Paper chromatography of artificial food colourings, timelapse footage. Paper chromatography is a technique in which a substance is separated out into its constituent parts as it dissolves in a solvent and spreads along the paper. Different pigments in the colourings are carried a different distance by the solvent, as they travel at different rates. Five colourings were used here, from top to bottom: red, green, blue, yellow and black. The chromatography reveals that there are several separate pigments used to make up the different colours, each marked with a moving label. These are, from left to right, E122 Azorubine, or Carmoisine, E129 Allura Red, E104 Quinoline Yellow, E124 Ponceau 4R, E142 Green S and E133 Brilliant Blue FCF. The solvent was water and the run time was three hours.