The invention concerns a process to manufacture paper coatings containing at least one mineral matter, at least one binder and water, characterised in that at least one comb polymer obtained by grafting of a least one polyalkylene oxide function on to the polymer chain, where the said chain results from the polymerisation of a least one ethylenic unsaturated monomer, is introduced into the above-mentioned composition. The paper coatings thus obtained have increased water retention and reduced Brookfield viscosity compared to the same coatings containing a water-retaining thickening agent of the prior art.