A method of coloring a cellulosic material which includes a) dispersing
pulped cellulosic material into water; and b) coloring the pulped
cellulosic material by adding a cationic dispersion to the water, where
the dispersion includes: (i) at least one pigment; (ii) water; and (iii)
at least one acid salt of a styrene maleimide resin in an amount
effective to disperse the pigment. The cationic dispersion may be
prepared by (i) mixing, at 500 to 10,000 rpm, at least one pigment;
water; and either (a) at least one acid salt of a styrene maleimide imide
resin or (b) at least one styrene maleimide imide resin in combination
with at least one weak acid, thereby forming a dispersion premix; (ii)
milling the dispersion premix in a mixer filled with ceramic, metal or
glass beads for a period of time sufficient to reduce pigment
agglomerates to primary particles, thereby forming a nonstandarized
dispersion; and (iii) standardizing the dispersion against a color
standard by adding water. The resulting cationic dispersion can be used
to color cellulosic materials such as cotton and paper.