HP qms 1660e ユーザーズマニュアル
Gamma
Correction,
Halftones, and
Screens
QMS 1660E Print System Reference
5-6
The following illustration shows the relationship between screen fre-
quency, gray levels, and print resolution. As the screen frequency
increases, the number of gray levels decreases.
quency, gray levels, and print resolution. As the screen frequency
increases, the number of gray levels decreases.
The number of gray levels that your printer can produce depends on
the screen frequency and the print resolution. The default value for
screen frequency using 600 dpi is 71 lpi. This typically allows 73 dif-
ferent levels of gray. The default value for screen frequency using 300
dpi is 53 lpi. This typically allows 33 different levels of gray. You can
change screen frequency through your application or by using the
PostScript setscreen operator.
the screen frequency and the print resolution. The default value for
screen frequency using 600 dpi is 71 lpi. This typically allows 73 dif-
ferent levels of gray. The default value for screen frequency using 300
dpi is 53 lpi. This typically allows 33 different levels of gray. You can
change screen frequency 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 while higher
resolution provides sharper image outlines.
smoother shift from the darkest black to very light grays while higher
resolution provides sharper image outlines.
Screen Angle
A screen angle is the angle at which a halftone screen prints. The
default screen angle for your QMS 1660 Print System is 45° at
300x300 and 600x600 dpi. This is the normal angle for black and
white printers. At 1200x600 dpi the screen angle is 26.56°.
default screen angle for your QMS 1660 Print System is 45° at
300x300 and 600x600 dpi. This is the normal angle for black and
white printers. At 1200x600 dpi the screen angle is 26.56°.
You can change the screen angle through the PostScript setscreen
operator.
operator.
300x300 dpi
600x600 dpi
42
53
71
106
Screen Frequency (lpi)
Gray Levels
250
250
200
150
100
50
0
51
33
19
9
201
129
73
33