Advertisement
|
Home
file:///C|/Documents%20and%20Settings/Miz%20B/My%20D...0UGTA/Nuvera%209.0%20UGTA_FINAL/English/psg_iq15.htm8/13/2008 2:37:13 PM
|
Resources
|
System Tour
About Halftones and Gray Levels
A halftoned image is a series of dots arranged in a patterned
grid of halftone cells, which yields the appearance of a complete
image.
Screen frequency refers to the number of rows of halftone cells.
The higher the screen frequency (in lines per inch) the sharper
the halftone image appears (see 33 and 75 LPI examples in the
figure).
Screen angle refers to the number of degrees from vertical at
which the halftone grid is set. The halftone is set at an angle
(usually 15, 45, or 75 degrees), to reduce moiré patterning. The
idea behind halftone screens is to make the dots as fine as
possible, so that the image itself is more visible that the dots.
The observer will tend to focus on the 'big picture' while ignoring
the microscopic halftone texture. When the dots are so fine that
the eye can not resolve them, the image appears to be
continuous.
TIP: If you have programmed and run a job, and
received unexpected results, ensure that the system-
wide settings are all set back to their defaults by clicking
<Clear All> or <Reset> in the user interface. Then
proceed to do job programming pertinent to your job.
Go to
Choosing the Best Halftone Setting
Production System Screen Frequency Demo Job.
|
Search
|
Problem Solving
Figures
for information on the
247 of 256
|
Index
About this Site
|
Maintenance
Advertisement
