a method for producing a pattern of hydrophilic and hydrophobic regions on a printing form is presented which , in a first , essentially unpatterned state , features a polymer material containing imide groups , for example , polybenzene diimide or polyamide imide . the method includes a chemical treatment of the surface with an oxidizing agent subsequent in time to a locally selective exposure with uv light . optionally , the locally selective exposure can be preceded by a large - area chemical treatment of the surface with a strong base . the printing form can be restored to the first state by a large - area chemical treatment of the surface with a strong acid . the patterned printing form is suitable for use in offset printing .