Abstract: A surface-treated plastic film having a surface coating layer formed on at least one surface of a plastic film, which has a spreading index of aqueous and alcohol inks of 1.0-1.2, respectively, at the surface coating layer side thereof, and an ink jet recording material. The surface-treated plastic film of the present invention having respective spreading indices of aqueous and alcohol inks of 1.0-1.2 allows less spreading of the aqueous ink of ballpoint pens, is superior in writability and offset printability, and is extremely useful as a synthetic paper. In addition, the use of such surface-treated plastic film enables production of an ink jet recording material permitting high grade recording.

Abstract: A lithographic plate includes a substrate made of a polyester film having a light transmittance of 50% or less, a bending angle in the range of 30.degree. to 90.degree., and a rupture strength after being bent of 8 kg/mm.sup.2 or more. Alternatively, a lithographic plate includes a substrate made of a polymer film containing a polyester and a thermoplastic resin incompatible with the polyester, wherein the polymer film is oriented along at least one axis and has minute cavities formed by the orientation, and the density of the film is in the range of 1.05 g/cm.sup.3 to 1.3 g/cm.sup.3.

Abstract: A lithographic plate includes a substrate made of a polyester film having a light transmittance of 50% or less, a bending angle in the range of 30.degree. to 90.degree., and a rupture strength after being bent of 8 kg/mm.sup.2 or more. Alternatively, a lithographic plate includes a substrate made of a polymer film containing a polyester and a thermoplastic resin incompatible with the polyester, wherein the polymer film is oriented along at least one axis and has minute cavities formed by the orientation, and the density of the film is in the range of 1.05 g/cm.sup.3 to 1.3 g/cm.sup.3.