A digital-printing substrate and method of improving adhesion of a substrate to an liquid electrophotographic (LEP) ink in LEP printing both employ a composite coating. The composite coating includes from 4.5% to 9.5% by weight of a mineral pigment and from 0.5% to 2% by weight of an organic binder uniformly dispersed in water. The mineral pigment has a particle size less than 1 micron. The organic binder comprises a hydroxylated polymer having an average molecular weight greater than 50,000. A weight percentage of hydroxyl groups in the hydroxylated polymer is equal to or greater than a weight percentage of acidic groups in an LEP ink. The composite coating enhances adhesion of the LEP ink to the substrate comprising the composite coating dried on a surface of the substrate.