tailieunhanh - Professional Information Technology-Programming Book part 26

Tham khảo tài liệu 'professional information technology-programming book part 26', công nghệ thông tin, kỹ thuật lập trình phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | brightness. For example sometimes I want to make the skin tones just a little lighter or find that it would be better if the sky were a bit darker. Please keep in mind that right now I m only talking about brightness areas that are predominant in a large part of the image and don t have to be isolated by masking. Masked channels come later in the workflow. In case you don t already know adjusting the contrast curve for a given range of brightness is easy 1. Open the Curves dialog press the Cmd Ctrl key and the cursor will become an eyedropper. Click on the tone in the image that is the midtone in the brightness range that you want to adjust. A black dot will appear at precisely that brightness location along the Curve line. 2. Repeat the process for any other brightness tones you want to change. 3. Select each Curve line dot one at a time. For each dot press the Up arrow key to brighten that tone or the Down arrow key to darken it. Press the Left Right arrow keys to move that point to a different position along the curve. If necessary you can isolate the changes you are making to include only a given brightness range by placing double points above and below the curve point that you are moving. Figure 6-9 shows an image and its curve after changing the brightness and contrast of the midtones in the shadows to bring out a bit more detail. Figure 6-9. An image and its curve after changing the brightness and contrast of the midtones in the shadows to bring out a bit more detail. The same Curves adjustment layer can be used to change the color tint of a particular range of brightness. Figure 6-10 shows the before and after of a portrait in which there is a tint reflecting from a nearby wall. This is something you couldn t do in Camera Raw so doing it now is your only chance. You could use the Color Balance adjustment for this job but you d have to make selections to target the tinted area so you couldn t apply the same layer to a series of images. This adjustment is .