Browse Prior Art Database

Test Pattern for Determining Print Dot Diameters

IP.com Disclosure Number: IPCOM000101134D
Original Publication Date: 1990-Jul-01
Included in the Prior Art Database: 2005-Mar-16
Document File: 2 page(s) / 46K

Publishing Venue

IBM

Related People

Maier, U: AUTHOR [+2]

Abstract

In high-quality image setters, small variations in the dot size adversely affect the halftone quality with respect to number and linearity of grey levels. Such dot size variations, depending on the media and print parameters used, may be corrected with an accuracy of 1 mm by the method described below using visual means.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 91% of the total text.

Test Pattern for Determining Print Dot Diameters

       In high-quality image setters, small variations in the
dot size adversely affect the halftone quality with respect to number
and linearity of grey levels.  Such dot size variations, depending on
the media and print parameters used, may be corrected with an
accuracy of 1 mm by the method described below using visual means.

      This method concerns the generation of a test structure
consisting of two symmetrical grey wedges.  The test structure is
subdivided into an inner structure of finely distributed dots and an
outer structure of coarse clusters. With finely distributed dots, the
grey value increases proportional to the dot area, whereas with
clusters only the peripheral dots increase non-linearly.  In other
words, for finely distributed dots, the grey value increases much
faster than for clusters.  At too small a dot diameter, the lightness
of the inner structure increases the more the dot diameter differs
from the desired one.  For the desired dot diameter (operating
point), the density of the inner and the outer structure is
identical. At too large a dot diameter, the inner structure is too
dark, the more so the larger the dot size is.

      At the operating point, both grey wedges are identical and
linear.  At too small a dot size, the wedges are too light compared
with the average dark field.  Too large a dot size, on the other
hand, is indicated by saturation in the center on either side...