from 1 to 50 by weight of the coating titanium oxide is the most preferred pigment but other inorganic oxides and even carbonates can be used it is desirable that the paper not exhibit a variation in optical density between the marked or unmarked areas on the backside when there is backlighting on the paper base there should be an optical density variation of less than 0 2 when viewed in the transmission mode with high intensity room lighting preferably there should be an optical density variation of less than 0 1 when so viewed the temperature of the resin during extrusion is usually between 90 and 200 u00b0 c the temperature of the chill roll is usually between 0 and 40 u00b0 c the speed of the paper through the operation is usually between 100 and 500 ft min 30 to 150 m min the polymer used in the coating operation may be substantially any transparent preferably colorless thermoplastic resin such as polyolefins nylons polyesters polyvinyl resin and the like polyolefins such as polyethylene polypropylene and mixtures blends and copolymers thereof are most preferred these and other aspects of the invention will be understood from a reading of the following non limiting example a roll of commercially available white primed paper stock is fed by rollers towards an extrusion head at about 91 meters per minute a composition comprising 85 percent by weight polyethylene and 15 percent by weight titania is extruded at 120 u00b0 c onto the paper at a coating.