A number of variations may include depositing, on a substrate comprising cellulose, an aqueous mixture comprising modified cellulose polymer molecules and organic acid molecules comprising at least two carboxyl acid groups; removing water from the mixture deposited on the substrate to provide a coating on the substrate; wherein the organic acid molecules have a melting point above ambient temperature, and wherein the organic acid molecules are cross-linkable with the modified cellulose polymer molecules and the cellulose at or above ambient temperatures.

A number of variations may include depositing, on a substrate comprising cellulose, an aqueous mixture comprising modified cellulose polymer molecules and organic acid molecules comprising at least two carboxyl acid groups; removing water from the mixture deposited on the substrate to provide a coating on the substrate; wherein the organic acid molecules have a melting point above ambient temperature, and wherein the organic acid molecules are cross-linkable with the modified cellulose polymer molecules and the cellulose at or above ambient temperatures.

The present invention provides an aqueous pigment dispersion including a pigment, an anionic group-containing organic polymer compound, and bio-nanofibers having an average diameter of 1 nm or more and 100 nm or less and an aspect ratio of 100 or more, and also provides an aqueous ink using the aqueous pigment dispersion. The bio-nanofibers are preferably cellulose nanofibers or chitosan nanofibers. The anionic group-containing organic polymer compound is preferably at least one selected from the group consisting of acrylic resins having anionic groups, polyurethane resins having anionic groups, and polysaccharide derivatives having anionic groups.

The present invention provides an aqueous pigment dispersion including a pigment, an anionic group-containing organic polymer compound, and bio-nanofibers having an average diameter of 1 nm or more and 100 nm or less and an aspect ratio of 100 or more, and also provides an aqueous ink using the aqueous pigment dispersion. The bio-nanofibers are preferably cellulose nanofibers or chitosan nanofibers. The anionic group-containing organic polymer compound is preferably at least one selected from the group consisting of acrylic resins having anionic groups, polyurethane resins having anionic groups, and polysaccharide derivatives having anionic groups.

A coating composition may include kaolin having a shape factor less than about 70 and calcium carbonate, wherein less than about 90% by weight and greater than about 60% by weight of particles of the calcium carbonate have an equivalent spherical diameter (esd) less than 2 microns. The coating composition may include a thickener present in an amount ranging from about 0.1% to about 0.9% by active dry weight of the composition. A coating composition may include kaolin having a shape factor less than about 70 and calcium carbonate having a mean particle size (d.sub.50) of at least about 2.4 microns and a steepness factor of at least about 30. The coating composition may be a paper basecoat composition or a paperboard basecoat composition. A paper or paperboard product may include the coating composition on at least one surface of the paper product or paperboard product.