adobe photoshop 6 bible phần 3 potx

177 Chapter 4 ✦ Defining Colors STEPS: Using the Multichannel Mode as an Intermediary Step 1. Open an RGB image. If the image is already open, make sure that it is saved to disk. 2. Choose Image ➪ Mode➪ Multichannel. This eliminates any relationship between the formerly red, green, and blue color channels. 3. Click the new channel icon at the bottom of the Channels palette. Or choose the New Channel command from the palette menu and press Return to accept the default settings. Either way, you add a mask channel to the image. This empty channel will serve as the black channel in the CMYK image. (Photo- shop won’t let you convert from the multichannel mode to CMYK with less than four channels.) 4. Press Ctrl+I. Unfortunately, the new channel comes up black, which would make the entire image black. To change it to white, press Ctrl+I or choose Image ➪ Adjust ➪ Invert. 5. Choose Image ➪ Mode➪ CMYK. The image looks washed out and a tad bit dark compared to its original RGB counterpart, but the overall color scheme of the image remains more or less intact. This is because the red, green, and blue color channels each have a respective opposite in the cyan, magenta, and yellow channels. 6. Press Ctrl+Shift+L. Or choose Image ➪ Adjust➪ Auto Levels. This punches up the color a bit by automatically correcting the brightness and contrast. 7. Convert the image to RGB, and then back to CMYK again. The problem with the image is that it lacks any information in the black channel. So although it may look okay on-screen, it will lose much of its definition when printed. To fill in the black channel, choose Image ➪ Mode ➪ RGB Color, and then choose Image ➪ Mode ➪ CMYK Color. Photoshop automatically generates an image in the black channel in keeping with the standards of color separations (as explained in Chapter 18). Keep in mind that these steps are by no means a recommended procedure for con- verting an RGB image to a CMYK image. Rather, they are merely intended to suggest one way to experiment with channel conversions to create a halfway decent image. You can likewise experiment with converting between the Lab, multichannel, and RGB modes, or Lab, multichannel, and CMYK. Replacing and swapping color channels If you truly want to abuse the colors in an RGB or CMYK image, there’s nothing like replacing one color channel with another to produce spectacular effects. Color Plate 4-4 shows a few examples applied to an RGB image. 178 Part II ✦ Painting and Retouching ✦ In the first example, I used the Channel Mixer to replace the red channel with the blue. I did this by setting the Output Channel to Red, changing the Red value to 0 percent and the Blue value to 100 percent. The result is a green woman floating in a green sea under a purple sky. ✦ To achieve the next example, I again started from the original RGB image and used Channel Mixer to replace the green channel with the red. The result this time is a yellow woman against a deep blue background. ✦ To create the purple woman in a green world on the right side of Color Plate 4-4, I replaced the blue channel with the red. You can create more interesting effects by using Color Mixer to swap the contents of color channels. For example, in the lower left example of Color Plate 4-4, I swapped the contents of the red and blue channels to create a blue woman on a green sea under an orange sky. To accomplish this, I set the Output Channel to Red, set the Red value to 0 and the Blue to 100. Then I switched to the Blue channel (Ctrl+3) and set the Red value to 100 and the Blue to 0. The next two examples along the bottom of Color Plate 4-4 show the results of swapping the red and green channels (for a bright green woman) and the green and blue channels. Because the green and blue channels contain relatively similar data, this produces the subtlest effect, chiefly switching the sea and sky colors and turn- ing the swimsuit pink. ✦✦✦ Painting and Editing Paint and Edit Tool Basics Here it is, Chapter 5, and I’m finally getting around to explain- ing how to use Photoshop’s painting tools. You must feel like you’re attending some kind of martial arts ritual where you have to learn to run away, cry, beg, and attempt bribery before you get to start karate-chopping bricks and kicking your instructor. “The wise person journeys through the funda- mentals of image editing before painting a single brushstroke, Grasshoppa.” Wang, wang, wang. (That’s a musical embellish- ment, in case you didn’t recognize it. Man, I hate to have to explain my jokes. Especially when they’re so measly.) Now that you’ve earned your first belt or tassel or scouting patch or whatever it is you’re supposed to receive for slogging this far through the book, you’re as prepared as you’ll ever be to dive into the world of painting and retouching images. You might think these tools require artistic talent. In truth, each tool provides options for almost any level of proficiency or experience. Photoshop offers get-by measures for novices who want to make a quick edit and put the tool down before they make a mess of things. If you have a few hours of experi- ence with other painting programs, you’ll find Photoshop’s tools provide at least as much functionality and, in many cases, more. (The one exception is Painter, which is several times more capable than Photoshop in the painting department.) And if you’re a professional artist —well, come on now —you’ll have no problems learning how to make Photoshop sing. No matter who you are, you’ll find electronic painting and editing tools more flexible, less messy, and more forgiving than their traditional counterparts. 5 5 CHAPTER ✦✦✦✦ In This Chapter Exploring Photoshop’s paint and edit tools Painting straight and perpendicular lines Smudging colors Adjusting saturation and contrast with the sponge tool Selecting brushes and tool options from the Options bar Saving and editing custom brush sets in the Preset Manager Creating lines that fade away or taper to a point Working with pressure-sensitive drawing tablets Selecting brush modes from the keyboard ✦✦✦✦ 180 Part II ✦ Painting and Retouching If you screw something up in the course of painting your image, stop and choose Edit ➪ Undo (or press Ctrl+Z). If this doesn’t work, press Ctrl+Alt+Z to step back through your paint strokes. (These shortcuts assume that you haven’t changed the default Redo Key setting in the Preferences dialog box; see Chapter 2 for more infor- mation.) You also can select a previous state in the History palette, as explained in Chapter 7. The History palette lists brushstrokes and other changes according to the tool you used to create them. Meet your tools Photoshop provides three paint tools: pencil, paintbrush, and airbrush. You also get six edit tools: smudge, blur, sharpen, burn, dodge, and sponge. Figure 5-1 shows all the tools along with the keyboard shortcuts for selecting them. Figure 5-1: The three paint tools and six edit tools; note that the pencil and paintbrush now share a toolbox slot and a keyboard shortcut. Cross- Reference 181 Chapter 5 ✦ Painting and Editing When two or more tools share a slot in the toolbox, click or drag on the arrow in the lower corner of the tool icon to display a flyout menu of all the tools, as shown in Figure 5-1. Or you can just press the keyboard shortcut listed in the menu to cycle through the tools. However, if you turn on the Use Shift Key for Tool Switch option in the General panel of the Preferences dialog box (Ctrl+K), you must press Shift and the shortcut to switch tools. You can vary the performance of the paint and edit tools by using the controls on the new Options bar, which contains tool settings formerly accessed through the Options palette and the Brushes palette. If you don’t see the Options bar, shown in Figure 5-2, double-click any tool icon or just press Enter to display it. You also can choose Windows➪ Show Options. If you want to keep other palettes close by, you can dock them in the Options bar, which appears if you set your monitor’s screen resolution to display more than 800 pixels horizontally. Just drag the palette tab to the docking well, labeled in Figure 5-2. Upcoming sections in this chapter explain all the ways to adjust the paint and edit tools. Check out Chapter 2 for more details about the Options bar. If you want to return a tool to its default settings, click the tool’s icon at the left end of the Options bar and choose Reset Tool from the pop-up menu. Click Reset All Tools to return every tool back to its original state. Figure 5-2: Tool settings formerly contained in the Options and Brushes palettes now hang out in the Options bar. In addition to the paint and edit tools, Photoshop 6 provides a set of tools for drawing vector objects. I cover these tools in Chapter 14. Cross- Reference Reset tool(s) Options bar Docking wellDocked palette 6 Photoshop 6 6 Photoshop 6 182 Part II ✦ Painting and Retouching The paint tools The paint tools apply paint in the foreground color. In this and other respects, they work like their counterparts in other painting programs, but there are a few exceptions: ✦ Pencil: Unlike pencil tools found in most other painting programs — which paint lines 1 pixel thick —Photoshop’s pencil paints a hard-edged line of any thickness you specify. Figure 5-3 compares the default 1-pixel pencil line with a fatter pencil line, a paintbrush line, and an airbrush line. If you’re used to selecting the pencil tool by pressing P (as in Photoshop 3), Y (as in Version 4), or N (as in Version 5), prepare for yet another change. The new pencil tool shortcut is B, same as for the paintbrush. Toggle back and forth between the two tools by pressing B repeatedly (or Shift+B, depending on your Preferences setting for keyboard tool switches). Figure 5-3: Five lines painted in black with the pencil, paintbrush, and airbrush tools. The Wet Edges option (second from right) causes the line to appear translucent. I held the airbrush tool in place for a few moments at the end of the line located at the far right. ✦ Paintbrush: The paintbrush works like the pencil tool, except it paints an antialiased (softened) line that blends in with its background. Thin pencil line Thick pencil line Paintbrush line Paintbrush with wet edges Airbrush line 6 Photoshop 6 183 Chapter 5 ✦ Painting and Editing When you select the Wet Edges check box on the Options bar, the paintbrush creates a translucent line with darkened edges, much as if you were painting with watercolors. Soft brush shapes produce more naturalistic effects. Figure 5-3 shows an example of this effect. ✦ Airbrush: Dismissing Photoshop’s airbrush tool as a softer version of the paintbrush is tempting because it uses a softer brush shape by default. Photoshop’s default airbrush settings also call for a lighter pressure, so the airbrush paints a translucent line. But unlike the paintbrush, which applies a continuous stream of color and stops applying paint when you stop dragging, the airbrush applies a series of colored dollops and continues to apply these dollops as long as you press the mouse button. Figure 5-3 shows the dark glob of paint that results from pressing the mouse button while holding the mouse motionless at the end of the drag. The edit tools The edit tools don’t apply color; rather, they influence existing colors in an image. Figure 5-4 shows each of the six edit tools applied to a randomized background. Future sections cover the tools in more detail, but here’s a brief introduction: ✦ Blur: The first of the two focus tools, the blur tool blurs an image by lessening the amount of color contrast between neighboring pixels. ✦ Sharpen: The second focus tool selectively sharpens by increasing the contrast between neighboring pixels. Generally speaking, both the blur and sharpen tools are less useful than their command counterparts in the Filters menu. They provide less control and usually require scrubbing at an image. Maybe I’ve been using a computer too long, but my wrist starts to ache when I use these tools. If, unlike me, you like the basic principle behind the tools, but you want to avoid carpal tunnel syndrome, you can achieve consistent, predictable results with- out scrubbing by using the tools in combination with the Shift key, as described in the next section, “Basic techniques.” ✦ Smudge: The smudge tool smears colors in an image. The effect is much like dragging your finger across wet paint. ✦ Dodge: The first of three toning tools, the dodge tool lets you lighten a portion of an image by dragging across it. Named after a traditional film exposure tech- nique, the dodge tool is supposed to look like a little paddle thingie —you know, like one of those spoons you put over your eye at the optometrist’s— that you wave over photographic paper to cast a shadow and thereby lighten the exposure. Thank golly we no longer have to wave little paddle thingies in our modern age. ✦ Burn: The burn tool lets you darken a portion of an image by dragging over it. The effect is similar to burning a film negative, which you apparently do by holding your hand in a kind of O shape in an effort to focus the light, kind of like frying a worker ant using a magnifying glass (except not quite so smelly). At least, that’s what they tell me. Sadly, I’ve never had the pleasure of trying it. 184 Part II ✦ Painting and Retouching Figure 5-4: Dragging with Photoshop’s edit tools creates these effects. The boundaries of each line are highlighted so that you can clearly see the distinctions between line and background. If you’re like most folks, you have difficulty remembering which tool lightens and which one darkens. So here’s a little tip: That little hand icon looks like it could be holding a piece of toast, and when you burn toast, it gets darker. Hand, toast, burn, darker. That other tool, the eye doctor paddle, is not hold- ing toast, so it must lighten. You’ll never have problems again. ✦ Sponge: The final toning tool, the sponge tool, robs an image of both saturation and contrast. Or you can set the tool so it boosts saturation and adds contrast. For more information, stay tuned for the upcoming section “Mopping up with the sponge tool.” To access the sharpen tool temporarily when the blur tool is selected, press and hold Alt while using the tool. The sharpen tool remains available only as long as you press Alt. You also can press Alt to access the blur tool when the sharpen tool is selected, to access the burn tool when the dodge tool is selected, and to access the dodge tool when the burn tool is selected. (If the sponge tool is active, pressing Alt has no effect, except maybe to give your finger a cramp.) Tip Blur Sharpen Smudge Dodge Burn Sponge 185 Chapter 5 ✦ Painting and Editing You can replace the blur tool with the sharpen tool in the toolbox by Alt-clicking on the tool’s icon. Alt-click again to select the smudge tool and yet again to cycle back to the blur tool. Likewise, you can Alt-click the dodge tool icon to cycle between the dodge, burn, and sponge tools. As explained in Chapter 2, the keyboard shortcuts also toggle between the tools. When the blur tool is selected, press R to switch to the sharpen tool. Repeated press- ings of R take you to the smudge tool and back to the blur tool. When the dodge tool is selected, press O to toggle to the burn tool; press O again to get the sponge. If these shortcuts don’t work for you, head for the General panel of the Preferences dialog box (Ctrl+K). Chances are, the Use Shift for Tool Switch check box is selected, which means that you have to press Shift plus the keyboard shortcut to cycle through tools. Turn the check box off to give your Shift finger a rest. Basic techniques I know several people who claim that they can’t paint, and yet they create beautiful work in Photoshop. Even though they don’t have sufficient hand-eye coordination to write their names on screen, they have unique and powerful artistic sensibilities, and they know many tricks that enable them to make judicious use of the paint and edit tools. I can’t help you in the sensibilities department, but I can show you a few tricks to boost your ability and inclination to use the paint and edit tools. Painting a straight line You probably already know that you can draw a straight line with the line tool. And you may be wondering why I don’t include the line tool in my discussion of painting tools. Well, the reason is that as a painting tool, the line tool is pretty limited in its usefulness. In the line tool’s defense, it has evolved in Version 6. You now can draw either vector lines or raster lines using the tool, and you also can set the tool to create a work path. You set the tool’s function through the trio of icons on the left end of the Options bar. Click the first button to create a vector shape on a new layer, as discussed in Chapter 14; click the middle button to create a work path, a topic I cover in Chapter 9; and click the third button to paint a regular, pixel-based line. About the only reason I ever use the line tool in painting mode is to create arrows. (I explain how in the “Applying Strokes and Arrowheads” section of Chapter 8.) If you don’t want arrows, you’re better off using Photoshop’s other means for creat- ing straight lines: the Shift key. Using this method, you can paint with different brushes and access other options not available when you work with the line tool. 6 Photoshop 6 6 Photoshop 6 Tip 186 Part II ✦ Painting and Retouching To paint a straight line with any of the paint tools, click at one point in the image and then press Shift and click at another point. Photoshop connects the start and end points with a straight stroke of paint. Use this same technique to apply an edit tool in a straight line. To create free-form polygons, continue to Shift-click with the tool. Figure 5-5 fea- tures a photograph and a tracing I made on a separate layer (covered in Chapter 12) exclusively by Shift-clicking with the paintbrush tool. As an academic exercise, I never dragged with the tool, I never altered the brush size, and I used just two colors: black and gray. Figure 5-5: Starting from an image by photographer Barbara Penoyar (left), I created a stylized tracing (right) by clicking and Shift-clicking with the paintbrush tool on a separate layer. The Shift key makes the blur and sharpen tools halfway useful. Suppose that you want to edit the perimeter of the car shown in Figure 5-6. The arrows in the figure illustrate the path your Shift-clicks should follow. Figure 5-7 shows the effect of Shift-clicking with the blur tool; Figure 5-8 demonstrates the effect of Shift-clicking with the sharpen tool. Tip [...]... 120 pixels 132 pixels 150 pixels 166 pixels ✦ Spacing: The Spacing option controls how frequently a tool affects an image as you drag, measured as a percentage of the brush shape Suppose the Diameter of a brush shape is 12 pixels and the Spacing is set to 25 percent (the setting for all default brush shapes) For every 3 pixels (25 percent of 12 pixels) you drag with the paintbrush tool, Photoshop lays... the number keys and you’ll thank yourself later Photoshop Brush Dynamics 6 In previous versions of Photoshop, you’ve been able to apply paint and edit effects in strokes that varied in size, opacity, pressure, or color along the length of your drag But to take advantage of some of these options, you needed a pressure-sensitive drawing tablet Photoshop 6 enables mouse users to enjoy the same flexibility... Painting with the smudge tool Photoshop Many first-time Photoshop artists misuse the smudge tool to soften color transitions In fact, softening is the purpose of the blur tool The smudge tool smears colors by shoving them into each other The process bears more resemblance to the finger painting you did in grade school than to any traditional photographicediting technique 6 In Photoshop, the performance... brush as follows: Photoshop ✦ Brush options: After you press Enter, Photoshop displays a variation of the New Brush dialog box You can change the spacing of the brush shape and specify whether Photoshop antialiases the edges or leaves them as is If the brush is sufficiently large, the Anti-aliased check box appears dimmed All custom brushes are hard-edged when you use the pencil tool 6 When you display... folder in the main Photoshop folder Brush sets have the file extension abr You also can create your own custom brush collections This option comes in handy if you need to share custom brushes with a fellow Photoshop user Just create a new brush set containing your custom brushes and then give your colleague the brush set file (Note that earlier versions of Photoshop can’t load Version 6 brush presets.)... dropdown palette, you make the job of hunting down the brush you want easier 6 You can save brush sets — as well as load and edit them — either by choosing commands on the palette menu in the Brush drop-down palette (see Figure 5- 16, earlier in this chapter) or via the Brushes panel of the Preset Manager dialog box, new to Photoshop 6 To check out the dialog box, choose Edit ➪ Preset Manager Figure 5-25... see the proliferation of face details mixed into the eyes in the right example Meanwhile, the face layer remains absolutely unaffected 1 93 194 Part II ✦ Painting and Retouching Photoshop Figure 5-14: The eyes layer from the previous figure shown by itself 6 In Version 6, you can further vary the smudge tool effects through the Brush and Brush Dynamics palettes The upcoming section “Brush Shape and Opacity”... computer graphics Chapter 5 ✦ Painting and Editing Photoshop Exploring the Brush Dynamics palette 6 The Brush Dynamics drop-down palette, shown in Figure 5- 26, holds the secret to plying the paint and edit tools in strokes that vary from one end to the other Click the brush icon at the right end of the Options bar to display the palette Figure 5- 26: Click the brush icon to display the Brush Dynamics... inspire your own investigation of these options Photoshop Fading the paint (and other effects) 6 In earlier versions of Photoshop, you could create a fading paint stroke by selecting the Fade check box in the Options palette and then specifying whether you wanted the stroke to fade from the foreground color to the background color or to transparency In Version 6, you have the same choices, but they’re handled... Fade value to 60 and drew each of the four perpendicular lines with the paintbrush tool I changed the value to 36 before drawing the four 45-degree diagonal lines The eight very short lines that occur between the perpendicular and diagonal lines were drawn with a Fade value of 20, and I created the larger sparkle on the left by periodically adjusting the Fade value, this time from 90 to 60 to 42 Figure . tools, Photoshop 6 provides a set of tools for drawing vector objects. I cover these tools in Chapter 14. Cross- Reference Reset tool(s) Options bar Docking wellDocked palette 6 Photoshop 6 6 Photoshop 6 182 Part. different brushes and access other options not available when you work with the line tool. 6 Photoshop 6 6 Photoshop 6 Tip 1 86 Part II ✦ Painting and Retouching To paint a straight line with any of the paint. background. Thin pencil line Thick pencil line Paintbrush line Paintbrush with wet edges Airbrush line 6 Photoshop 6 1 83 Chapter 5 ✦ Painting and Editing When you select the Wet Edges check box on the Options