Pigments for paper coating compositions

A paper coating composition comprising an aqueous suspension of an inorganic particulate material together with a hydrophilic binder, the binder being present in an amount of from about 4 percent to about 20 percent by weight based on the dry weight of the inorganic particulate material, wherein the inorganic particulate material comprises a material selected from kaolin, calcined kaolin, dolomite, ground natural calcium carbonate, precipitated calcium carbonate, calcium sulphate or talc and has a particle size distribution which when represented as a graph of percentage of weight of particles having an esd defined herein of given size versus particle esd expressed in microns and plotted on a logarithmic base 10 scale has the following features;

• (a) a first peak at a coarse particle size and a second peak at a finer particle size and a dip or trough between the first and second peaks;
• (b) the mean particle size x.sub.1 of the particles making up the first peak being in the range of from about 2 microns to about 4 microns;
• (c) the relationship between the said first and second peaks being such that the value of the mean particle size x.sub.2 of the particles making up the second peak is separated in the said particle size distribution graph from the value of x.sub.1 by at least 0.5;
• and (d) the minimum of the dip or trough is at a particle esd dimension of between 0.5 microns and 1.5 microns.