Paper chromatography of artificial food colourings, timelapse footage. - Bildbanksvideo

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