Adobe 22020737 Acrobat X Pro Manual - Page 92

USING ACROBAT X PRO 86 Creating PDFs Acrobat shares four rendering intents (Perceptual, Saturation, Relative Colorimetric, and Absolute Colorimetric) with other Creative Suite applications. Acrobat also includes a rendering intent called Preserve, which indicates that the intent is specified in the output device rather than in the PDF. In many output devices, Relative Colorimetric is the default intent. Note: In all cases, intents may be ignored or overridden by color management operations that occur subsequent to the creation of the PDF file. Working Spaces For all Color Management Policies values other than Leave Color Unchanged, choose a working space to specify which ICC profiles are used for defining and calibrating the grayscale, RGB, and CMYK color spaces in distilled PDFs. • Gray Choose a profile to define the color space of all grayscale images in files. The default ICC profile for gray images is Adobe Gray - 20% Dot Gain. Choose None to prevent grayscale images from being converted. • RGB Choose a profile to define the color space of all RGB images in files. The default, sRGB IEC61966-2.1, is recognized by many output devices. Choose None to prevent RGB images from being converted. • CMYK Choose a profile to define the color space of all CMYK images in files. The default is U.S. Web Coated (SWOP) v2. Choose None to prevent CMYK images from being converted. Note: Choosing None for all three working spaces has the same effect as selecting the option Leave Color Unchanged. You can add ICC profiles (such as ones provided by your print service bureau) by placing them in the ICCProfiles folder in the Common folder, the Windows\System\Color folder (Windows), or the System Folder/ColorSync folder (Mac OS). Preserve CMYK Values For Calibrated CMYK Color Spaces When selected, device-independent CMYK values are treated as device-dependent (DeviceCMYK) values, device-independent color spaces are discarded, and PDF/X-1a files use the Convert All Colors To CMYK value. When deselected, device-independent color spaces convert to CMYK, provided that Color Management Policies is set to Convert All Colors To CMYK. Preserve Under Color Removal And Black Generation Retains these settings if they exist in the PostScript file. Black generation calculates the amount of black to use when reproducing a color. Undercolor removal (UCR) reduces cyan, magenta, and yellow to compensate for black generation. Because UCR uses less ink, it's suitable for uncoated stock. When Transfer Functions Are Found Specifies how to handle transfer functions in PDFs. Transfer functions are used for artistic effect and to correct for the characteristics of a specific output device. • Remove Deletes any applied transfer functions. Applied transfer functions should be removed, unless the PDF is to be output to the same device that the source PostScript file was created for. • Preserve Retains the transfer functions traditionally used to compensate for dot gain or dot loss that may occur when an image is transferred to film. Dot gain or loss occurs when the ink dots that make up a printed image are larger or smaller than in the halftone screen. • Apply Applies the transfer function, changing the colors in the file but doesn't keep it. This method is useful for creating color effects in a file. Preserve Halftone Information Retains any halftone information in files. Halftone information is intended for use with a particular output device. Last updated 10/11/2011