The principle involved in paper chromatography is

Paper chromatography has two phases, stationary phase and mobile phase. Stationary phase corresponds to the cellulose filter paper which holds water molecules in them, while mobile phase corresponds to the solvent. When the paper with the sample is dipped in the solvent such that the sample does not touch the solvent directly. Slowly the solvent moves upwards due to capillary action of pose in cellulose paper. As the solvent moves through the sample the components get separated depending on their affinity towards water and solvent. Those with more affinity towards solvent move forward faster thus getting parted. As the components get parted the principle involved is partition.