Optimal sharpening refers to the scaled end format of an image contained in the printing data. In the following section, it is assumed that the processing of high resolution RGB images, their placement in the layout program, the creation of PDF data and the application of ZePrA is a continuous workflow within the same company.
In-house RGB workflows provide the option to work with high-resolution originals RGB images in the layout program and then create a PDF/X-3 or PDF/X-4 file that also contains the high-resolution RGB images. Color management, downsampling to the final resolution and sharpening for the PDF file are performed in ZePrA. After downsampling of RGB images to the final resolution and color conversion to CMYK, use stronger sharpening in ZePrA than normally used on pre-sharpened CMYK images.
Procedure: Select Define Configurations/Sharpening/Preset strong sharpening of RGB and Gray images. For documents that contain mixed image data set of RGB images and presharpened CMYK images, you should restrict the sharpening in ZePrA to RGB images.
Note: To sharpen all RGB images in ZePrA, do not perform any transparency reduction in the layout program, for optimum results sharpen the images in ZePrA.
Enabling transparency reduction in the layout software results in converting RGB data to CMYK if the RGB image in the layout program is adjacent to transparent objects. During generation of PDF/X-3 files, transparency reduction is mandatory, while in PDF/X-4 files, transparencies are explicitly allowed.