Waterproof fabric and fabrication method thereof

A waterproof fabric fabricated by the textile substrate having interstices less than 1 mm wide being taut and coated on one side with a thin film of liquid synthetic material and the whole is treated to solidify said film, wherein said film consists of an acid solution containing between 20 percent and 30 percent of a polyamide by weight, and is applied to said textile substrate to a depth of at least 50 microns by spreading in liquid form, whereafter the action of the acid solution on said textile substrate is immediately neutralized and the polyamide of said solution is coagulated by running the coated fabric product through a base bath, and the fabric is thereupon washed in water and dewatered, wherein said coagulated film adjacent to said textile substrate has elongated pores extending transversely to said film, said pores open to said textile substrate, and said coagulated film adjacent its surface away from said fabric substrate has smaller, open ovoid pores communicating with both said surface and said elongated pores.