methyl read

Methyl red, an acid-base indicator.
I thought it should be red in an acid and yellow in a base.
However, the color looks yellow to orange in both diluted and concentrated sulfuric acid and pink to red in ammonium and sodium hydroxide.
I was confused. Is it the problem of the methyl red? Or it's because of chungyuan festival (ghost festival).


ref: http://chemistry.about.com/library/weekly/aa112201a.htm
http://www.youtube.com/watch?v=MrwOw6GKZMw