A metallic nanoparticle dispersion comprising metallic nanoparticles characterized in that the dispersion comprises less than 50 µmol/g metal of an inorganic acid or a compound capable of generating such an acid during curing of a metallic layer or pattern formed from the dispersion. The presence of such small amounts an inorganic acid increases the conductivity of metallic layers or patterns formed from the metallic nanoparticle dispersions at moderate curing conditions.