Konica Minolta bizhub PRO C6500P - Manual (Page 223)

Setting Parameters in the Job Parameters Window 215
Trapping is a solution that solves misregistration between color
separations in both offset and digital printing. This occurs no
matter the accuracy of the printing device, and results in white
lines around objects on top of a background (in a knock-out
procedure) and also between adjacent colors.
Protect small text is an option you may apply for small or complex
images, since thicker frames can decrease quality by hiding parts
of an image. Selecting this option will protect any text smaller or
equal to 12 pt by not framing it while applying the FAF algorithm.
Frame thickness refers to the thickness of trapping. The thicker the
frame, the less chance that white areas appear between images.
Overprint
Black overprint
This check box is selected by default. It ensures that black text
prints cleanly within a tint or picture area. The text appears in a
richer, deeper black, with the underlying CMY values equal to
those of the printed background.
PS overprint
This check box is selected by default, and ensures that the
overprint information that exists in the PostScript file is used. This
parameter also determines whether the DTP application PostScript
overprint settings are honored in the RIP.
Screening
¾ Select the required option. For CT images, use a dot option,
and for LW images, use a line option.
Screening converts CT (Continuous Tone) and LW (Line Work)
images into information (halftone dots) that can be printed. The
human eye “smooths out” this information, which seems visually
consistent with the original picture. Thus, the more lines per inch,
the more natural the image appears.
Screening is achieved by printing dots in numerous shapes or
lines in an evenly spaced pattern. The distance between the
screen dots or lines is fixed and determines the quality of the
image.