Multiphosphor vs. Triphosphor Lighting: What is the difference?

Multiphosphor and Triphosphor refer to two different types of fluorescent lighting. It refers to the blend of phosphors (this is the material coating the inside of the tube) which are then used to convert UV energy into visible non-harmful light. The type of phosphor blend results in variations between light quality, color rendering, energy efficiency, and cost.

How Do Fluorescent Lamps Work?

Before diving into the differences between these two types of fluorescent light, it's important to understand how a fluorescent lamp functions. In a fluorescent lamp the electric current excites mercury vapour within the lamp generating a short-wave UV light. The inner surface is then coated with a phosphor material to stop this UV light from being harmful to anyone who is perceiving it. The phosphor absorbs the UV energy and emits it as visible no-harmful light, and this process is called fluorescence.

Triphosphor Lamps

Triphosphor lamps have a blend of three narrow-band emitting rare-earth phosphors. These phosphors emit light in three types of narrow bands: red, green, and blue. By precisely balancing the intensity of these three bands, the lamp emits a crisp white light that is much more energy efficient than previous technologies.

a group of bottles — Photo by Chandu J S / Unsplash

Key Characteristics of Triphosphor Technology:

Characteristic	Description
Phosphor Composition	Three narrow-band rare-earth phosphors in the primary colours. (Red, Green, Blue).
Color Rendering Index (CRI)	High CRI usually 80–90+. Ideal for spaces where color accuracy is important.
Energy Efficiency	High. The narrow-band emission is very efficient at converting UV energy to visible light using a lower amount of wattage compared to its previous incandescent counterpart.
Long lasting bright light	Rare-earth phosphors deteriorate slowly leading to a longer lifespan and less depreciation of light over time.
Cost	Higher cost when first purchased but cheaper in the long run as it does not require as much energy for the same amount of light as incandescent technology.

A high CRI in these triphosphor lamps means the light and colour they provide appears brighter and more natural. This also means they can use less wattage for the amount of lumens (brightness of light) that they provide.

Multiphosphor Lamps

The term multiphosphor is often used broadly as a general rule refers to older fluorescent lamp technology such as Halophosphor lamps. These lamps use a wider mix of phosphors, sometimes containing calcium halophosphate. These lamps use this wider mix of phosphors to produce a broader band of light.

Key Characteristics of Multiphosphor Technology:

Characteristic	Description
Phosphor Composition	Made with a broader band halophosphate compound.
Color Rendering Index (CRI)	Lower typically being 60–70 which can lead to colors appearing dull or distorted.
Energy Efficiency	Lower than triphosphor. The broader spectral emission includes extra parts of the lighting spectrum that can lead to a lower luminous efficiency.
Light output maintenance	Halophosphate phosphors can deteriorate more quickly as they do more work to emit the light.
Cost	Lower at first due as they use lower cost materials but more more expensive in the long run as this will lead to faster deterioration.

Summary of the Main Differences

The biggest difference between triphosphor and multiphosphor lamps comes from the phosphors used within each light and the quality of the materials made leading to the quality of light produced. Triphosphor lamps will generally be of a higher quality as they use higher quality phosphors and while they may be more expensive initially than their Multiphoshor counterparts they will be cheaper in the long run as the built in components are often of a higher quality leading to a longer lasting light.

The term triphosphor is often used in favor of multiphosphor or to indicate them being of a higher quality. The lighting industry standard has overwhelmingly shifted towards triphosphor as well as LED technology as many countries move towards a demand for more energy efficient lighting.