Chapter 11: Distortions and Effects - Photoshop.CS.Bible [Electronic resources] نسخه متنی

Chapter 11: Distortions and Effects

Destructive Filters

Corrective filters enable you to eliminate image flaws and apply special effects. Destructive filters, on the other hand, are devoted solely to special effects. Even though Photoshop offers nearly twice as many destructive filters as corrective counterparts, destructive filters are less frequently used and ultimately less useful.

Don't get me wrong — these filters are a superb bunch. But because of their more limited appeal, I don't explain each and every one of them. Rather, I concentrate on the ones that I think you'll use most often, breeze over a handful of others, and let you discover on your own the ones that I ignore.

A million wacky effects

Oh heck, I guess I can't just go and ignore half of the commands on the Filter menu — they're not completely useless, 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 possible descriptions of these 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 photographers 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 between 100 and 150 is bound to deliver the best results), and move the center of the reflection by dragging a point around inside the Flare Center box. In addition, you can Alt-click (Win) or Option-click (Mac) inside the preview to position the center point numerically. By way of example, Figure 11-1 shows the effects of the three different Lens Type settings; in each case the Brightness value was set to 140 percent.

Figure 11-1: Starting with a very dark image, I applied the different Lens Type settings available in the Lens Flare filter.

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 only to RGB images.

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 by pressing Shift+Alt+S (Shift-Option-S on the Mac) with a nonpainting 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. Frankly, I've grown more and more fond of Lens Flare over time — it's also a flexible tool for making specular highlights.

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. Even with the Anisotropic mode, which tends to create the least change in an image's colors, Diffuse is not likely to gain a place among your most treasured filters.

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, changes 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 Adjustments submenu or, better yet, on the cutting room floor.

Tiles: This filter does its best to break an image up into a bunch of square, randomly spaced rectangular tiles. You specify how many tiles fit across the smaller of the image's width or height — a value of 10, for example, creates 100 tiles in a perfectly square image — and the maximum distance each tile can shift. You can fill the gaps between tiles with the foreground color, the 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. When using the Blocks option, you can select a Solid Front Faces option that renders the image as a true 3-D 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, Figure 11-2 shows two examples of Extrude applied to what was once a statue. In the middle image, I set the Type to Blocks, the Size to 6, the Depth to 30 and Random, with the Solid Front Faces radio button selected. The example on the right shows the Pyramid option, with Size at 10 and Depth at 20. 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.

Figure 11-2: Two examples of the fun Extrude filter, which can turn the most dignified image into one of those toys with hundreds of thin metal rods which you can press your face into to create an impression. (What the heck are those things called, anyway?)

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.

Custom: The first of two custom effects filters in Photoshop, Filter Other Custom enables you to design your own convolution kernel, a variety of filter in which neighboring pixels get mixed together. The kernel can be a variation on sharpening, blurring, embossing, or a half-dozen other effects. You create your filter by entering numerical values in a matrix of options.

Displace: Located in the Distort submenu, Displace is Photoshop's second custom effects filter. It permits you to distort and add texture to an image by moving the colors of certain pixels in a selection. You specify the direction and distance that the Displace filter moves colors by creating a second image called a displacement map, or dmap (pronounced dee-map) for short. The brightness values in the displacement map tell Photoshop which pixels to affect and how far to move the colors of those pixels.

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 mediums. Other filters — Fresco, Palette Knife, and Smudge Stick — 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 contains 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, most of these filters replace 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 Cont Crayon create artistic effects, Bas Relief and Note Paper add texture, and Photocopy and Stamp are stupid effects that you can produce better and with more flexibility using High Pass.

The Texture filters: As a group, the commands in the Filter Texture submenu are my favorite effects filters. Craquelure, Mosaic Tiles, and Patchwork apply interesting depth textures to an 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 11-3. The one semidud Texture filter is Stained Glass, which creates polygon tiles like Photoshop's own Crystallize filter, only with black lines around the tiles.

Figure 11-3: 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 Water.psd pattern located at Adobe Photoshop CS/ Presets/Patterns/Adobe ImageReady Only.

Photoshop 3D Transform and Texture Fill: Age-old, venerable, and largely useless, these two remnants of a bygone era are conspicuous in their absence with the release of Photoshop CS. For those inclined to stay up nights checking the phone every fifteen minutes and hoping against hope that these filters are okay, don't fret: The filters are indeed safe and warm. Adobe has simply decided that they're arcane, so they don't install automatically with the program. They're on the Photoshop CD, and you'll need to install them manually to access them. See, all that worrying was for naught. I think we can all let out a collective "Huzzah!" now that the 3D Transform and Texture Fill mystery has finally been solved.

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 the filters. More recently, a woman showed me her collection of amazing Lens Flare imagery. I mean, here's a filter that basically 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.

What about the others?

Some filters don't 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 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 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 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 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. But I much prefer the more interactive control of layering and nudging with the arrow keys.

As for the other filters in the Filter Distort, Pixelate, Render, and Stylize submenus, stay tuned to this chapter to discover all the latest and greatest details.

One final note about RAM

Memory — that is, real RAM — is a precious commodity when applying destructive filters. As I 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 choke.