Tài liệu Photoshop cs5 by Dayley part 62 pps

Part IV: Enhancing, Correcting, and Retouching 430 On the Web Site The project used to create the image shown in Figure 13.42 can be found on this book’s Web site as Figure13-42.psd. Check out the file on the Web site to really see the color and lighting changes in effect. You can use the Curves Adjustment layer to play around with the Curves tool and see the effect of adding and adjusting points. n Using the Match Color Tool to Change Colors The Color Match tool, shown in Figure 13.43, can use the color composition of one image to auto- matically adjust the color composition of another. This helps the images match much more closely when placed side by side. One of the best options when you need to color correct several photos from the same shoot is the Color Match tool. For example, when you are color correcting a set of photos that are washed out a bit from UV interference, you see a large change when you adjust the hue and saturation to bring back the color. As you work with more images your eyes adjust more to the color corrected images and you tend to overcorrect more. The result is that the final images don’t match the initial images. FIGURE 13.43 The Color Match tool provides several options to control how colors are adjusted in a target image by using the colors in a source image. 20_584743-ch13.indd 43020_584743-ch13.indd 430 5/3/10 10:34 AM5/3/10 10:34 AM Chapter 13: Lighting and Color Adjustments 431 Open the Color Match tool by selecting Image ➪ Adjustments ➪ Color Match from the main menu. When applying a color match to an image you can use the following options to control the color matching process: l Target: Shows the image and layer that will be affected by the color match. This option also shows the color mode of the target image. Note Only the selected layer in the destination file will be affected by the color match. n l Ignore Selection when Applying Adjustment: When selected, the color match applies to the entire image instead of just a selection. Note A great feature of the Color Match tool is that you can apply the color matching change to a selection rather than the entire image. For example, you may want to change the background colors without changing the sub- ject’s skin tones. n l Luminance: Adjusts the brightness of the color match adjustment. l Color Intensity: Adjusts the color saturation applied by the color match. Increasing this value makes the colors pop out more; decreasing makes the color change more subtle. l Fade: Adjusts the percentage of color match adjustment to apply to the image. A value of 0 means the full color match adjustment. A value of 100 means no color match adjust- ment. l Neutralizes: Neutralizes color casts in the image, reducing the effects of the color match adjustment that can result in a general color cast. It is a good idea to at least try this option when correcting images. You may not always notice that the color match has resulted in a color cast. l Use Selection in Source to Calculate Colors: Specifies to use only the selected area in the source image to calculate colors for the color match. Tip It is usually best to use selected areas of known colors to apply the color adjustment to images. This can reduce color casts and make more accurate adjustments. For example, you may want to select a person’s face in both the source and target images to make sure skin tones match. n l Use Selection in Target to Calculate Adjustment: Specifies to use only the selection in the target image to calculate the color match adjustment. l Source: Specifies the source image from a drop-down list. All open documents in Photoshop appear in the list. l Layer: Specifies the layer in the source file to use. l Load Statistics: Allows you to load a previously saved set of color statistics and use those instead of a source image. 20_584743-ch13.indd 43120_584743-ch13.indd 431 5/3/10 10:34 AM5/3/10 10:34 AM Part IV: Enhancing, Correcting, and Retouching 432 l Save Statistics: Allows you to save the statistics from the layer of image specified by the Source and Layer options. This allows you to store a specific set of colors that you can use later to adjust other images. l Source View: Displays the image specified by the Source and Layer options so you can verify that you have the correct image selected. Figure 13.44 shows an example of using the color in one image to adjust the colors in another. The colors in the source image have already been adjusted to a desired level. The color match tool takes the color composition from the source image and applies it to the target image, resulting in a much better color match. FIGURE 13.44 The Color Match tool adjusts the colors in a target image by using the colors in a differ- ent source image. Source Color MatchedTarget 20_584743-ch13.indd 43220_584743-ch13.indd 432 5/3/10 10:34 AM5/3/10 10:34 AM Chapter 13: Lighting and Color Adjustments 433 On the Web Site The project used to create the image shown in Figure 13.44 can be found on this book’s Web site as Figure13-44.psd. This file contains both the original layer and the color matched layer so you can see the results of applying the color match. n Converting HDR Images to 8 Bits Per Channel The HDR Toning tool provides an incredible amount of control when adjusting the color and tone of 32-bits-per-channel HDR images to convert them to 8-bits-per-channel images. Tip Although the HDR Toning tool is designed to convert HDR images to 8-bits-per-channel images, it can also be applied to non-HDR images. I’ve found that I can sometimes get better results using the HDR Toning tool than a simple levels adjustment. After applying the adjustment, you still get the message saying that the image is converted to an 8-bits-per-channel image, but because it was already an 8-bits-per-channel image it won’t matter. n To access the HDR Toning tool, shown in Figure 13.45, select Image ➪ Adjustments ➪ HDR Toning from the main menu or select Image ➪ Mode ➪ 8-Bits/Channel from the main menu. From the HDR Toning tool you can make the following lighting and color adjustments: l Preset: Allows you to select one of Photoshop’s predefined HDR tonal adjustments or specify Custom to create your own. The button next to the Preset drop-down menu allows you to save the current settings to a file as well as load previously saved presets. l Method: Allows you to specify one of the following methods used by the toning tool to adjust the lighting and color: l Exposure and Gamma: Allows you to manually adjust the brightness and contrast of the HDR image. Only those two settings will be available in the HDR Toning tool. l Highlight Compression: Automatically compresses highlight values in the HDR image so they match the range of luminance values that 8-bits-per-channel images support. None of the following options will be available. l Equalize Histogram: Automatically compresses the dynamic range of the HDR image while trying to preserve some contrast. None of the following options will be available. l Local Adaptation: Allows you to adjust the following options in the HDR image. The HDR Toning utility will use the values to calculate the amount of correction necessary for local brightness regions throughout the image. l Radius: Specifies the area size used to define local brightness. l Threshold: Specifies how far apart the level values for two pixels must be before they are no longer part of the same brightness region. 20_584743-ch13.indd 43320_584743-ch13.indd 433 5/3/10 10:34 AM5/3/10 10:34 AM Part IV: Enhancing, Correcting, and Retouching 434 FIGURE 13.45 The HDR Toning tool allows you to quickly adjust the lighting and color of HDR images. l Gamma: Allows you to make gamma correction to the tones of the image. l Exposure: Allows you to adjust the exposure up and down. Remember that the dynamic range of the HDR images contains multiple levels of exposure. l Detail: Specifies a percentage amount of detail to preserve when making the other adjustments. l Shadow: Allows you to adjust only the levels of the shadow (darker) tones up and down. l Highlights: Allows you to adjust only the levels of the highlight (lighter) tones up and down. 20_584743-ch13.indd 43420_584743-ch13.indd 434 5/3/10 10:34 AM5/3/10 10:34 AM Chapter 13: Lighting and Color Adjustments 435 l Vibrance: Adjusts the intensity of colors in the image. l Saturation: Adjusts the saturation of color in the image while trying to minimize the amount of clipping that results. l Toning Curve and Histogram: Allows you to use a curve tool to adjust the tones in the image. Summary This chapter discussed most of the tools available in Photoshop to adjust the color and lighting in images. Although color and lighting changes are all basically just adjusting the values of color channels in the images, several tools make it simple to focus on specific adjustments in images. In this chapter, you learned the following: l How to use the Exposure tool to fix lighting problems in images. l Using the Shadows/Highlights tool allows you to quickly adjust the upper and lower color levels in an image. l Photoshop can simulate the effect of using a lens filter on a photo that was taken without one. l How to replace one color with another to completely change the look of a photo. l The best methods for creating black and white photos from color images. l How to adjust individual color channels to make some colors pop out while not affecting the other colors. l The Curves tool is extremely powerful and flexible in restoring detail to images with severe lighting problems. 20_584743-ch13.indd 43520_584743-ch13.indd 435 5/3/10 10:34 AM5/3/10 10:34 AM 20_584743-ch13.indd 43620_584743-ch13.indd 436 5/3/10 10:34 AM5/3/10 10:34 AM . far apart the level values for two pixels must be before they are no longer part of the same brightness region. 20_584743-ch13.indd 43320_584743-ch13.indd 433 5/3/10 10:34 AM5/3/10 10:34 AM Part. 5/3/10 10:34 AM5/3/10 10:34 AM Part IV: Enhancing, Correcting, and Retouching 432 l Save Statistics: Allows you to save the statistics from the layer of image specified by the Source and Layer options that will be affected by the color match. This option also shows the color mode of the target image. Note Only the selected layer in the destination file will be affected by the color match. n l