Note: In some cases, the above software can produce a low-resolution image that
has a different file extension than the original high-resolution image. When
PostScript input files contain low-resolution images that have different file
extensions than the high-resolution images, Prinergy can replace the low-
resolution image with the high-resolution image as long as both files are in the
same folder.
About optimizing images
Optimizing is a function of the refiner that allows Prinergy to effectively
handle high-resolution images in the PDF workflow. Images are
downsampled according to specifications in the refine process
template and cropped automatically, so only the necessary resolution
and image portions are stored.
Downsampling
Sometimes the resolution specified for a contone image in the desktop
publishing software is greater than is needed, even for high-quality
color work. The additional resolution does not enhance the quality of
the image, but does make files larger. Downsampling stores the image
at a more appropriate resolution. An accepted rule of thumb is to set
downsampling to a ppi (pixels per inch) value that is twice the final
printed line screen or lpi (lines per inch). This is set in the
Optimize
section of the refine process template.
Image cropping
When an image is included in a file, but the whole image is not
required, the file size is larger than necessary. Image cropping removes
all image information that is not visible, except for a small border
around the visible image. This happens automatically during the refine
process when converting PostScript to PDF.
In the example below, the entire image was stored in the input file. The
area within the rectangle is the visible portion. Optimizing discards
almost all of the non-visible portions of the image (a border of 1 pixel
outside the bounding box is retained).
About optimizing images
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