Photoshop cs5 cho nhiếp ảnh gia part 31 ppsx

186 c h a p t e r 4: FOUNDATIONS ■ The tablet icon is for graphics-tablet users only. Clicking it overrides any other settings for the pen and causes pen pressure to alter brush size. We do not find this helpful for most photographic work. You’re just about ready to take the Brush tool for a test-drive, but you still need to adjust the size of the brush. Place the cursor on the new document you created, and evaluate the size of the brush. Then, press the left and right square bracket keys ([ and ]) to reduce or enlarge the size of the brush, respectively. You can hold down the Shift key while pressing the right and left bracket keys to adjust the hardness/softness, respectively, of the brush, but this isn’t quite as visual as the size adjustment. For that reason we usually set the hardness/softness directly in the Brush panel. CS5 also gives you the option to drag and modify the brush tip. To resize the brush tip in Windows, press Alt and right-click while dragging the cursor. On a Mac, press Option+Ctrl and drag. To modify the softness/hardness of the brush in Win- dows, press Alt+Ctrl and right-click while dragging. Unfortunately there does not seem to be a comparable Mac shortcut. Note: To draw a horizontal or perpendicular straight line, hold down the Shift key and then click and drag the cursor. Note: The Caps Lock key toggles the mouse-pointer display between Precise and the brush size settings. If you’re not able to see the circle that defines the shape of your brush, check the status of Caps Lock. This is one of the most common problems we encounter in workshops! Brush Panel The Brush panel is located on the tool Options bar when you select a Brush tool, and is accessible as a panel as well. Clicking the icon opens the Brush panel in a float- ing dialog box. You can select preset brushes and set the same parameters you set in the Brush Preset Picker on the Options bar, but in addition you can modify brush tip options. Most of these options are more useful to graphic artists than to nature pho- tographers, but if you use a graphics tablet such as a Wacom, you’ll need to use this dialog box to set the brush so that the opacity of your stroke varies with pen pressure. This will be useful when you’re painting on layer masks. (We’ll be doing that exten- sively in later chapters.) To vary the opacity of your brush stroke according to the pressure applied with your stylus, follow these steps: 1. Attach the graphics tablet and install any necessary software. 2. Select the Brush tool. 3. Click the Brush panel or choose Window > Brush. 607343c04.indd 186 4/11/10 11:04:37 PM 187 ■ BRUSH TOOLS 4. Select Transfer. Then choose Pen Pressure from the Controls menu under the Opacity Jitter slider control, as shown in Figure 4.42. Figure 4.42 Setting Pen Pressure to control opacity is extremely useful when painting on a layer mask using a graphics tablet. For Photoshop Elements Users: Setting Brush Options The Elements Brush drop-down list is simpler than the one in CS5, having no options for Master Diameter or Hardness. To see a stroke preview, like in the Photoshop Brush drop-down, click on the More Options button and select Stroke Thumbnail. Although Elements does not have a Brush panel, if you click the Brush icon grouped with the tool options, to the right of the Airbrush Button, Elements will open the Options panel seen in the following image. Here, in addition to Hardness and Spacing, there are controls for the following: Fade: How quickly the paint fades away as you paint (similar to lifting a brush up off of a phys - ical canvas while drawing a stroke). Lower values mean the color fades away faster, although a value of 0 means to turn fade off. Hue Jitter: How often the brush color changes from the foreground to background color (not very useful for photographers). Continues 607343c04.indd 187 4/11/10 11:04:37 PM 188 c h ap ter 4: FO U NDAT IONS ■ For Photoshop Elements Users: Setting Brush Options (Continued) Scatter: How much the brush “skips” off the page when you draw. Spacing: Determines whether the brush stroke appears to be continuous or to be made of indi- vidual “dots” of paint. Hardness: How discrete the edges are as you paint. If you are using a tablet, clicking the small triangle grouped with the other tool options, between the Airbrush and Brush Options buttons, will bring up a panel that allows you to choose which brush options are affected by pen pressure. We recommend leaving this at the default, Size. Try It! Now comes the fun part. You have an empty canvas before you, and you know how to adjust the behavior of the Brush tool. So, start painting away! Get comfortable working with the Brush tool, using the mouse (or a stylus) to paint strokes on the canvas. Be sure to adjust all the various set- tings for the Brush tool, including the Color, Hardness, Opacity, and the size of the brush so you get comfortable adjusting the various parameters. You can then use the Brush tool with confidence in the wide variety of situations we’ll describe in later chapters. The Color Replacement Tool The Color Replacement tool (Figure 4.43) is a specialized Brush tool with properties that allow you to alter the color of specific areas within your image. It produces simi- lar behavior in most cases to what you could achieve with the Brush tool in conjunc- tion with specific settings, but it provides extended capability above and beyond the Brush. The Color Replacement tool is useful for fixing small areas of color problems within an image, where you need to change the color without changing the tonality or texture of the area. Figure 4.43 The Color Replacement tool lives under the Brush tool. For this type of use, we typically work with the Color Replacement tool with the following options set: Mode set to Color, so we’re changing the color in the image. Sampling set to Continuous (the first of the three option buttons), which causes the tool to change color anywhere we paint, not just based on an initial sampling point, for example. Occasionally we use the second button, Sampling Once , to replace just a certain color. Limits set to Contiguous, to adjust only those colors that are contiguous to those we paint over. 607343c04.indd 188 4/11/10 11:04:38 PM 189 ■ BRUSH TOOLS Tolerance at 100%, so all areas we paint on are adjusted. Anti-Alias checked. When you paint with the Color Replacement tool with the settings recom- mended here, it changes the color of the pixels under the brush, preserving tonality and texture. For example, if you have some color contamination on a flower because a flower of a different color was very close to the lens and resulted in a wash of color that is completely out of focus, you could use this tool to paint an appropriate color to fix the flower. Painting with a neutral color (such as black) changes the color to a shade of gray. If you want to paint a color correction, you naturally need to find an appropri- ate color to paint with using the Color Replacement tool. To do so, simply hold the Alt/Option key, and click an appropriate color within the image to make that color the foreground color. You can then paint with that color in appropriate areas of the image using the Color Replacement tool to change the color as needed. Try It! To practice using the Color Replacement tool, open the image ColorReplacement on www. sybex.com/go/photoshopnature , select the Color Replacement tool, set the foreground color to a muted orange, and paint on the red flower on the left to change its color. Be careful to paint only the red flower, zooming in and using a small brush as needed when painting near the foreground flower. The History Brush The History Brush tool is unique—it allows you to selectively paint certain areas of your image to take them “back in time,” reflecting what they looked like before cer- tain tasks were performed. This allows you to perform actions on the entire image and then undo those actions in specific areas as desired. Let’s look at an example to help you understand this concept. Note: Neither of us uses the History Brush often, preferring to use various layers and masks to produce the same results. However, it can come in handy, so we present it here as an option. Start by opening an image and applying an artistic filter to that image. For example, you might select Filter > Artistic > Colored Pencil, adjust the settings for this filter, and click OK. Then select the History Brush from the Tools panel. (You can also access it by pressing Y on your keyboard.) By default, when you paint with the History Brush, it changes the areas you paint on to what they looked like when you first opened the image. However, you can change the source for the History Brush to any history state on the History panel. To do so, click the box to the left of the name of the history state (which defines the action performed at that step) on the History panel. This places a small History Brush icon in that box, as shown in Figure 4.44, so you know it is the source for this tool. 607343c04.indd 189 4/11/10 11:04:38 PM 190 c h a p t e r 4: FOUNDATIONS ■ Figure 4.44 On the History panel, click the box to the left of the state you want to paint back to, dening the source for the History Brush tool. For example, in your new, blank practice document, you’ve only opened an image and applied the Colored Pencil filter to it, so you don’t have many options. However, in Figure 4.45 we changed the image from a 16-bit image to an 8-bit image in order to use the Artistic filters, so we set the History Brush to use the 8-bit his- tory state. You can set the source to any step in the history using the same bit depth and crop to specifically select that history state as the definition of how you want to change the pixels. Figure 4.45 With the History Brush, you can selectively paint areas back to the way they looked before you made a particular adjustment. Ph ot o by EllEn An on With the source set, you’re ready to paint. Note that you have the same options on the Options bar for the History Brush as you do for the regular Brush tool. In most cases, you want to use a soft-edged brush of an appropriate size, the Normal blend- ing mode, and a 100% opacity. Wherever you paint, the effect of the Colored Pencil filter in this example is removed, returning those areas of the image to their original appearance, as shown in Figure 4.45. However, at times you might want to paint at a reduced Opacity setting—for example, when you want to “tone down” an adjustment in certain areas of the image rather than eliminate the effect altogether. 607343c04.indd 190 4/11/10 11:04:38 PM 191 ■ BRUSH TOOLS Think of the History Brush as a “selective undo” tool. Anytime you’ve changed pixel values in an image and want to reduce or eliminate the effect in certain areas, this tool allows you to do exactly that with very good control. However, if you have made certain types of changes to your image, such as cropping it or changing the bit depth, you’ll need to change the source to a state that reflects the same conditions, rather than setting it to the initial image. Otherwise, the tool refuses to work. 607343c04.indd 191 4/11/10 11:04:38 PM 5 Ph ot o by EllEn An on 607343c05.indd 192 4/13/10 2:44:05 PM . the Brush tool. 3. Click the Brush panel or choose Window > Brush. 607343c04.indd 186 4/11/10 11:04:37 PM 187 ■ BRUSH TOOLS 4. Select Transfer. Then choose Pen Pressure from the Controls menu. a layer mask using a graphics tablet. For Photoshop Elements Users: Setting Brush Options The Elements Brush drop-down list is simpler than the one in CS5, having no options for Master Diameter. up a panel that allows you to choose which brush options are affected by pen pressure. We recommend leaving this at the default, Size. Try It! Now comes the fun part. You have an empty canvas