Why do old photos turn yellow?
Show answer & explanation
Answer: Chemical reactions with air
Chemical reactions with air ✓ — Correct! Paper contains lignin that oxidizes when exposed to air and light, turning yellow-brown. Acids in paper also break it down over time. That's why archival photos use acid-free paper and are stored in darkness!
Ink fades leaving yellow — Wrong. The yellow isn't hidden underneath. Paper's chemical breakdown creates the yellow color.
Photos were always yellowish — Wrong. Fresh photos weren't yellow. Chemical degradation over time causes the color change.