Looking at Vermilion - the Colour of Money
At the time that these Frescoes in a Pompeian Villa were painted, Cinnabar or Vermilion Red was one of the most expensive pigments on the market and so, by using it to so abundantly to cover great swathes of wall, the owner was making sure everyone knew they had money.
It certainly would not have been a colour that most could afford to use so ostentatiously for the raw material only came from one region in Spain. It then had to be shipped to Rome for processing and this had to be done by experts who could purify and grind it into the perfect fineness to achieve its bright red and not the black that it could turn into in the wrong hands. Therefore, it was a beautiful rich red for very rich people.