8.5

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Grayscale images group
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Compression: Select the compression to use for the grayscale images. Flate is a lossless
compression method, so no data is lost in the process. It works well on images with large areas
of single shades or repeating patterns, such as screen shots and simple images created with
paint or drawing programs. JPEG removes image data and may reduce image quality, but may
be suitable for continuous-tone photographs containing more detail than can be reproduced
onscreen or in print. Since JPEG eliminates data, it can achieve much smaller file sizes than
Flate compression. Select Auto to let the application choose the best compression method
automatically. Note that configurations that were created with an earlier version of PReS
Workflow and that included tasks set not to use any compression will by default be set to use the
Flate compression method.
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Downsampling: Select the down sampling option. Down sampling reduces image size by
breaking images down into small areas in which multiple pixels are replaced by single pixels.
The Grayscale resolution you enter in the following box is used to control the down sampling
process. Select None to prevent grayscale down sampling. Select Average to average pixel
shades in each sample area and to replace the entire area with a pixel of the average shade.
Select Subsample to use a pixel in the center of the sample area and replace the entire area with
that pixel value. This method is significantly faster, but results in images that are less smooth.
Select Bicubic to use a weighted average to determine pixel shades. This method is the slowest
but most precise and results in the smoothest tonal gradations.
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Resolution: Select the resolution to use for grayscale images. Note that this setting has an
impact on the grayscale down sampling process.
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Color images group
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Compression: Select the compression to use for the color images. Flate is a lossless
compression method, so no data is lost in the process. It works well on images with large areas
of single shades or repeating patterns, such as screen shots and simple images created with
paint or drawing programs. JPEG removes image data and may reduce image quality, but may
be suitable for continuous-tone photographs containing more detail than can be reproduced
onscreen or in print. Since JPEG eliminates data, it can achieve much smaller file sizes than
Flate compression. Select Auto to let the application choose the best compression method
automatically. Note that configurations that were created with an earlier version of PReS
Workflow and that included tasks set not to use any compression will by default be set to use the
Flate compression method.
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Downsampling: Select the down sampling option. Down sampling reduces image size by
breaking images down into small areas in which multiple pixels are replaced by single pixels.