Adobe 13101332 User Guide - Page 457

Adobe Photoshop Help Using Help | Contents | Index Saving and Exporting Images Back 457 Generic PDF files Are created using applications other than Photoshop, such as Adobe Acrobat and Adobe Illustrator, and can contain multiple pages and images. When you open a Generic PDF file, Photoshop rasterizes the image. PICT File PICT format is widely used among Mac OS graphics and page-layout applications as an intermediary file format for transferring images between applications. PICT format supports RGB images with a single alpha channel, and indexed-color, grayscale, and Bitmap-mode images without alpha channels. PICT format is especially effective at compressing images with large areas of solid color. This compression can be dramatic for alpha channels with their large areas of white and black. When saving an RGB image in PICT format, you can choose either a 16-bit or 32-bit pixel resolution. For a grayscale image, you can choose from 2, 4, or 8 bits per pixel. In Mac OS with QuickTime installed, four JPEG compression options are available. Note: In ImageReady, PICT format is supported in Mac OS only. PICT Resource (Mac OS) A PICT resource is a PICT file contained in a Mac OS file's resource fork-for example, an application's splash screen or the contents of the Scrapbook. PICT Resource format supports RGB images with a single alpha channel, and indexed-color, grayscale, and Bitmap-mode images without alpha channels. You can use the Import command or the Open command to open a PICT resource. When saving a file as a PICT resource, you can specify the resource ID and resource name. As with other PICT files, you also specify bit depth and compression options. Pixar The Pixar format is designed specifically for high-end graphics applications, such as those used for rendering three-dimensional images and animation. Pixar format supports RGB and grayscale images with a single alpha channel. PNG Developed as a patent-free alternative to GIF, Portable Network Graphics (PNG) format is used for lossless compression and for display of images on the World Wide Web. Unlike GIF, PNG supports 24-bit images and produces background transparency without jagged edges; however, some Web browsers do not support PNG images. PNG format supports RGB, indexed-color, grayscale, and Bitmap-mode images without alpha channels. PNG preserves transparency in grayscale and RGB images. QuickTime Movie (ImageReady) QuickTime Movie format is a cross-platform format used for time-based data, such as video and audio. In ImageReady, you can save animations as QuickTime movies and open existing QuickTime movies as animations in order to optimize them for the Web. Note: In Windows, QuickTime Movie format is visible in the Files of Type pop-up menu only when QuickTime is installed on your computer. Using Help | Contents | Index Back 457