K/S values are shown in Fig. 4. Higher K/S values indicate higher dyeing yield and deeper colours. A lthough K/S values varied depending on mordant concentration and type, mordanting with ferrous salt yielded relatively high K/S values and also they were independent from concentration of mordant. Concentration of mordant did not affect the colour strength of dyeings in the case of mordanting with Al and Cr. However big increases of colour strength values were ob-served in the case of Cu and Pb mordants.