Photoshop cs5 cho nhiếp ảnh gia part 43 pptx

263 ■ CREATING A VIRTUAL SPLIT NEUTRAL-DENSITY FILTER Try It! To start getting more comfortable with Curves, open the image Curves at www.sybex .com/go/photoshopnature and make some adjustments, starting with a simple S curve adjust- ment and then working to fine-tune the overall tonality to your liking. Creating a Virtual Split Neutral-Density Filter Another tool that you can use to create a layer mask is the Gradient tool. This allows you to place a gradient on the mask, resulting in an adjustment that affects one side of the image completely but gradually tapers off in a given direction until it has no effect at the other side of the image. The most common example of using such a gradient is in a composition where you would otherwise shoot with a graduated split neutral- density filter, such as when you need to darken the sky without darkening the fore- ground of an image. You can use the Gradient tool in ACR to create a similar effect, but the advantage of doing it in Photoshop is that you can customize the filter to the exact size and shape you need. To create a virtual split neutral-density filter, follow these steps: 1. Start by creating a new adjustment layer that produces the desired effect in the area of the image to which you want it to apply. For example, you may create a Levels (or Curves) adjustment layer that darkens the sky in an image by moving the midtones slider to the right. After you’ve made the adjustment, click OK in the dialog box for the adjustment to apply the settings on the layer. 2. Select the Gradient tool from the Tools panel (the shortcut key is G). On the Options bar, click the drop-down list for the gradient editor, and choose the first gradient thumbnail on the list, which is the Foreground to Background gradient. Next, select the Linear option for the Gradient tool on the Options bar (shown in Figure 6.29), which is the first in the set of five buttons allowing you to choose a style for your gradient. Figure 6.29 To use a gradient on a layer mask, select the Foreground to Background gradient with the Linear option from the Options bar. 3. Press D to set the colors to the defaults of black and white, and set white to the foreground color (pressing X to switch foreground and background colors if necessary). You’re now ready to create a gradient that transitions from white to black. 4. You want to create the gradient on the layer mask for the adjustment layer you just created, so make sure that is the active layer in the Layers panel. Then click and drag on the image to create a gradient: the foreground color starts where you first click, with a smooth gradation to the background color where you release the mouse, as shown in Figure 6.30. The length of the line you drag determines the distance over which the gradient transitions, and the direction 607343c06.indd 263 4/12/10 11:42:55 PM 264 c h a p t e r 6: EXPOSURE ADJUSTMENTS ■ determines the angle of that gradient. To lock the gradient to 45° increments, simply hold the Shift key as you drag. Figure 6.30 Draw the gradient on the layer mask so the adjustment tapers from adjusted to nonadjusted areas. 5. In the example of darkening the sky, click the area of sky that represents the lowest area you still want the adjustment to affect completely, and drag down- ward to the point where you don’t want any effect at all. You don’t need to drag across the entire image—just the area where the transition should occur. If you’re not happy with the initial gradient you created, simply click and drag again to replace the gradient with a new one. The result is an adjustment that blends smoothly, from applying completely in one area of the image to having no effect on another area (see Figure 6.31). Figure 6.31 By applying a gradient mask to the adjustment, you’re able to produce an adjustment that gradually blends, as with the darkened sky in this example. Ph oto by Jo sh An on 607343c06.indd 264 4/12/10 11:42:56 PM 265 ■ SAFE DODGE AND BURN LAYERS If your image requires an odd shape to the split neutral-density filter, you can modify the layer mask by painting on it to add or remove the effects where necessary. This can be useful when shooting in the mountains where the sky may be very light but the mountains dark, and the sky area may be V-shaped. Safe Dodge and Burn Layers Dodging and burning are techniques borrowed from the wet darkroom, where you can use your hands or various instruments to block light from specific areas of an image. The longer the light from the enlarger strikes any given area, the darker that area will be. Blocking light to small areas during exposure is referred to as dodging and results in the blocked areas being lighter in a print than they otherwise would have been. Burning is the opposite: blocking light from most of the image so you can concentrate light for a portion of the exposure on one particular area, darkening that area of the print. In Photoshop you can produce similar effects. In fact, Photoshop includes Dodge and Burn tools on the Tools panel, but we don’t recommend using them because you must apply them directly to an image layer, and they don’t offer the exibility of the method we’ll present here. However, an advantage they offer is that you can set them to affect only the shadows, midtones, or highlights. If you opt to use these tools, do so on a copy of the Background layer. Then set the tonal range on the tool Options bar and check the option to Protect Tones. Reduce the exposure to about 10–15% as a starting place. When you release the cursor and go over an area again, the effect is cumulative, so you can gradually build up the amount of dodging or burning for a nicely controlled result. Setting Up The method we recommend for dodging and burning uses one layer for dodging and another for burning, and takes advantage of layer masks and layer blending modes. Blending modes are different ways of combining layers. So far all the layers we’ve worked with in the examples have been in Normal mode, but Photoshop contains numerous algo- rithms for different ways to combine two layers. You can combine layers so that the tonal values are added together or multiplied, or the darker value used, or the lighter values, and so on. You don’t have to become an expert on each of the algorithms; we’ll use just two of them here: Screen and Multiply. We’ll talk more about blending modes in Chapter 9, “Creative Effects.” Note: We prefer this method to the older Overlay method because it’s more forgiving and easier to use. Although setting up the dodging and burning requires a lot of steps, the procedure is easy and can be automated by creating an action (see Chapter 11, “Time-Savers”). To set up layers to use for dodging and burning, do the following: 1. Create a new Levels adjustment layer, but do not make any changes. 607343c06.indd 265 4/12/10 11:42:56 PM 266 c h a p t e r 6: EXPOSURE ADJUSTMENTS ■ 2. Double-click directly on the name of the layer (Levels1), and change it to Dodge. 3. In the Blending Modes drop-down menu on the Layers panel, choose Screen, as shown in Figure 6.32. The entire image will become one full stop lighter, which in most images means that it will instantly be overexposed. Don’t worry—we’re not going to leave it that way for long! Figure 6.32 Take advantage of blending modes to create dodge and burn layers that can be modied easily. 4. In the menu bar, choose Edit > Fill > Use Black, and click OK. The layer mask should now be black, and your image should look the way it did before we began setting up for dodging and burning. 5. Create another Levels adjustment just as you did in Step 1, and name it Burn. 6. Change the blending mode of this layer to Multiply. 7. In the menu bar, choose Edit > Fill > Use Black, and click OK. 8. Select the Brush tool by selecting it on the Tools panel or by pressing B on your keyboard. Be sure to use a soft-edged brush, as shown in Figure 6.33. Figure 6.33 Use a soft-edged brush when dodging and burning your image with this method. 607343c06.indd 266 4/12/10 11:42:56 PM 267 ■ SAFE DODGE AND BURN LAYERS 9. Set the opacity of the brush to 15%, although you may want to adjust this as you proceed since it controls the strength of the dodging and burning. Note: It’s important to set the brush to the Normal blending mode in the tool Options bar, while the layer itself is set to Multiply or Screen in the Layers panel. Note: If you’re using a tablet, you can also use pen pressure of the stylus to determine the Opacity setting when dodging and burning with this method. 10. Press D to set the colors on the color boxes in the Tools panel to their default of black foreground and white background. Note that you can switch the fore- ground and background colors by pressing X as you’re working, allowing you to easily switch between black and white. Now you’re ready to apply selective lightening and darkening to the image. Painting with Light With your new layers and the Brush tool properly configured, you’re ready to start painting with light. Paint with white using the brush at a reduced opacity on the appropriate layer to lighten or darken your image. Although it appears that you’re painting directly on your image, you’re actually painting on the layer mask. Because you’re painting at a reduced opacity, the result is relatively modest. If necessary, you can paint over areas multiple times to build up an effect. The best effect is usually subtle. When people look at the final image, they shouldn’t get the impression that you were using dodging and burning techniques. However, when you toggle the vis- ibility of the dodge and burn layer off and on, you’ll see a difference between the images. It’s important to understand the behavior of the Brush tool when you’re work- ing at a reduced opacity for this technique. As long as you hold down the mouse but- ton, the effect does not accumulate no matter how many times the mouse passes over a particular area. However, if you release the mouse and start painting again, the effect is uneven if you partially overlap areas you’ve previously painted. Therefore, it’s important that you click and hold the mouse button while painting until you’ve covered the entire area you want to adjust. Then release the mouse and start painting again in additional areas you’d like to change. Dodging and burning are two of our favorite techniques in Photoshop. We appreciate the capability to paint with light, bringing out details in various areas of the image or simply emphasizing particular features (see Figure 6.34). 2. Double-click directly on the name of the layer (Levels1), and change it to Dodge. 3. In the Blending Modes drop-down menu on the Layers panel, choose Screen, as shown in Figure 6.32. The entire image will become one full stop lighter, which in most images means that it will instantly be overexposed. Don’t worry—we’re not going to leave it that way for long! 4. In the menu bar, choose Edit > Fill > Use Black, and click OK. The layer mask should now be black, and your image should look the way it did before we began setting up for dodging and burning. 5. Create another Levels adjustment just as you did in Step 1, and name it Burn. 6. Change the blending mode of this layer to Multiply. 7. In the menu bar, choose Edit > Fill > Use Black, and click OK. 8. Select the Brush tool by selecting it on the Tools panel or by pressing B on your keyboard. Be sure to use a soft-edged brush, as shown in Figure 6.33. Figure 6.33 Use a soft-edged brush when dodging and burning your image with this method. 607343c06.indd 267 4/12/10 11:42:57 PM 268 c h a p t e r 6: EXPOSURE ADJUSTMENTS ■ Figure 6.34 Dodging and burning allow you to enhance detail or add drama to various areas of your image with tremendous exibility, producing an image that has been adjusted in a subtle way but with a big dierence in the nal result. Ph oto by EllEn An on Correcting Mistakes Of course, now and then you may be less than satisfied with an adjustment you’ve made when using this technique. Fortunately, because you apply it using a layer mask, it’s easy to fix mistakes even if it’s too late to simply undo a step on the History panel. 607343c06.indd 268 4/12/10 11:42:59 PM 269 ■ THE SHADOWS/HIGHLIGHTS ADJUSTMENT There are two basic ways to correct your mistakes. If you were painting with white as your foreground color, make black the foreground color, or vice versa, and set the opacity to 100%. Paint over the problematic area, and begin again. Alternatively, if you are dissatisfied with all the dodging or burning you did, return to Edit > Fill > Use Black, and reset the layer mask to black. Then you can start over. Try It! To practice dodging and burning, open the image DodgeBurn from www.sybex.com/ go/photoshopnature , and use the method presented here to add drama to the rock formation, enhancing texture and contrast. The Shadows/Highlights Adjustment The Shadows/Highlights adjustment is an excellent way to reveal subtle detail in the shadow and/or highlight areas of your images. Although you could theoretically produce similar results with sophisticated use of Curves, the Shadows/Highlights adjustment is far easier to use when you need to recover detail that has been lost in shadow or highlight areas because of excessive contrast. It’s similar to the Fill Light and Recovery sliders in ACR, which we covered in Chapter 3, but it has additional controls so you can fine-tune the results. Note: Some photographers are tempted to try to use Shadows/Highlights to fix all their exposure problems. We don’t recommend that because the Shadows/Highlights adjustment works by reducing contrast. That’s fine for small tonal ranges, but it’s not usually a good idea to do throughout the entire image. We find it’s far more effective to limit the Shadows/Highlights tool to recovering detail in the deep shadows and recovering highlights in very light areas. Although you can’t apply the Shadows/Highlights adjustment as an adjustment layer, you can use it as a Smart Filter. As we discussed in Chapter 5, “Workows and First Steps,” a filter that’s applied as a Smart Filter behaves similarly to an adjustment layer. The advantage of using it as a Smart Filter is that you can tweak the settings as needed, and you can add a layer mask to it to target the effects to certain areas of your image. For example, perhaps you have a portrait of a dark animal against a dark background. You may want to reveal details in the shadows of the animal but not in the background. We recommend using the Shadows/Highlights adjustment early in your work- ow, as the first step after you open the raw file as a Smart Object. To do so, take these steps: 1. If your Background layer is not already a Smart Object, you’ll need to convert it to one by choosing Filter > Convert for Smart Filters. That way, you can use Shadows/Highlights as a Smart Filter. 607343c06.indd 269 4/12/10 11:42:59 PM . light for a portion of the exposure on one particular area, darkening that area of the print. In Photoshop you can produce similar effects. In fact, Photoshop includes Dodge and Burn tools. matter how many times the mouse passes over a particular area. However, if you release the mouse and start painting again, the effect is uneven if you partially overlap areas you’ve previously painted our favorite techniques in Photoshop. We appreciate the capability to paint with light, bringing out details in various areas of the image or simply emphasizing particular features (see Figure