Chemical mordants are potassium aluminium sulfate-12-water (Kal(SO4) 2·12H2O), copper (II) sulphate pentahydrate (CuSO4·5H2O), iron (II)sulphate heptahydrate (FeSO4·7H2O), sodium sulphate decahydrate (NaSO4·10H2O), potassium
dichromate (K2Cr2O7), tin (II) chloride (SnCl2),potassium bitartrate (KHC4H4O6) and some others