Operation Manual

75
USING ACROBAT X STANDARD
Creating PDFs
Last updated 10/11/2011
• Convert All Colors To sRGB (or Convert Everything To CalRGB) Calibrates color, making it device-independent.
Converts CMYK and RGB images to sRGB in PDFs compatible with Acrobat 4.0 (PDF 1.3) or later. Converts CMYK
and RGB images to calibrated RGB (CalRGB) in Acrobat 3.0 (PDF 1.2) compatible PDFs. Recommended for PDFs that
will be used on-screen or with low-resolution printers.
• Convert All Colors To CMYK Converts color spaces to DeviceGray or DeviceCMYK according to the options
specified in the Working Spaces menu. All Working Spaces must be specified.
Document Rendering Intent Choose a method to map colors between color spaces. The result of any particular
method depends on the profiles of the color spaces. For example, some profiles produce identical results with different
methods.
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.