Traditional column chromatographic purification of a reaction mixture.
In organic chemistry we prepare compounds that could be usually black/brown/yellow depending on impurities and in pure form colorless. It’s a quite rare case that any color that appears in the reaction mixture is a good sign on anything. In this case the orangish spot on the column is luckily a product that was planned and it contains diazo groups that are reason of the color.
More about chromatography: http://labphoto.tumblr.com/tagged/chromatography