An imaging element comprising a light-sensitive imaging layer and a polyester film support having coated thereon greater than 0.17 gm/m.sup.2 of a layer of a self-crosslinking polyurethane derived from an isocyanate terminated prepolymer extended with an aliphatic polyamine and end-capped with N-methylol hydrazide groups, the prepolymer being derived from (a) a diisocyanate, and (b) a polyester polyol and having pendant water dispersing, carboxylic salt groups on the polymer chain.