The ink that we use has water as the solvent and the dye is soluble in it. As the water rises on the filter paper it takes along with it the dye particles. Usually, a dye is a mixture of two or more colours. The coloured component that is more soluble in water, rises
faster and in this way the colours get separated.
This process of separation of components of a mixture is known as chromatography. Kroma in Greek means colour. This technique was first used for separation of colours, so his name was given. Chromatography is the technique used for separation of those solutes that dissolve in the same solvent.
With the advancement in technology, newer techniques of chromatography have been developed. You will study about chromatography in higher classes.
Application To separate
• colours in a dye
• pigments from natural colours
• drugs from blood.