1.8 explain how information from chromatograms can be used to identify the composition of a mixture

1- Make chromatograms for all the unknown substances you want to identify
2- Make chromatograms of known substances for references (e.g. substances that you think might be in the ink)
3- Now compare the chromatograms to work out what dyes are in your unknown substance - spots on the unknown substance will match spots on the reference materials should the dyes be the same.