You'll need:
1) Coffee filter or other absorbent material (paper towel and toilet paper won't work well, but special chromatography paper and maybe some special art paper could work... I recommend coffee filters though!)
2) Food coloring, markers, etc. (some type of pigment). Food pigments do not really work that well but you can try it.
3) An organic solvent (Choices: 70-100% isopropyl alcohol, ethyl acetate or acetone (fingernail polish remover at the drug store!), or even distilled spirits like vodka, rum or gin (as long as it's colorless).
