paper chromatography

what substance are you testing?

if the compounds are already colored (food colorings, pigments, chlorophylls... ), then that's fine.
there're some methods to visualize the separated substances.
for example, the papaer can be illuminated with UV light. some compounds, especially aromatic ones, can produce fluorescence.

for reducing sugars, anilinium hydrogen-phalate solution can be sprayed on the paper, followed by incubation at higher temperature.
the sugar will undergo condensation with the ions, producing a highly-conjugated compound. it can fluorescent under UV.

for most of the amino acids, ninhydrin can be sprayed on the paper, followed by heating and drying. the amino acid will react to give pink-violet color even under visible light.