Halftones
Screen Frequency
Screen frequency or Lines Per Inch (LPI) is the number of lines of halftone dots that compose each inch of a halftone screen. The screen frequency determines the number of halftone dots used to represent gray levels in a given area.
The following formula shows the relationship between screen fre- quency, print resolution and gray levels. As the screen frequency increases, the number of gray levels decrease. If resolution is increased, the number of gray levels will also increase.
ngray levels = (resolution/screen frequency)2 + 1
You can change screen frequency by selecting the halftone type in the QMS 4060 configuration menu, through your application, or by using the PostScript setscreen operator.
The extra gray levels available through higher resolution provide a smoother shift from the darkest black to very light grays.
Screen Angle
A screen angle is the angle at which a halftone screen prints. The default screen angle for your QMS 4060 Print System is 45° at 300x300, and 600x600. This is the normal angle for black and white printers. Selecting advanced halftone types menu option will vary the screen angle. You can also change the screen angle through the PostScript setscreen operator.
Additional Technical Information |