Following are the materials used in neon sign tubes for different colors.
For, Red – Neon gas.
Reddish orange – Neon gas + Argon gas.
Blue – Vapour of mercury.
Golden – Neon gas + Helium gas.
Green – mixture of Neon gas and mercury in yellow glass tube.
By depositing fluorescent powder on the inner surface of the tube varying colors in intensity can be made.
