What is the Color of the Spirit Level or Buble Level Vial?
Why is a spirit level vial green? The color of a spirit level vial is traditionally a range of yellow-green because, quite simply, this is the central range of color most visible to the human eye in all lighting conditions. On either side of the visible light spectrum is purple-blue on one side moving toward non-visible ultraviolet light and orange-red on the other moving toward the non-visible infrared light. Types of Level Vials: Barrel Vial vs. Block Vial Spirit level vials can take two forms: a barrel vial and a block vial. The barrel vial is just that, a barrel. But note a barrel is not a cylinder, in which the diameter of the vial is the same from top to bottom. Instead, the barrel vial bulges in the center, giving the bubble a place to rest. The barrel vial body was originally (and in some cases still is) made of glass but today they are mostly acrylic. Benefits of acrylic spirit vials over glass vials is durability (they don’t break as easily) and visibility (the don’t scratch
