Paper chromatography? help please.?

The retention factor (Rf) is a ratio of how far the molecule/spot traveled relative to the total distance the solvent traveled. Measure from the origin line to the spot and from the origin line to the solvent front; then divide the first one by the second. (The units that you use to measure don't matter as long as all measurements are in the same units.) The value will be between zero and one. A value closer to zero means that the spot did not travel very far (closer to the origin), and a value closer to one means that the spot traveled further (closer to the solvent front).