In the two-sided coating of a web by feeding the web through the nip of a pair of pressing rolls onto which the coating substance is metered, the amount of the coating substance applied to each pressing roll is measured by infrared absorption and the relative coating quantities RW.sub.o onto the upper side and RW.sub.u to the underside are calculated by the relationsRW.sub.o =M2.sub.o /(M2.sub.o +M2.sub.u) andRW.sub.u =M2.sub.u /(M2.sub.o +M2.sub.u); andwhere M2.sub.o represents an infrared absorption measurement of the coating on the roll applying the coating to the upper side and M2u represents the absorption measurement of the coating on the roll applying the substance to the underside of the web.