Abstract: At least one certain primary or secondary color is established that receives special treatment for at least one printing medium. Such treatment may include (1) using more than two drops of primaries per pixel for binary printing of a particular secondary; or (2) binary-printing the chromatic primary or secondary--but not other hues--after rendition, by use of a "superpixel"; or (3) application of, in effect, a nonintegral number, greater than one, of ink drops per pixel; or (4) combinations of these treatments. As an example of the first of these treatments--using inks optimized for plain paper at one drop of ink for primaries and two (one of each of two primaries) for secondaries--red is printed on transparency film as one drop of yellow ink and two of magenta in each pixel. As to the second treatment, the superpixel is preferably a group of pixels (e.g., a two-by-two array) including the target pixel, in which group each pixel is inked and at least one pixel receives at least two drops of ink.

Abstract: Aqueous ink compositions containing anti-curl agents substantially reduce or eliminate paper curl in plain-paper printed elements without adversely effecting storage stability, decap properties or print quality, and thus eliminate the need for expensive and bulky mechanical curl-arresting devices or special curl-resistant substrates. Printing the inks on plain-paper substrates is the sole step in a process for reducing paper curl in plain-paper printed elements.