Hey Friends! Today we are going to talk on How the old
newspapers and books turn yellow? The paper is made using pulp from wood which consists of Lignin and cellulose. Cellulose is the most abundant organic material in nature and Lignin is a substance which makes the wood stronger and harder. Both of these substances react with the sunlight and the oxygen present in the atmosphere. This reaction is known as oxidation which
causes changes in their structure and the paper turns yellow. Paper made from lignin are cheaper and they are used in newspapers. Lignin is more prone to the oxidation reaction than the cellulose. That is why the newspaper turns yellow faster than the paper of notebook. The Lignin is removed from the notebook paper by treating them with bleaching agents. Less amount of Lignin leads to slow yellowing of the page. But the prolonged exposure of paper to oxygen tend to undo the bleaching effect and turns it yellow too. So if you don’t want yellowing, use the Acid-free paper.