Photoshop cs5 cho nhiếp ảnh gia part 21 pps

120 c h a p t e r 3: ADOBE CAMERA RAW ■ Snapshot Tab It’s now possible to create and save multiple versions of an image. For example, you could create a black-and-white version as well as a color version or one with a very different crop, etc. When you have adjusted the image in a way that you’d like to keep, go to the Snapshot tab and use the Snapshot icon to create a snapshot of the image looking this way. That way you can further modify the image any way that you like. To return the image to the snapshot, open the Snapshot tab and click the snap- shot or choose Apply Snapshot from the fly-out menu at the top right of the tab and choose the desired snapshot. To delete a snapshot, select it and then click the Trashcan icon in the lower right of the interface. You can make multiple snapshots for each image, and open each simultaneously into Photoshop. This is particularly useful with very contrasty images if you want to create two versions to merge together to extend the dynamic range. This way you can use the raw file to access highlight or shadow information that may not be accessible in the converted image that HDR Toning uses. (We cover single-image HDR Toning in Chapter 8, “Composites.”) Making Localized Adjustments ACR includes the ability to make localized adjustments right in the raw converter. This means that you can make adjustments to specific parts of your image while still accessing all the information your sensor captured rather than having to wait and use the converted file in Photoshop with selections and layer masks. It’s worth spending the time to get comfortable with these new tools. At first they may seem a bit quirky, but if you follow our instructions, you’ll have them under control in no time! There are two tools you can use: the Adjustment Brush and the Graduated Filter . Using the Adjustment Brush When you click the Adjustment Brush icon, the interface changes, as shown in Fig- ure 3.22. The first controls consist of three radio buttons that let you specify whether you’re making a new adjustment, adding to or modifying an existing adjustment, or erasing part of an adjustment. Every time you use a new Adjustment Brush on the image, a pin appears on the image. You can toggle the visibility of the pins by checking Show Pins in the lower-left part of the interface. To remove a pin, click on it and press Delete. Lower in the interface are sliders to control the features of each brush. Size refers to the size of the brush, and Feather controls whether the edges of the adjust- ment blend in gradually to the image or have a discrete edge. Flow controls the rate the correction is applied or, in other words, how rapidly the effect flows out of the brush. Density refers to the opacity of the effect. 607343c03.indd 120 4/12/10 11:48:37 PM 121 ■ MAKING LOCALIZED ADJUSTMENTS Figure 3.22 When you brush in an adjustment, toggle the mask overlay visibility to help ne-tune the changes. Near the bottom of the panel are options for Auto Mask and Show Mask, and a color swatch. The Auto Mask option helps you constrain your brushed effects to a certain area based on the color range. By checking the Show Mask option, you’ll see a mask showing what areas are affected by your adjustment. The color swatch indicates the color that will be used for the mask overlay. Click on it to access the Color Picker, shown in Figure 3.23, for further control of the overlay. When you hover the cursor over a pin with Show Mask selected, you’ll see the mask associated with that pin. Figure 3.23 The Color Picker enables you to control the appearance of the mask overlay. The bulk of the interface contains seven parameters that you can apply either singly or in combination. By default the sliders are not set to 0. We double-click them to set them to 0, and then adjust them according to whatever effects we’re after. The settings are sticky, meaning that the next time you access the Adjustment Brush con- trols, they will be set the way you left them. 607343c03.indd 121 4/12/10 11:48:37 PM 122 c h a p t e r 3: ADOBE CAMERA RAW ■ Note: It’s hard to know exactly what values to set in the sliders before you use the brush. Remem- ber that you don’t have to guess the initial settings exactly right. When you change to the Add mode, you can refine the settings visually. That makes it a lot easier! The +/– buttons to the sides of each slider access presets and adjust the sliders in increments. The Color option, which by default is set to a blank rectangle with an X in it, contains presets to use to warm or cool parts of the image. Click on it to access more options, as shown in Figure 3.24. Figure 3.24 Clicking the color box accesses additional options for modifying the color cast. Begin by clicking New radio button and then setting the sliders for the desired effect. Most of the time you’ll want Auto Mask selected. Then begin brushing in the effect. When you stop, the top radio button will automatically change to Add. At that point you can brush an additional area with the same settings, or you can modify the sliders to tweak the change you just brushed. Click the Erase radio button to change the brush into an eraser to remove the effect from an area. Remember to zoom in as far as necessary to work accurately! We have no doubt that the more you use Adjustment Brushes, the more impressed you will be with them! Using the Graduated Filter The Graduated Filter (Figure 3.25) is similar to the Adjustment Brush in terms of the adjustments it can apply. The difference is that rather than brushing the adjustments directly where you want them, you apply them using a gradient. To begin, select the New radio button and then adjust the sliders. Initially you’re making a best guess with the slider settings. You can refine your choices when you click the Edit radio button. Each time you click and drag on the image, a new gradient appears, beginning and ending where you clicked and dragged. To remove a gradient, click on one of the pins and press Delete. Using the Graduated Filter, you can simulate not only a graduated neutral- density filter, but also a filter that controls saturation, contrast, clarity, and so forth. These two tools in ACR are extremely powerful and in many cases remove the need for further work in Photoshop. Be sure to take advantage of them! 607343c03.indd 122 4/12/10 11:48:37 PM 123 ■ MAKING TARGETED ADJUSTMENTS Figure 3.25 Using the Graduated Filter you can apply a variety of adjustments as a gradient so that you can specify where they fade in and out. Making Targeted Adjustments In addition to clicking directly on each tab and adjusting sliders, it’s possible to use the Targeted Adjustment tool to make certain adjustments. When you click this tool and hold the lower-right corner, a pop-up menu appears, as shown in Figure 3.26, with five options: Parametric Curve, Hue, Saturation, Luminance, and Grayscale Mix. Choose the desired adjustment, then place the cursor on the image and drag. The appropriate tab and slider in ACR will be automatically selected. In the case of color adjustments, the changes will apply to the specific color range clicked. If Para- metric Curve is chosen, drag the cursor to the left to darken an area and to the right to lighten it. You can click in multiple areas to lighten and darken them selectively. If Grayscale Mix is selected, the entire image will immediately be converted to a black- and-white image. Then click and drag the cursor in various areas to lighten or darken those tonal values. Figure 3.26 Using the Targeted Adjustments tool is an easy way to have ACR choose and modify the necessary sliders, while you drag the cursor directly on the image. The difference between using Targeted Adjustments and the Adjustment Brush or Gradient Filter is that Targeted Adjustments are applied throughout the entire image based on tonal values, whereas adjustments made with the Gradient Filter or the Adjustment Brush are applied to a localized area based on the area you select. 607343c03.indd 123 4/12/10 11:48:38 PM 124 c h ap ter 3: A D O B E CA M ER A R AW ■ Setting ACR Workow Options and Saving Files At this point you’re almost done with the ACR interface, but first you have to instruct ACR how you want the converted file saved. Directly below the image preview in the ACR interface is a series of informa- tion that looks like a web link. Click on this information to reveal the ACR Workflow Options dialog box, shown in Figure 3.27. Figure 3.27 Several important settings are found in the Workow Options dialog box. For Photoshop Elements Users: Workflow Options Camera Raw in Elements does not allow you to change the color space, size, or resolution of your raw files, but it does allow you to change the depth by using the Depth drop-down menu. Fur- thermore, Elements does not support Smart Objects. Choosing the Space The Space drop-down menu gives four options for the color working space: A• dobe RGB (1998) P• roPhoto RGB s• RGB IEC61966-1 C• olorMatch RGB Only the first three options are useful for nature photographers (we’ll tell you why shortly). Adobe RGB 1998 is the most frequently used color space for nature photogra- phers seeking to make prints and archive their files, because it is a reasonably wide color space and corresponds fairly well to the color spaces available in most inkjet printers. Many people prefer to use this space as their default color working space. If you’re planning to work with images in 16-bit color (and we recommend you do), you may consider using the ProPhoto RGB workspace, particularly if you have a printer that uses 16-bit files. It’s a wider space than the commonly used Adobe RGB 1998 and will allow you to use some colors that your camera may have captured but that are outside the gamut of Adobe RGB 1998. Some inkjet printers can print some For Photoshop Elements Users: Workflow Options Camera Raw in Elements does not allow you to change the color space, size, or resolution of your raw files, but it does allow you to change the depth by using the Depth drop-down menu. Fur - thermore, Elements does not support Smart Objects. 607343c03.indd 124 4/12/10 11:48:38 PM 125 ■ SETTING ACR WORKFLOW OPTIONS AND SAVING FILES of these colors. Further, if you have some clipping—that is, pixels that are at the extremes of the tonal values—in one or more channels, you may want to see whether changing to the ProPhoto RGB space allows you to capture more detail in those chan- nels. The disadvantage is that if you are converting back to an 8-bit image, you may have more colors that need to be converted than if you had limited yourself to Adobe RGB 1998. This may lead to some posterization or banding. Occasionally, some people may want to use sRGB IEC61966-1. This is a nar- rower color space, but it’s useful if your intended output is limited to projection, email, and/or web usage. If you think that there’s any chance you may want to print the file, we recommend you use either Adobe RGB or ProPhoto RGB and convert to sRGB for the specific use. (See Chapter 4, “Foundations,” for a more complete discus- sion of color spaces.) ColorMatch RGB is a space that is wider than sRGB and narrower than Adobe RGB. This means it may have more colors than you can utilize for web use or projec- tion but fewer than your inkjet printer is capable of printing. Therefore, one of the other spaces is usually a better choice. Choosing the Depth You have the choice of converting your image into a file with 256 possible tonal val- ues (8 bits per channel) or a file with 32,768 possible values (16 bits per channel). The clear advantage to 16-bit is accurate and smooth reproduction of tonal variations. The workflow is as easy for a 16-bit file as for an 8-bit file. The only slight disadvantages are that since the 16-bit file is larger, your computer may process adjustments a little more slowly, you may need more RAM to process the files, and the files will take up more space in memory. Choosing the File Size and Resolution ACR provides a drop-down menu, found under the Size option, listing various file sizes specific to the camera used to take the image. Some of the sizes are marked with a plus sign (+) and some by a minus sign (–). One size has neither; it refers to the native resolu- tion of the image with no interpolation. Most of the time this is the choice you’ll want. If you are optimizing images for a slide show, you may prefer to use a smaller size. Some people prefer to use a larger size if they know they will be creating huge files, believing that the interpolation done by ACR is better than the interpolation done later in Photoshop. We have not found any significant benefit to enlarging the file in ACR, and the drawback is that you are dealing with a larger file size that requires more memory space and longer processing times. If you have cropped the image, the sizes available will reflect the crop. In that case you may prefer to use one of the sizes with a +, depending on the magnitude of the crop and the size of your intended output. As we discuss in Chapter 4, the resolution, expressed in ppi (pixels per inch), merely refers to how tightly or loosely packed the pixels are; it doesn’t change any- thing about the total number of pixels. The actual number of pixels is controlled by the file size that you choose. The resolution you set determines whether pixels are 607343c03.indd 125 4/12/10 11:48:38 PM . capable of printing. Therefore, one of the other spaces is usually a better choice. Choosing the Depth You have the choice of converting your image into a file with 256 possible tonal val- ues. interface. You can make multiple snapshots for each image, and open each simultaneously into Photoshop. This is particularly useful with very contrasty images if you want to create two versions to. make adjustments to specific parts of your image while still accessing all the information your sensor captured rather than having to wait and use the converted file in Photoshop with selections