What Gases Are Used in Neon Signs?

Neon signs mainly use neon and argon gases, though mercury can be used to provide a broader range of colors.

Whether you’re going for a classic glow or a bold modern effect, this guide will help you choose the right gas for your needs. We’ll break down how each gas influences the color, brightness, and overall vibe of your neon sign.

Neon Gas Creates the Iconic Red-Orange Glow

Pure neon gas is used for the classic red-orange flow – the one you see in so many storefront windows. It remains the go-to choice for this effect, despite the growing number of options. 

Here’s how neon produces its warm glow:

1. Electric Current Excites Neon Atoms – When voltage is applied to the electrodes at each end of the tube, electrons flow through the gas, colliding with neon atoms.
2. Energy Absorption – These collisions transfer energy to the neon atoms, pushing their electrons into a higher energy state.
3. Light Emission – When the excited electrons return to their normal state, they release energy in the form of visible light, producing neon’s signature red-orange glow.

Fun fact: Neon was first used in illuminated signs in 1910 by French chemist Georges Claude, who demonstrated the technology at the Paris Motor Show.

Neon is efficient – you only need a small amount to produce a bright, eye-catching display. So, it is cost-effective for businesses looking to create eye-catching signs.

In addition, neon is ideal for cold climates because it doesn’t rely on mercury vapor to produce light, making it more reliable in low temperatures.

Mercury and Argon Work Together for Blue Light

Mercury vapor produces blue light when combined with argon and the appropriate phosphor coatings. Argon is a key piece of the puzzle because it has a low striking voltage – this helps initiate the electrical discharge.

Argon can be used as a primary gas in some lighted signs – but it rarely works alone.

What makes argon so useful is its versatility. When combined with mercury vapor and different phosphor coatings inside the glass tube, it can produce a wide range of colors – from bright green to soft pink.

On the other hand, argon-based signs can become sluggish in cold weather – typically below 45°F (7°C) – which may lead to dimming or flickering. This is why neon gas, which is less affected by low temperatures, is often preferred in colder climates.

Beyond the Basics: Specialty Gases for Unique Effects

Besides common gases, you can use specialty options to create distinctive effects for your signage needs:

Krypton

Krypton emits a whitish-yellow to bluish-white glow when electrified, and it is particularly useful in creating subtle effects. It’s even used in airport runway lighting due to its reliability and distinct appearance.

Xenon

Xenon creates a bluish or lavender glow, and is often chosen for high-end displays where unique color combinations are desired. Its distinctive glow makes it perfect for businesses wanting to create a premium appearance.

Helium

Helium emits a pinkish-red glow when ionized, but its light is much fainter than neon’s and is rarely used in commercial signs.

Mixing Gases and Techniques for Custom Effects

You can combine different gases and techniques to create specific colors and effects in your neon signs. Here are the factors that contribute to the end result:

• Glass color
• Phosphor coatings
• The pressure inside the tubes

By combining mercury vapor with different noble gases and phosphor coatings, sign makers can create virtually any color on the spectrum.

Find the Right Gas for Your Needs

For your neon sign, the right gas – or combination of gases – depends on the color, intensity, and mood you’re after. While some signs rely on a single gas, others use layered techniques to fine-tune the result. So, start by deciding how you want your sign to look, and then figure out – or ask your supplier – how to achieve your vision.