Xerox DocuColor 250 Online Help Manual page 140

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dot pattern. The line screen halftone makes seeing
artifacts and patterns in a large halftone more likely
compared to a dot screen. However, when two straight
lines adjoining halftone areas meet, then the linear
nature of the screen avoids the jagged border areas
that are more often found in a dot screen pattern.
– Stochastic Screens: Stochastic screening uses
randomly placed dots instead of the traditional halftone
dots aligned along designated screen angles. The
concept of stochastic screening is that dots placed
randomly will not cause moire patterns. However,
completely random positioning does not work well. The
stochastic screen prevents screening interference
patterns, but it can cause graininess and other visual
artifacts. Therefore, stochastic screening as
implemented by your Xerox color printer uses a
complex algorithm to determine the optimum
placement of dots in order to appear random while
reducing graininess. This "random" arrangement of
dots means there is no "direction" to the screen; and
therefore no screen angle exists. The variable spacing
of the dots means there is no fixed spacing, and
therefore there is no screen frequency. So, without
frequency or angle, there is no possibility of moire
between the four process-color screens, or even of
moire from patterns within an image.
Setting the Halftone Screen
To set the halftone screen within Queue Manager:
1. Open Queue Manager.
2. Double-click the desired queue.
3. Select the Image Quality tab.
4. Select the Halftone FAB.
5. From the Halftone pull-down menu, select the desired setting
according to your system. For most jobs, you will want to
accept the default, "System Specified" setting.
6. If desired, enter halftone information in the supplied text field.
7. Select [OK] to accept the changes and exit the Queue
Properties tabset, or [Apply] to commit changes without exiting
the dialog. If you do not wish to retain your changes, select
[Cancel] to exit without saving changes.
Setting Image Resample, or Interpolation, options
To select an interpolation method, perform the following steps:
1. Open the Queue Manager.
2. Double-click the desired queue.
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