What impacts nighttime luminescence?

Photoluminescence is an innovative solution for making night-time travel safer, thanks to road markings that glow in the dark without the need for an energy source.

Although photoluminescent markings are fully effective in the absence of light, they can lose their intensity when exposed to certain persistent light sources.

But why do these markings sometimes seem less visible than expected? What factors affect their night-time performance?

Whether it's street lighting, urban structures or even the full moon, these interferences compromise the optimal visibility of photoluminescent markings.

To guarantee maximum safety, it is crucial to understand these disruptive elements and adapt the layout of photoluminescent markings accordingly.

In this article, discover the main causes of nocturnal luminescence impairment and how to make the most of them.

Understanding photoluminescence and how it works

What is photoluminescence?

Photoluminescence is a physical phenomenon that enables certain materials to absorb natural or artificial light, then release it in the form of luminescence in the dark. This principle is at the heart of luminescent road marking products, which glow at night without the need for an external energy source.

What affects luminescence?

Several factors influence the intensity and duration of this light emission. These include the quality of the photoluminescent material, the amount of light absorbed, the exposure time and the ambient darkness.

The best-performing markers are capable of reproducing bright light for several hours after prolonged exposure. Our photoluminescent road paint, on the other hand, lasts for over 10 hours, completely autonomously.

However, for this brilliance to be perfectly perceptible, total darkness is essential. The presence of persistent light sources, such as street lighting or vehicle headlights, considerably reduces the visual contrast of our floor paints. This is why photoluminescent markings are so effective in areas with little or no artificial lighting.

Understanding these principles makes it easier to optimize the placement of luminescent markings to guarantee maximum safety at night.

Artificial light pollution

Photoluminescent marking works best in the total absence of light. Yet in many urban and suburban areas, artificial light sources are omnipresent. Streetlights too close to photoluminescent markings considerably reduce their visibility, as artificial light alters the contrast between luminescence and darkness.

Sports stadiums, public or private buildings and illuminated signs also generate residual light that impairs marker performance. This light pollution creates a veil of light that prevents markings from standing out clearly in the dark. Even though photoluminescence is still active, the human eye perceives the intensity of the markings less clearly when the environment is already illuminated.

Natural light: the full moon, an underestimated factor

It's often thought that only artificial light disturbs photoluminescence, but a full moon is also a factor. On a full moon night, natural light intensity is sufficient to illuminate the ground, reducing the visual impact of luminescent markings. Conversely, a moonless night creates total darkness, ideal for markings to shine optimally. The visual contrast between the luminescent markings and the environment is then at its maximum, offering the user a better perception.

It is therefore crucial to take these persistent light sources into account when designing and installing photoluminescent markings. It's important to bear in mind that at certain times of the year, such as when there's a full moon, a photoluminescent ground marking on a cycle path, for example, will be less visible than at other times of the year. This phenomenon is scientific, and does not call into question the quality or durability of our paints.

While the presence of light - natural or artificial - can reduce the perceived intensity of photoluminescent markings, it does not call into question their usefulness. On the contrary, photoluminescence reveals its full value in environments plunged into deep darkness, where no other visual cues are available.

This is the case for isolated areas: unlit country roads, cycle paths on the outskirts of towns, footpaths in forests, riverbanks, or even protected natural areas. These places, often far from lighting networks, present greater risks for night-time users. Photoluminescent paint acts as a visual safety relay, making it possible to follow a path, find one's bearings or anticipate an obstacle, even when ambient light is almost non-existent.

Another key example is the unpredictable but frequent failure of public or artificial lighting. In these situations, photoluminescent markings take over to ensure continuity of visibility, without the need for electricity. They can be used to direct users to evacuation zones or emergency exits on walls or floors.

Photoluminescent paint therefore makes perfect sense in very low-light situations, where it becomes a silent but indispensable guide to the safety of pedestrians, cyclists and other vehicles.