Why is denim blue? – Ruthenium Zone

Question: Why is denim blue?
- Keywords:
  blue,
  colour,
  denim,
  material
Asked by luvinscience1202 to Ed, Hayley, Jason, Nathan, Sophie on 18 Mar 2013.
- Hayley Evers-King answered on 18 Mar 2013:
  
  Denim is dyed blue. It’s made from cotton, which is usually white. Something I learned just now when I was looking up the history of it is that it’s named after a place called: “Serge de Nîmes” which was shorted to just de Nim (denim)!

Question: Why is denim blue?