sprays a coat of dithered, background-colored pixels onto your image. Yowsa, let me at it. ✦ The Artistic filters: As a rule, the effects under the Filter ➪ Artistic submenu add a painterly quality to your image. Colored Pencil, Rough Pastels, and Watercolor are examples of filters that successfully emulate traditional medi- ums. Other filters — Fresco, Smudge Stick, and Palette Knife — couldn’t pass for their intended mediums in a dim room filled with dry ice. ✦ The Brush Strokes filters: I could argue that the Brush Strokes submenu con- tains filters that create strokes of color. This is true of some of the filters — including Angled Strokes, Crosshatch, and Sprayed Strokes. Others — Dark Strokes and Ink Outlines — generally smear colors, while still others — Accented Edges and Sumi-e — belong in the Artistic submenu. Whatever. ✦ The Sketch filters: In Gallery Effects parlance, Sketch means color sucker. Beware, every one of these filters replaces the colors in your image with the current foreground and background colors. If the foreground and background colors are black and white, the Sketch filter results in a grayscale image. Charcoal and Conté Crayon create artistic effects, Bas Relief and Note Paper add texture, and Photocopy and Stamp are stupid effects that you can pro- duce better and with more flexibility using High Pass. Tip To retrieve some of the original colors from your image after applying a Sketch filter, press Ctrl+Shift+F to display the Fade dialog box and try out a few different Mode settings. Overlay and Luminosity are particularly good choices. In Color Plate 11-2, I applied the Charcoal filter with the foreground and background colors set to light blue and dark green. Then I used the Fade command to select the Overlay mode. ✦ The Texture filters: As a group, the commands in the Filter ➪ Texture sub- menu are my favorite effects filters. Craquelure, Mosaic Tiles, and Patchwork apply interesting depth textures to the image. Texturizer provides access to several scalable textures and permits you to load your own (as long as the pattern is saved in the Photoshop format), as demonstrated in Figure 11-1. The one dud is Stained Glass, which creates polygon tiles like Photoshop’s own Crystallize filter, only with black lines around the tiles.
490 Part III ✦ Selections, Masks, and Filters Burlap Canvas Sandstone Random Strokes Figure 11-1: Filter ➪ Texture ➪ Texturizer lets you select from four built-in patterns — including the first three shown here — and load your own. In the last example, I loaded the Random Strokes pattern included with Photoshop. Certainly, there is room for disagreement about which filters are good and which are awful. After I wrote a two-star Macworld review about the first Gallery Effects collection back in 1992 — I must admit, I’ve never been a big fan — a gentleman showed me page after page of excellent artwork he created with them. Recently, a woman showed me her collection of amazing Lens Flare imagery. I mean, here’s a filter that just creates a bunch of bright spots, and yet this talented person was able to go absolutely nuts with it. The moral is that just because I consider a filter or other piece of software to be a squalid pile of unspeakably bad code doesn’t mean that a creative artist can’t come along and put it to remarkable use. But that’s because you are good, not the filter. So if you’re feeling particularly creative today, give the preceding filters a try. Otherwise, skip them with a clear conscience.
Chapter 11 ✦ Full-Court Filtering 491 What about the others? Some filters don’t really belong in either the corrective or destructive camp. Take Filter ➪ Video ➪ NTSC Colors, for example, and Filter ➪ Other ➪ Offset. Both are examples of commands that have no business being under the Filter menu, and both could have been handled much better. 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. The problem with this function is that it’s not an independent color space; it’s a single-shot filter that changes your colors and is done 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 war- rant a second application of the filter. Conversion to NTSC — another light-based system — isn’t as fraught with potential disaster as conversion to CMYK pigments, but it still deserves better treatment than this. The Offset command moves an image a specified number of pixels. Why didn’t I cover it in Chapter 8 with the other movement options? Because the command actually 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 I cover in Chapter 13. You can duplicate an image, offset the entire duplicate by a few pixels, and then mix the duplicate and original to cre- ate highlight or shadow effects. But I much prefer the more interactive control of layering and nudging with the arrow keys. I imagine the Offset filter might find favor with folks who want to automate movements from the Actions palette, but now that Photoshop records movements made with the move tool, I’m not even sure about that. Okay, I admit it; the Offset command is a primitive feature with no purpose in our high-tech modern world. Cross- Among the filters I’ve omitted from this chapter is Filter ➪ Stylize ➪ Wind, which is Reference technically a destructive filter but is covered along with the blur and noise filters in Chapter 10. I discussed Filter ➪ Render ➪ Texture Fill in Chapter 7. And finally, for complete information on the Custom and Displace filters, crack open Chapter A on the CD-ROM at the back of this book. As for the other filters in the Filter ➪ Distort, Pixelate, Render, and Stylize sub- menus, stay tuned to this chapter to discover all the latest and greatest details. Third-party filters In addition to using the filters provided by Photoshop, you can purchase all sorts of plug-in filters from other companies. In fact, Photoshop supports its own flourish- ing cottage industry of third-party solutions from wonderful companies such as Extensis, Alien Skin, Andromeda, and others.
492 Part III ✦ Selections, Masks, and Filters Cross- The CD-ROM at the back of this book includes sample versions of some of my Reference favorite filters. For complete information on the specific filters and the companies that provide them, read the appendix. Many of the filters are demo versions of the shipping products, which means that you can see what they do but you can’t actu- ally apply the effects or they work for only a limited period of time. I know, it’s a drag, but these folks claim that they like to make money every once in a while, and I can’t say that I blame them. One final note about RAM Memory — that is, real RAM — is a precious commodity when applying destructive filters. As I mentioned in Chapter 2, the 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 exclu- sively in memory. If they run out of physical RAM, they choke. Tip Fortunately, there is one potential workaround: When editing a color image, try applying the filter to each of the color channels independently. One color channel requires just a third to a fourth as much RAM as the full-color composite. Sadly, this technique does not help either Lighting Effects or Lens Flare. These delicate flowers of the filter world are compatible only with full-color images; when editing a single channel, they appear dimmed. The Pixelate Filters The Filter ➪ Pixelate submenu features a handful of commands that rearrange your image into clumps of solid color: ✦ Crystallize: This filter organizes an image into irregularly shaped nuggets. You specify the size of the nuggets by entering a value from 3 to 300 pixels in the Cell Size option. ✦ Facet: Facet fuses areas of similarly colored pixels to create a sort of hand- painted effect. ✦ Mosaic: The Mosaic filter blends pixels together into larger squares. You spec- ify the height and width of the squares by entering a value in the Cell Size option box. ✦ Pointillize: This filter is similar to Crystallize, except it separates an image into disconnected nuggets set against the background color. As usual, you specify the size of the nuggets by changing the Cell Size value.
Chapter 11 ✦ Full-Court Filtering 493 The Crystal Halo effect By applying one of the Pixelate filters to a feathered selection, you can create what I call a Crystal Halo effect, named after the Crystallize filter, which tends to deliver the most successful results. (For a preview of these effects, sneak a peek at Figure 11-2.) The following steps explain how to create a Crystal Halo, using the images in Figures 11-2 and 11-3 as an example. STEPS: Creating the Crystal Halo Effect 1. Select the foreground element around which you want to create the halo. Then choose Select ➪ Inverse to deselect the foreground element and select the background. 2. Press Q to switch to the quick mask mode. 3. Choose Filter ➪ Other ➪ Minimum. As I explained in Chapter 10, this filter enables you to increase the size of the deselected area around the foreground element. The size of the Radius value depends on the size of the halo you want to create. I entered 15 because I wanted a 15-pixel halo. (Photoshop 6 no longer limits the Radius value to a measly 10 pixels; you can now enter values as high as 100.) 4. Choose Filter ➪ Blur ➪ Gaussian Blur. Then enter a Radius value 0.1 less than the amount by which you increased the size of the deselected area. In my case, I entered 14.9. This cuts into the image slightly, but hardly enough to be visible, as you can see in the image on the left in Figure 11-2. Figure 11-2: Create a heavily feathered selection outline (left) and then apply the Crystallize filter to refract the feathered edges (right).
494 Part III ✦ Selections, Masks, and Filters 5. Choose Filter ➪ Pixelate ➪ Crystallize. Enter a moderate value in the Cell Size option box. I opted for the value 12, just slightly larger than the default value. After pressing Enter, you get something along the lines of the selection outline shown in the right image in Figure 11-2. The filter refracts the softened edges, as if you were viewing them through textured glass. 6. Switch back to the marching ants mode. Then use the selection as desired. I merely pressed Ctrl+Backspace to fill the selection with white, as shown in the top-left image in Figure 11-3. Crystallize Facet Pointillize Mosaic Figure 11-3: Which aura will Moses don today? The images illustrate the effects of applying each of four filters to a heavily feathered selection in the quick mask mode and pressing Ctrl+Backspace.
Chapter 11 ✦ Full-Court Filtering 495 You may find this technique particularly useful for combining images. You can copy the selection and paste it against a different background or copy a background from a different image and choose Edit ➪ Paste Into to paste it inside the crystal halo’s selection outline. Figure 11-3 shows several variations on the Crystal Halo effect. To create the upper- right image, I substituted Filter ➪ Pixelate ➪ Facet for Filter ➪ Pixelate ➪ Crystallize in Step 5. I also sharpened the result to increase the effect of the filter (which never- theless remains subtle). To create the lower-right image, I applied the Mosaic filter in place of Crystallize, using a Cell Size value of 8. Finally, to create the lower-left image, I applied the Pointillize filter. Because Pointillize creates gaps in a selection, I had to paint inside Moses to fill in the gaps and isolate the halo effect to the back- ground before returning to the marching ants mode. Creating a mezzotint 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 emu- late this effect. Although not entirely successful — true mezzotinting options can be properly implemented only as PostScript printing functions, not as filtering func- tions — they do lend themselves to some pretty interesting interpretations. The filter itself is straightforward. You choose Filter ➪ Pixelate ➪ Mezzotint, select an effect from the Type submenu, and press Enter. A preview box enables you to see what each of the ten Type options looks like. Figure 11-4 shows off four of the effects at 230 ppi. To create Figure 11-5, I applied the Mezzotint filter set to the Long Lines effect. Then I used the Edit ➪ Fade Mezzotint command to mix filtered and original images. I selected Overlay from the Mode pop-up menu and set the Opacity value to 40 per- cent. The result is a scraped image. (I’ve decreased the resolution of the image to 180 ppi so that you can see the effect a little more clearly.) 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 col- ors — black, red, green, blue, yellow, cyan, magenta, and white — in the RGB com- posite view. The upper-left example of Color Plate 11-3 shows an image subject to the Mezzotint filter in the RGB mode. 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 — as shown in the top-middle example of Color Plate 11-3. If you’re looking for bright happy colors, don’t apply Mezzotint in the Lab mode.
496 Part III ✦ Selections, Masks, and Filters Medium dots Coarse dots Short lines Long lines Figure 11-4: The results of applying the Mezzotint filter set to each of four representative effects. These line patterns are on par with the halftoning options offered when you select Mode ➪ Bitmap, as discussed back in Chapter 4.
Chapter 11 ✦ Full-Court Filtering 497 Figure 11-5: To get this effect, I applied the Mezzotint filter and then chose the Fade command (on the Edit menu in Photoshop 6). In the Fade dialog box, I selected the Overlay mode and set the Opacity value to 40 percent. 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, as shown in the top-right example of the color plate, the distribution of the colors is much different. The image appears much lighter and more colorful than its RGB counterpart. This happens because the filter has a lot of black to work with in the RGB mode but very little — just that in the black channel — in the CMYK mode. The bottom row of Color Plate 11-3 shows the effects of the Mezzotint filter after using the Fade command to mix it with the original image. As in Figure 11-4, I chose Overlay from the Mode pop-up menu and set the Opacity value to 40 percent. These three very different images were all created using the same filter set to the same effect. The only difference is color mode.
498 Part III ✦ Selections, Masks, and Filters Edge-Enhancement Filters The Filter ➪ Stylize submenu offers access to a triad of filters that enhance the edges in an image. The most popular of these is undoubtedly Emboss, which adds dimension to an image by making it look as if it were carved in relief. The other two, Find Edges and Trace Contour, are less commonly applied but every bit as capable and deserving of your attention. Embossing an image The Emboss filter works by searching for high-contrast edges (just like the Sharpen Edge 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 ➪ Stylize ➪ Emboss, Photoshop displays the Emboss dialog box shown in Figure 11-6. The dialog box offers three options: ✦ Angle: The value in this option box determines the angle at which Photoshop lights the image in relief. For example, if you enter a value of 90 degrees, you light the relief from the bottom straight upward. The white pixels therefore appear on the bottom sides of the edges, and the black pixels appear on the top sides. Figure 11-7 shows eight reliefs lit from different angles. I positioned the images so that they appear lit from a single source. Figure 11-6: The Emboss dialog box lets you control the depth of the filtered image and the angle from which it is lit.