Abstract: To obtain optical effects, particularly dye pattern effects, a treatment is proposed for a web of material or a number of webs of material guided side by side in the nip between treatment rollers, more particularly a web of material impregnated with or containing dye or other finishes, wherein the treatment pressure is set differently in individual longitudinal portions of the nip or is set intermittently, so that the web of material is exposed to different treatment pressures at different points, with the result that, in particular, the dye or other finish is forced out of the parts of the web of material subjected to the greatest pressure, and into those parts subjected to least pressure. An apparatus is proposed for carrying out this treatment, wherein one of the treatment rollers which form the nip is a deflection adjustment roller and comprises support members which are associated with controllable pressure regulators for regulating the pressure in the support members.