tailieunhanh - Photoshop cs5 by steve Johnson part 29

Tìm hiểu về các chế độ màu CMYK Các chế độ màu CMYK là chế độ màu sắc của giấy và báo chí. In ấn (đôi khi gọi là báo chí 4-màu) chuyển đổi màu sắc của hình ảnh vào tỷ lệ phần trăm của CMYK (Cyan, Magenta, Yellow và Black), cuối cùng trở thành màu các tấm trên báo chí. Một lúc, các tấm áp dụng màu sắc cho một tờ giấy, và khi tất cả 4 màu sắc đã được áp dụng, bài viết này có chứa một hình ảnh tương tự như các hình ảnh CMYK tạo ra. | Understanding the CMYK Color Mode The CMYK color mode is the color mode of paper and press. Printing presses sometimes referred to as a 4-color press convert an image s colors into percentages of CMYK Cyan Magenta Yellow and Black which eventually become the color plates on the press. One at a time the plates apply color to a sheet of paper and when all 4 colors have been applied the paper contains an image similar to the CMYK image created in Photoshop. The CMYK color mode can take an image from a computer monitor to a printed document. Before converting an image into the CMYK mode however it s important to understand that you will lose some color saturation during the conversion. The colors that will not print are defined as being out of gamut. To view the areas of an RGB image that will lose saturation values click the View menu and then click Gamut Warning. Photoshop will mask all the areas of the image that are out of gamut. Convert an Image to CMYK Color Open an image. Click the Image menu point to Mode and then click CMYK Color. Photoshop converts the image into the CMYK color mode. See Also See Using Curves and Color Adjustments on page 200 for more information on adjusting the color of an image. CMYK color mode Chapter 8 Understanding Colors and Channels 181 Understanding the Grayscale Color Mode The Grayscale color mode utilizes an 8-bit pixel 8 on off light switches to generate 1 black 1 white and 254 shades of gray. Although scanning and working on old black and white images might seem the obvious reason to use the Grayscale color mode the speed and power of Photoshop combined with faster computer systems has prompted most photo restorers to switch to the RGB color space because of its greater versatility and ability to generate millions of colors or shades of gray . Yet despite the move to RGB the Grayscale color mode is still used extensively with black and white images where file size is a consideration grayscale images are two-thirds smaller than .