Paper Chromatography

In one of the past science lessons, I learnt about paper chromatography. We used it to seperate the blue colour of a pen to see what colours makes up its colour. We had a dot on a filter paper and put it in a test tube of ethanol. Lastly, we waited. We waited until the colour was broken up and observed the colours present at the end. The further the colour is from the original blue colour, the more loosely attached it is to the filter paper, and thus the closer it is to the blue colour, the more strongly it attaches itself to the filter paper. There are also other forms of chromatography like gas chromatography which separates different gases.