 Neon lights were named for neon, a noble gas which gives off a popular orange light, but other gases and chemicals are used to produce other colors, such as hydrogen (red), helium (yellow), carbon dioxide (white), and mercury (blue).Neon tubes can be fabricated in curving artistic shapes, to form letters or pictures.They are mainly used to make dramatic, multicolored glowing signage for advertising, called neon signs, which were popular from the 1920s to the 1950s.