Abstract: To a first organic liquid which has dissolved therein a flurocarbon polymer, e.g. 5 to 50% w/w e.g. PVDF, is added a second, compatible, non-solvent organic liquid in an amount (e.g. 1-50%) w/w such as to leave the polymer in solution. The mixed solution is applied to a leather or fabric substrate and heated e.g. at 60.degree. C. to 150.degree. C. for 2-15 minutes. Polymer deposits as the first liquid evaporates and pores form therein as the second liquid evaporates from the deposit. The anchored layer produced repels liquid water, but allows passage of water vapor.