We are binding books for a client with pvc (black) coated cover (purchased by us). We tried silver foiling the logo on cover. Cover is plain semi gloss without any texture. However, the logos approximately 12mm x 12mm patch (reverse) cannot be foiled. It leaves several unfoiled spots. We have used copper plate blocks/dies. Used foils from kurz, Astral. Used letterpress type platen, and pneumatic press without any success. My foiling guy is suspecting covering material since foiling comes ok on paper and bopp laminated paper. Having said so are there any suggestions from anyone since time is limited and we have already bought cover material? Any ways to reduce surface tension of cover with some chemical or primer. Covering material is not corona treated. We already tried aqueous coating. Help will be highly appreciated.