Nuance PDF Professional includes predefined conversion controls which specify
compression settings for color images, grayscale images, and monochrome
(black-and-white) images. Compression helps to make your PDF files smaller.
You can select the appropriate control from the drop-down list:
LossLess (level 100)
High Quality (level 75)
Medium Quality (level
50) (default for Standard Quality)
Low Quality (level 25)
Image Place Holder (level
5)
No Image (level 0)
Set level 0 to have pictures in the source document dropped from the
PDF. Select level 5 to have very low quality images, serving only as place-holders.
You can edit the settings for an existing control, add a new control,
or delete an existing control in the Compression Controls dialog box.
To display the Compression Control dialog box
Click the Advanced
button.
Highlight a conversion control in the list of conversion
controls and view or edit the settings as needed.
Modify the Auto-setting
Move the slider from a pre-set value to a value of your choice. This
affects the compression for texts, line art and images in your documents.
Use Custom Settings
Select a compression method for any color, grayscale, or monochrome
images in your document.
For color and grayscale images,
you can choose from a range of qualities of JPEG
and ZIP formats, from High to
Low.
Which method is best depends on the kind of images in your particular
document. Some compression techniques do not lose any detail in the original:
these methods are called “lossless.” Lossless methods do not save as much
disk space as the other kind of compression, which is called “lossy.”
Files compressed using lossy methods can be much smaller than files using
lossless methods.
For example, JPEG is best for images requiring a smooth transition from
one color or shade to another while ZIP works well for sharper changes.
For best results, you might want to try different compression settings
for different documents.
The default value for each of the predefined conversion controls allows
the print driver to choose the best method based on the nature of the
image.
For monochrome images, you can
choose from ZIP, CCITT
Group and Run Length encoding.
CCITT (International Coordinating Committee for Telephony and Telegraphy)
compression method works best for black-and-white images made by paint
programs and 1-bit scanned images.
Run Length produces the best
results for images that contain large areas of solid white or black.
ReSample
Select or clear the ReSample
setting. Resampling changes the pixel dimensions (and thus the display
size) of an image.
If you choose to ReSample, specify either DownSample
or SubSample from the pull-down
menu. The default setting is DownSample.
Downsampling decreases the number of pixels in the image. Each pixel
it places has the average value of all the pixels it replaces.
Subsampling chooses a pixel in the center of the sample area and replaces
the entire area with that pixel at the specified resolution.
Resolution
If you resample images, you can specify a resolution for downsampling
or subsampling.
Factory Settings
The Factory Settings button
automatically returns compression settings to their original values.
New
Click the New button to create
a new conversion control.
Delete
The Delete button removes the
currently selected conversion control.
Default
This returns supplied controls to default values and removes user-defined
controls.
Note
If you set MRC compression,
you should set lossless compression here.
