A continuous inkjet method in which liquid passes through a nozzle, the liquid being jetted comprising one or more dispersed or particulate components and where the particle Peclet number, Pe, defined by Pe = 1.25  φ T · d eff 3  μ S kT  ρ   U 3 x is less than 500 and where the effective particle diameter, deff, is calculated as d eff = ( ∫ 0 ∞  d 3  φ  ( d )    d ∫ 0 ∞  φ  ( d )    d ) 1 / 3 where Φ(d) is the volume fraction of the particles or components of diameter d (m) and where ΦT is the total volume fraction of dispersed or particulate components, μS is the viscosity of the liquid without particles (Pa.s), ρ is the liquid density (kg/m3), U is the jet velocity (m/s), x is the length of the nozzle in the direction of flow (m), k is Boltzmann's constant (J/K) and T is temperature (K). The present invention limits the magnitude of flow induced noise generated by particulate components in the ink to maximise the efficiency of drop formation and to minimise adverse interactions with the nozzle.