Xerox C8 - DocuPrint Color Inkjet Printer, User Manual, Page: 444 / 458

430 Spire CXP8000 Color Server User Guide
Linework Linework graphics are characterized by sharply defined lines and very
clear transitions from one color to another. Linework is stored in the
computer as a series of geometric (vector) drawing instructions.
Metamerism
Metamerism occurs when two colors match under one light source,
but appear different under another light source. Those two colors are
called a metameric match. A metameric match might cause problems
when trying to match proofs to press-sheets under different lighting
conditions.
Midtones Density values of an image (original or reproduction) between the
highlights and the shadows. In the reproduction, midtones are
printed with dot areas between approximately 40% or 60%. See also
Highlights
and
Shadows
.
Misregistration A situation common during printing where one or more of the color
separations is slightly misaligned with regard to the others on press.
Misregistration shows up as white gaps or tinted overlaps at the
borders of color pairs. Colors containing such files are trapped to
compensate for this possibility. On Continous Tone images,
misregistration can lead to blurring. See also
Overprint
and
Trapping .
Moiré
An interference pattern caused by differences in halftone screen
angles or rulings. In process color printing, screen angles are selected
to minimize this pattern. If the angles are not correct, a pattern that
distracts the eye from the picture may be produced.
Newton's rings
Small concentric circles that can appear on film when two surfaces are
closed together but not in perfect contact.
OPI
Abbreviation of Open Prepress Interface. A prepress convention
established by Aldus Corps. OPI refers to tags or place holders in
source PostScript that point to TIFF or EPS images that have not been
embedded in the PostScript. These images reside in other locations
and are merged with the PostScript file when processed. Normally
used for performing high res/low res image substitution (alternative
to Creo APR).
Output resolution The number of laser dots per unit of linear measurement (millimeter,
inch etc.) on film or paper.