tailieunhanh - Tài liệu Photoshop cs5 by Dayley part 49

Chỉnh sửa mặt nạ Sau khi một hình ảnh thu nhỏ mặt nạ đã được đặt trong bảng Layer, bạn có thể chỉnh sửa nó. Bạn có thể chỉnh sửa các mặt nạ bằng cách sử dụng hình ảnh, các kênh, hoặc bảng điều khiển các mặt nạ. | Part III Selections Layers and Channels FIGURE The clipping mask used the spider as a template to cut out the jack-o-lantern image for spooky effect. Editing masks After a mask thumbnail has been placed in your Layers panel you can edit it. You can edit the mask using the image the channels or the Masks panel. Edit a mask by painting on the image To edit the mask using the image you must have the mask selected in the layer. Make sure the mask thumbnail has a white highlight around it rather than the image thumbnail. This is sometimes hard to see so click back and forth a couple of times to see the difference. After you have selected the mask you can use the Brush and Eraser tools to add to or subtract from the masked area. Using the Brush adds to the mask and using the Eraser subtracts from it. Use these tools directly on your image. The only difference you see is a change in the masks effects. Depending on what those changes are this might not be the ideal way to edit your mask because it is hard to be precise if the effects of the mask aren t obvious. For instance the mask in Figure is placed over an exposure adjustment and changes made to this mask simply lighten or darken the image a little a hard change to see. Note Reducing the opacity on either the Brush or the Eraser tool paints levels of grayscale creating a semi-permeable area of your mask. Edit masks using the Channels panel A better option for editing this mask is to use the Channels panel. With the mask selected in the Layers panel open the Channels panel as shown in Figure . The channels panel contains the color channels found in your image but it also contains any masks placed in your image. When you open the Channels panel the mask channels are not visible. If you turn the visibility icon on a rubylith mask appears in your image reminiscent of the Quick Mask. Now as you make changes to the mask you can see them clearly. 332 Chapter 10 All about Layers FIGURE The white outline