Chromatography can be used to seperate out dyes in a sample of ink.

  1. Spots of dye are dropped onto a baseline on a square of filter paper.
  2. The sheet is rolled up and placed in a beaker containing shallow solvent.
  3. The solvent seeps up the paper, taking the dyes with it.
  4. Each different dye in the ink samples will form a distinct spot on the paper.
  5. It is now possible to compare the unknown ink to known dyes.