How Neon Signs Are Drawn, Bent and Lit

Every neon sign starts as a drawing, and the drawing has to obey the glass.

A sign-maker traces the design full size, bends tubing over a flame to match it, then pumps out the air and fills the tube with gas. The gas, and sometimes a coating inside the glass, decides the colour you see.

Updated 16 October 2026 · 4 sources

One continuous line
Gas sets the colour
Black paint makes gaps
Simple rules, bright results

Pick a colour

THE SHORT ANSWER

Drawn, bent,
filled and lit.

A neon sign is a sealed glass tube with gas inside.
Shape, gas and coating are all decided at the drawing stage.

DESIGN

The drawing must be one continuous line

The maker traces the shape onto paper first. Letter forms must be continuous so the gas can flow evenly from one end of the tube to the other.

Design rules

TRUE NEON

Real neon glows red-orange

Neon is a colourless gas that shows a red-orange glow when an electrical discharge passes through it. Other colours use other gases or coloured glass.

Pick a colour

OTHER COLOURS

Blues and greens are a two-step trick

Argon starts the arc, mercury vapour then gives off ultraviolet light, and a phosphor coating inside the tube turns it into blue, green or yellow.

Where it began

Glass tubes glowing blue, green and pink in looping abstract lines on a dark background — AI-generated image, not a photograph of a real person or place.

FOUR RULES FOR A NEON DESIGN

Drawing for glass,
not for paper.

Whether you sketch by hand or on a computer, the design has to become a real bent tube. These rules come from how signs are actually made.

Draw one continuous path
Letters and shapes must link up so the gas can flow evenly from one end of the tube to the other.
Plan where the gaps go
Sections of tube are painted black or another opaque colour to make the space between joined letters or forms.
Choose the colour by what is inside
Clear red is neon alone. Most blues, greens and yellows use argon and mercury with a coloured phosphor coating.
Think about the weather
Argon is not reliable in the cold, so a neon, argon and mercury mix is used outdoors to work more reliably in cold weather.

TWO NUMBERS WORTH KNOWING

What is in
the tube.

One figure on the classic gas mix,
one on how long a tube can last.

99.5%

Neon in a classic red tube

The classic neon lamp holds a mixture of neon (99.5%) and argon. Argon helps strike the arc; once warm, current flows through the neon and it glows.

GAS MIX · EDISON TECH CENTER

25,000 hours

Typical lamp life

Neon lamps are listed at about 25,000 hours, with about 50 lumens per watt for red and 65 for green. A well-made tube can last for decades.

LIFESPAN · EDISON TECH CENTER

The decades figure is from the GLOW exhibition historian's account of how neon signs are made; the hours and lumens figures are from the Edison Tech Center's history of electric lamps.

A QUICK COLOUR CHECK

Which colour
do you want?

Pick a colour to see what usually goes inside the tube to make it. The bar shows how much of the work a phosphor coating does, from none (gas alone in clear glass) to most.

Common gas and coating combinations; sign-makers can vary them.

Colour check

Choose a colourClear redPinkish whiteOrangeBlue or greenYellow

Clear redNeon, clear tube

The classic colour needs no coating: neon gas in a clear tube glows red-orange on its own.

Pinkish whiteHelium, clear tube

Helium in a clear tube gives a pinkish white. A whiter white can instead come from mercury vapour with a white phosphor.

OrangeNeon + yellow phosphor

Neon's own red-orange light combined with a yellow phosphor coating gives orange.

Blue or greenArgon, mercury, phosphor

Argon strikes the arc and warms up, mercury vapour gives off ultraviolet light, and the coloured phosphor turns that into visible blue or green.

YellowPhosphor does the work

Yellow usually comes from a yellow phosphor with argon and mercury, or with helium.

Source: Edison Tech Center, Neon and Argon Glow Lamps (colours section); Los Alamos National Laboratory periodic table entry for neon.

A single curved glass tube glowing red-orange against a dark brick wall — AI-generated image, not a photograph of a real person or place.

WHERE NEON CAME FROM

A blaze of
crimson light.

In 1898 the British chemists William Ramsay and Morris Travers found neon by evaporating liquid air. Collected in a spectrometer, the new gas glowed a brilliant red-orange; Travers wrote of a blaze of crimson light that was a sight never to forget. Ramsay won the 1904 Nobel Prize in Chemistry for discovering the inert gases in air.

Georges Claude collected neon in 1902 as a by-product of his air-liquefaction business and sealed it in a tube in 1910, showing the first neon lights in Paris that year. Homeowners disliked the intense colours, but from 1912 the tubes found success in advertising. When Claude's patent expired in the 1930s, hundreds of sign-makers joined the trade.

In conversation

Questions people ask

Are all neon signs filled with neon?

No. Real neon glows red-orange. Other colours use other gases, such as argon with mercury and a phosphor coating, helium, or coloured glass.

Why must a neon design be one continuous line?

The sign-maker bends a single length of tube to the traced pattern, and letter forms must be continuous for the gas to flow evenly from one end of the sign to the other.

How are the gaps between neon letters made?

Sections of the tube are painted black or another opaque colour, so the joining pieces stay dark when the sign is lit.

Who invented the neon sign?

William Ramsay and Morris Travers discovered neon in 1898. Georges Claude sealed neon in a tube in 1910 and showed the first neon lights in Paris; from 1912 they succeeded in advertising.

How long does a neon tube last?

The Edison Tech Center lists a lamp life of about 25,000 hours, and a historian of sign-making says a properly made tube can last for decades.

Sources

Each figure on this page comes from the sources below.

One line,
drawn in light.