Chromatography: For separating liquids by dissolving them in a solvent. The dyes that make up the ink differ in two important ways:
- How strongly they stick to the paper
- How soluble they are with the solvent
An example would be separating ink colours or plant dyes. A dot of the ink/dye would be drawn onto a piece of paper. It would then be left in water, which acts as a solvent. Because different colours have different solubility levels, some colours would travel up further on the paper.