colored compounds are easy to locate. And coloured compounds can observe using
normal visible light. The colorless compounds are observed using UV light. The
colourless compounds are located under UV light in two different wave lengths.
Under 254 nm wave length the background of the filter paper will be light
coloured and the spots will appear as dark spots. Fewer than 350 nm wave lengths
the background of the filter paper will be dark and different coloured spots
will be appeared.