A continuously variable screening tool is used to generate a unique texture pattern
for every color in a multicolor image. The continuously variable screening tool
allows a single colorant version of the image to be generated with less information
loss than typically suffered in the multicolor to single color transformation process.
The continuously variable screening tool is generated by blending patterns from
a set of reference screens. The reference screens are associated with selected
reference colors in, for example, a machine independent color space. A calculated
screen is generated through a weighted blend of reference screens located near
the arbitrary color in the machine independent color space. Typically, the weights
depend on the distance the arbitrary color is from each of the reference colors.
The screens consist of arrays of threshold values. Each threshold value is associated
with a dot position and an image pixel. Where a pixel value exceeds the associated
threshold value, provision is made to place a mark in the associated dot position.
An image processor operative to carry out the method comprises a continuously variable
screening tool generator. An embodiment of the image processor includes a reference
screen storage device and a screen blender.