Chromatography is a technique that is used by scientists to separate mixtures. A mixture is placed on paper and a liquid is added. As the liquid travels through the paper, it acts as a solvent and dissolves everything in the mixture, so the mixture begins to travel with the liquid.
The various components of a mixture all have different properties, so they will travel at different speeds and separate. For example, if we do paper chromatography with black ink, we will observe a separation of the colors that make up the black color! What pigments (colors) do you think might be found in black ink? Depending on what brand pen you use will have different colors. Ours had purple.