tailieunhanh - Adobe Photoshop 6.0- P5

Adobe Photoshop P5: Adobe Photoshop delivers powerful, industry-standard image-editing tools for professional designers who want to produce sophisticated graphics for the Web and for print. Included with Photoshop is ImageReady and its powerful set of Web tools for optimizing and previewing images, batch-processing images with droplets in the Actions palette, and creating GIF animations. Photoshop and ImageReady combined offer a comprehensive environment for designing graphics for the Web | 120 LESSON 5 Masks and Channels Using alpha channels In addition to the temporary masks of Quick Mask mode you can create more permanent masks by storing and editing selections in alpha channels. You create a new alpha channel as a mask. For example you can create a gradient fill in a blank channel and then use it as a mask. Or you can save a selection to either a new or existing channel. An alpha channel has these properties Each image can contain up to 24 channels including all color and alpha channels. All channels are 8-bit grayscale images capable of displaying 256 levels of gray. You can add and delete alpha channels. You can specify a name color mask option and opacity for each channel. The opacity affects the preview of the channel not the image. All new channels have the same dimensions and number of pixels as the original image. You can edit the mask in an alpha channel using the painting and editing tools. Storing selections in alpha channels makes the selections permanent so that they can be used again in the same image or in a different image. -From Adobe Photoshop online Help Saving a selection as a mask Now you ll save the egret selection as an alpha channel mask. Your time-consuming work won t be lost and you can use the selection again later. Quick masks are temporary. They disappear when you deselect. However any selection can be saved as a mask in an alpha channel. Think of alpha channels as storage areas for information. When you save a selection as a mask a new alpha channel is created in the Channels palette. An image can contain up to 24 channels including all color and alpha channels. You can use these masks again in the same image or in a different image. Note If you save and close your file while in Quick Mask mode the quick mask will show in its own channel next time you open your file. However if you save and close your file while in Standard mode the quick mask will be gone the next time you open your file. 1 To display the Channels