On an indoor surface, any color of Alvas Matlay or Alvas Marlay is suitable. However, the surface should be shaded and kept out of direct sunlight as much as possible. Vinyl dance floors cannot be installed nor used in direct sunlight.
On an outdoor surface, because of the heat of the sun, only the white side up of the white/black Matlay floor may be used. The gray and black floor gets too hot in the sun and can cause burns, making it unsafe to use.
Keep in mind possible inclement weather, as this could cause safety concerns as well. Sweat, any kind of humidity or moisture can cause a slippery surface. If it gets wet, it must be dried off.