Photoshop cs5 cho nhiếp ảnh gia part 29 potx

173 ■ SELECTION TOOLS detailed areas, we can make reasonably accurate selections in many cases, as shown in Figure 4.28. Figure 4.28 It was easy to make a reasonably good selection of the penguin by using the Quick Selection tool. We’ll need to use Rene Edge (covered in the next section) to perfect the selection of the tail. Ph oto b y EllEn An on If the selection is not updating fast enough, you may need to drag a little more slowly and continue to hold down the mouse. If you stop dragging and then click elsewhere, the tool will automatically change to Add to Selection. The selection will grow to incorporate the new area but not neces- sarily areas in between the original selection and the new area. To remove an area from the selection, choose the Subtract from Selection option in the Options bar and then drag over the area to be removed. You may need to reduce the size of the tool. In areas of lower contrast, you may need to alternate between adding to and subtracting from the selection. Holding down the Alt/Option key will enable you to rapidly toggle between the two modes. As you do so, Photoshop is actually refining the algorithm to make the selection more accurately and quickly. To further adjust the edges of the selection, click the Refine Edges button, dis- cussed in the next section. Using the Rene Edge Controls The Refine Edge tool (Figure 4.29) has been completely overhauled in CS5 to make it even more powerful and easier to use. Its purpose is to enable you to modify the edges of a selection so that it blends with or separates from the background as needed. When using the selection tools, a Refine Edge button appears on the tool Options bar . It’s also available from within the Masks panel from the Mask Edge button. It is our method of choice for controlling the appearance of the edges of a selection no matter how we made the initial selection. It’s taken the place of the simple Feather command in our workflow and it eliminates the need for the elaborate procedure we used to use, in which we created a layer mask for a selection and blurred the edges of the layer mask. The Refine Edge interface is divided into several sections. View Mode contains options for viewing the selection. By default it places your selection against a white background, but it is sticky and will open with the view you used last. Click the View 607343c04.indd 173 4/11/10 11:04:28 PM 174 c h a p t e r 4: FOUNDATIONS ■ drop-down menu to access other choices. The edges of some selections will show up more easily against black or with the red overlay or even as black and white or against a transparent background. If you can’t easily see the edges of your selection, choose a dif- ferent view. Press F repeatedly to scroll through the different View options (Figure 4.30). Figure 4.29 The Rene Edge dialog box provides tools to perfect the edges of the selection. Standard Quick Mask On Black Figure 4.30 Depending on the image, dierent previews make it easier to see the edge detail of the selection. CS5 has two new Refine Edge View modes. On Layers shows the unmasked image data on its own layer, along with the other image layers below. This enables you to create your own color fill layer right below the masked layer if you’d like to view the 607343c04.indd 174 4/11/10 11:04:30 PM 175 ■ SELECTION TOOLS selection against a different color background. We rarely find this necessary, but in cer- tain tricky situations it might be helpful. The Reveal Layer view disables the layer mask so that you see the entire active layer as though there were no mask (although color decontamination is applied.) It’s a quick way to see how the selection and edges fit into the rest of the image. After you’ve modified the edge, check Show Original, or press P, to compare the new edge with the original. Check the Show Radius box to view the area that’s defined as an edge. That way you’ll know exactly where the Refine Edge tool will affect the selection. Use the Zoom tool and the Hand tool on the upper left of the dialog to increase the magnification to work in detail on certain areas as necessary. The Edge Detection slider is used to help Photoshop choose a narrower hard edge or a wider softer edge containing areas of varying transparency. A selection of a fence against grass would require a fairly hard edge, whereas selecting fur or feathers (or hair) would require an edge with larger areas of transparencies to let the background show through. Increase the Radius slider to choose the width of the edge. For the penguin, Ellen chose a moderately wide radius to help with the tail selection. After setting the Radius slider to the maximum amount of refinement you want, check the Smart Radius option to have Photoshop automatically reduce the level of refinement that occurs around certain localized areas of the mask edge. This way Photoshop can scale down the amount of refinement applied to simpler edges, which decreases the risk of noise artifacts from the background. When only certain areas need a wider edge, click the Refine Radius Tool and brush over the edges you want to enlarge. To select the penguin’s tail feathers, Ellen brushed over the tail several times, and the selection became increasingly more accurate. Choose the Erase Refinements Tool (from the same icon by holding the lower- right corner and clicking the tool from the pop-up menu) to decrease the edge refine- ments in certain areas. When using these tools, it can sometimes be helpful to check the Show Radius option in the View Mode section. Larger radius settings preserve more details along the edges but may include some artifacts. You can remove such artifacts by increasing the Contrast slider in the Adjust Edge section. In addition, increasing the contrast retains gradual transitions in larger areas but makes slightly soft edges crisper. Next adjust the Smooth slider to reduce any jagged edges along the edge of the selection. At times this may cause some fine detail to be lost. In such cases, adjust the Radius slider to recover the detail. The Feather slider is similar to the familiar Feather command from earlier ver- sions of Photoshop. It produces a uniform, gradual blur along the selection edge. The Radius slider is a more sophisticated version of feathering. We recommend primarily using the Radius slider and using Feather just for any fine-tuning the edges need. Moving the Shift Edge slider to the left contracts the selection and moving it to the right expands the selection. In the Output section, by default Output To will be set to either Selection or Layer Mask, depending how you accessed the Refine Edge dialog. If you are on a pixel 607343c04.indd 175 4/11/10 11:04:30 PM 176 c ha p te r 4: FO UN DAT ION S ■ layer (rather than an adjustment layer), you will also have the option to check Decon- taminate Colors. In some cases the edges of the selection will be partially transparent and allow some of the original background color to come through. The Decontami- nate Colors option will change the color of those partially transparent pixels to hide all traces of the original background. Set the amount as needed via the Amount slider. If you use The Decontaminate Colors option, the Output To drop-down menu will automatically change to New Layer with Layer Mask, although you can also choose to output to a new document with or without a layer mask. We primarily choose the New Layer with Layer Mask option. If you create a series of settings that you want to use frequently as your starting place, check the Remember Settings option. By using the Refine Selection tools, you can control the appearance of the edges of your selections to make transitions that blend naturally into the rest of the image. Combining the Quick Select tool and Refine Edges made it quick and easy to accu- rately select the penguin, including the fine details of his tail, as shown in Figure 4.31. Figure 4.31 The new Rene Edge tool made it easy to perfectly select the penguin as well as his tail feathers. For Photoshop Elements Users: Refine Edge The Elements Refine Edge window is more basic than the CS5 tool, providing only Smooth, Feather, and Contract/Expand options, as seen here. Furthermore, the Elements version of Refine Edge has only the Standard and Quick Mask preview modes. 607343c04.indd 176 4/11/10 11:04:31 PM 177 ■ SE LE CT ION TO OL S Creating a Custom Image Border Using Refine Edge It’s easy to create a custom edge border as shown here using the Refine Edge tool. Begin by making a selection with the Rectangular or Elliptical Marquis tool close to the border of the image. Then choose Refine Edge. Experiment with a large Radius setting and then adjust the Contrast, Feather, and Shift Edge settings as desired. Check Smart Radius and see how it affects the result. Use the Refine Radius tool on some of the edges if needed. Photo by EllEn Anon Color Range Tool The Color Range tool is similar to the Magic Wand tool but far more powerful. It enables you to select multiple areas of the same or different colors at one time. It’s particularly useful in selecting skies when there are objects such as trees in the fore- ground. To access it, choose Select > Color Range. We leave the Select drop-down box set to Sampled Colors most of the time, but on occasion we might set it to Highlights or Shadows to make a selection of just those tonalities. While you could use any of the options, most of the other options are more helpful for graphic artists. But if you have a use for a different type of selection, feel free to try it. 607343c04.indd 177 4/11/10 11:04:32 PM 178 c h a p t e r 4: FOUNDATIONS ■ We tend to leave the Selection Preview at the bottom of the dialog set to None initially, but have the preview itself within the Color Range dialog set to Selection (as in Figure 4.32). At times during the selection process, we might change the Selection Preview to Quick Mask, Grayscale, Black Matte, or White Matte to more precisely check the results, but we find that a setting of None provides a good starting place. The Localized Color Cluster option is helpful when you want to make a selec- tion of a color in one part of an image but not in another—for example, in the fore- ground but not the background, or blue sky but not blue water in an image. It helps you to make a more accurate selection quickly. To use Color Range to select the sky (or anything else) in an image, take the following steps: 1. Make certain the Select box is set to Sampled Colors, and use the left eyedrop- per to click an area in your image to specify as the target color. (You can also use the pull-down menu from the Select box, and choose a specific color, such as blue, or highlights, midtones, or shadows; but usually it’s more effective to sample the specific color in the image.) You can click directly on the image or on the small preview in the dialog box. 2. Your selection is white in the preview box. (Selected areas are white, unselected areas are black, and gray areas are blurred selection edges.) 3. Drag the Fuzziness slider to adjust the tolerance. Higher tolerances select more colors; lower values select fewer colors. The preview box shows how the Fuzzi- ness value is affecting the selection (see Figure 4.32). Figure 4.32 With just a couple clicks of the eyedroppers and adjusting the Fuzziness slider, you can easily select a sky from this image. 4. You’ll probably need to use the Add To eyedropper (the one with the + by it) and click additional areas of the background until you have successfully iden- tified the entire sky area. Similarly, you may need to use the Subtract From eyedropper to remove areas from the selection. As you do so, you’ll have to readjust the Fuzziness slider. 607343c04.indd 178 4/11/10 11:04:34 PM 179 ■ SELECTION TOOLS 5. By using one of the overlays, as shown in Figure 4.33, you can more accurately see the boundaries of your selection, making it easier to set the Fuzziness slider. Choose the selection preview that makes it easiest for you to see the edges of your selection. We often find the grayscale view helpful. Figure 4.33 Using the Selection Preview overlay helps you make accurate selections. Ph oto b y EllEn An on 6. If you wanted to select the yellow leaves on the tall tree near the right but not the other yellow leaves, you would check the Localized Color Clusters option (Figure 4.34) and then move the Range slider toward the left to limit the geo- graphic area that Photoshop uses for the selection. By doing this, we were able to make a very specific selection that would have required more work using any of the color-selection tools. (The Range slider is active only when Localized Color Clusters is checked.) 607343c04.indd 179 4/11/10 11:04:35 PM 180 c h a p t e r 4: FOUNDATIONS ■ Figure 4.34 The Localized Color Clusters option makes it possible to limit the area that’s selected when the color appears in multiple parts of the image. 7. When you are happy with your selection, click OK, and Photoshop turns the white area into a selection. 8. If Color Range has identified other areas that you do not want to be selected and you cannot eliminate them using the Subtract From eyedropper, the Fuzzi- ness slider, or the Range slider, use any of the other selection tools (such as the Lasso or Magic Wand tool) to remove them from the selection. Note: You can use more than one color as the basis for your selection by selecting the middle eye- dropper and clicking an additional color in your image. Similarly, you can use the farthest-right eyedrop- per to click a color range to remove from your selection. The Color Range tool tends to create selections with slightly blurry edges, whereas the Magic Wand creates more definite selections with anti-aliased edges. Of course, any selection can be modified using the Refine Edge tool. The Masks panel uses the Color Range tool to help create and adjust layer masks. We’ll talk more about that in Chapter 6. Combining Tools We’ve covered some of the key selection tools here to help you build a foundation for the use of tools within Photoshop as well as get you started on creating selections you’ll use to apply targeted adjustments to your images. In Chapter 8, “Composites,” we’ll explore additional, more advanced ways of making selections. However, we want to stress here that you can mix and match any of the selection tools or methods in Photoshop to create the perfect selection. It’s fine, and often helpful, to begin a selec- tion with one tool and use another tool to refine it, as you saw earlier with the combi- nation of Quick Select and Refine Edges (Figure 4.31). In the workshops we teach, we often see participants getting stuck on a single selection tool for a given task. For example, if they’re trying to create a selection of the sky, they naturally start with the Magic Wand tool. If that tool isn’t providing a good solution in a particular portion of the sky, we often see the person struggling to find just the right Tolerance setting and just the right pixel to click in order to get the 607343c04.indd 180 4/11/10 11:04:35 PM . the next section. Using the Rene Edge Controls The Refine Edge tool (Figure 4 .29) has been completely overhauled in CS5 to make it even more powerful and easier to use. Its purpose is to enable. easily see the edges of your selection, choose a dif- ferent view. Press F repeatedly to scroll through the different View options (Figure 4.30). Figure 4 .29 The Rene Edge dialog box provides. to work in detail on certain areas as necessary. The Edge Detection slider is used to help Photoshop choose a narrower hard edge or a wider softer edge containing areas of varying transparency.