tailieunhanh - PHOTOSHOP CS4 QuickSteps- P12

PHOTOSHOP CS4 QuickSteps- P12: QuickSteps books are recipe books for computer users. They answer the question “How do I.?” by providing quick sets of steps to accomplish the most common tasks in a particular program. The sets of steps are the central focus of the book. QuickSteps sidebars show you how to quickly do many small functions or tasks that support the primary functions. Notes, Tips, and Cautions augment the steps, yet they are presented in such a manner as to not interrupt the fl ow of the steps | 10 87654321 Figure 9-13 Reassign brightness values within the selection to add detail to the selection. 2. Switch back to Standard mode and then on the Channels panel click the title of the channel that shows the most contrast and detail in this example the Green channel. 3. Press CTRL CMD L to display the Levels command. 4. You need to alter the Levels so that the black midpoint and white points all lie somewhere around the area on the histogram where pixels actually exist. Drag the Black Point at left input slider to the right. Then drag the Midpoint slider to the left to open the midtones or to the right to create more contrast. Finally drag the White Point slider to the left until you can clearly see the texture in the selected area. Click OK and then press CTRL CMD D to deselect the marquee. As you can see in Figure 9-13 much more detail has been revealed in the little girl s sweater. 5. Return to the RGB view of the photo by clicking the RGB channel at the top of the Channels panel. Save your work now. You will indeed see color casting in the color composite RGB view of the photo now. This is okay however the finished image will be black and white disregarding the colors you now see in the photo. Even Out the Overall Photo Tones In your own work and certainly in this example image overall lighting can look awkward particularly when a camera flash was used. If your photo has a hot spot in a corner or the center with steep fall-off toward the edges one quick fix is to use Quick Mask mode and the Gradient tool to create a reverse fall-off in a selection and then use Levels to correct the image 1. Double-click the Edit In Quick Mask Mode button on the Tools panel. 2. In the Quick Mask Options box click the Color Indicates Selected Areas. Photoshop considers black to be a color. Click OK and you re now editing in Quick Mask mode. 3. Click the Gradient tool. 4. Choose a style from the Options bar that best describes the exposure fall-off problem If one side of the