tailieunhanh - Photoshop cs5 by steve Johnson part 64

Chuẩn bị một Ảnh cho Web Giảm kích thước của bức ảnh là một món quà thiết lập của riêng cụ thể của nó các vấn đề, và Photoshop nói đến việc cứu hộ với các giải pháp. Đối với các hình ảnh chụp, định dạng tốt nhất để sử dụng là JPEG (Joint Photographic Experts Group) định dạng. Định dạng này làm giảm kích thước tập tin bằng cách loại bỏ thông tin hình ảnh (mất dữ liệu nén). Ví dụ, một tập tin TIFF 1 MB không nén có thể được giảm tới 20 KB hoặc 30 KB. | Preparing a Photograph for the Web Reducing the size of a photograph presents its own particular set of problems and Photoshop comes to the rescue with solutions. For photographic images the best format to use is the JPEG Joint Photographic Experts Group format. This format reduces file size by removing image information lossy compression . For example a 1 MB uncompressed TIFF file can be reduced to 20 KB or 30 KB using JPEG compression. That reduces the download time of the image on a 33 KB modem from15 minutes to 10 seconds. While that is quite a reduction it also means most of the image colors have been removed and the remaining colors are dithered simulated to fool the eyes into seeing colors that are no longer in the image. Highly compressed JPEG images look good on a monitor but fare poorly when sent to a printer. If you re working with a 16-bit document you can save it in the JPEG format 8-bit using the Save As command without having to change the bit depth before hand New . Prepare a Photograph for the Web Open a photographic document. Click the File menu and then click Save As. Enter a name for the file in the Save As box. Click the Save In Win or Where Mac list arrow and then select a location in which to save the file. Click the Format list arrow and then click JPEG. Click Save. 0 400 Chapter 16 Select from the following JPEG Options Matte. The JPEG format does not support transparency. Click the Matte list arrow and then select the color with which to fill transparent areas within the active document. Quality. The Quality option determines the amount of image information loss. Enter a value from 1 to 12 the higher the value the more information is retained thus creating a larger file. Baseline Standard . The format is recognized by most browsers. Baseline Optimized. Produces optimized color and a slightly smaller file size but is not supported by older browsers. Progressive. Displays a series of increasingly detailed scans as the image downloads. The .