Why does paper turn yellow over time?
Paper's Slow Return
Why does paper turn yellow over time?
You pull an old book off the shelf, and the pages have turned the color of butter. Or maybe you find a newspaper from your grandparents' attic, now more brown than white. What happened? The paper didn't go bad like milk in the fridge — it went through a slower, sneakier change.
Paper is made from trees, and trees are held together by a molecule called lignin. Think of lignin as the glue that keeps wood stiff and strong — it's what makes a tree trunk stand tall instead of flopping over like a wet noodle. When paper is made, most of the lignin gets washed away, but some always stays behind, hiding between the fibers.
