How long does photoluminescent paint last?

Photoluminescence is often perceived as a simple technology: a material that captures energy from a light source and releases it in the dark. However, behind this principle, which is well known to the general public, lie real technical challenges, particularly when it comes to understanding how long a photoluminescent paint remains effective over time.

Many people wonder about the stability of the luminescence emitted, the resistance of the coating, or the impact of external conditions. The longevity of photoluminescent paints does not actually depend solely on their ability to glow, but on a set of parameters related to the materials, formulation, substrate, and environment in which they are used.

Our article aims to clarify these often misunderstood concepts and provide an accurate, factual overview of how phosphorescent products behave over time, in order to help decision-makers, local authorities, and professionals choose the solutions best suited to their needs.

Lifespan of photoluminescent paint: what you really need to look at

The longevity of the marking depends on the substrate, usage, and abrasion.

Contrary to popular belief, photoluminescence as a property does not have a limited lifespan: pigments retain their ability to recharge and emit light over the long term. What does change, however, is the condition of the paint film when subjected to environmental stresses.

To understand the longevity of a luminescent coating, it is therefore necessary to focus not on the light itself, but on the elements that influence the gradual wear and tear of the coating. Several parameters play a key role. Here are the main factors to consider:

The nature of the medium: an often underestimated factor

The behavior of paint depends largely on the material to which it is applied:

• New or good condition asphalt: even surface, good adhesion, minimal mechanical wear.
• Rough, old, or cracked asphalt: micro-roughness increases friction and accelerates paint film wear.
• Concrete substrates: often smoother, but susceptible to dusting or micro-delamination.

A support in good condition can significantly extend the longevity of the marking.

Use: traffic intensity and nature of traffic flows

The lifespan varies greatly depending on the type of use:

• Light traffic (pedestrians) → Very slow wear, extended service life.
• Regular bicycle traffic → Moderate wear: road markings remain intact for several years.
• Motor vehicle traffic → Higher stress, requiring more frequent replacement.

Studies conducted on different communities show that a trail with 2,000 to 3,000 daily users wears out much faster than a greenway with low traffic.

Mechanical abrasion: the primary cause of actual wear

Even high-performance paint will eventually be mechanically abraded. There are many factors that contribute to abrasion:

• Repeated friction from bicycle tires and scooters
• Deposits of sand, gravel, and dust
• Lateral movements caused by braking or changes in trajectory
• Passage of maintenance or service vehicles
• Mechanical snow removal (blades, brushes, etc.)

In France, it is estimated that a high-traffic area can generate up to several thousand tire passes per day on an urban bike path. The requirements for paint are therefore high.

Climatic conditions: UV rays, rain, thermal cycles

While UV rays do not alter photoluminescence, they can affect the performance of the binder that makes up the paint. Let's add to that:

• runoff effect
• freeze/thaw cycles
• temperature differences that can exceed 40°C between January and August
• continuous humidity in certain regions

Each element gradually contributes to the aging of the paint film.

Formulation quality: the determining factor

Not all photoluminescent paints are designed for intensive outdoor use. Some decorative or domestic paints, although bright, are not resistant to road traffic. Finally, one of the most decisive factors remains the quality of the formulation:

• choice of binder and resin
• photoluminescent pigment loading rate,
• particle size and type of fillers
• intrinsic resistance to UV and mechanical stress

This is what clearly differentiates decorative interior paint from photoluminescent road paint, which is designed to last on the ground and outdoors.

The lifespan of luminescent paint can vary considerably depending on the technology used and the conditions of use.

Observations on existing construction sites

Data compiled from more than 150 km of bike paths and greenways equipped with LuminoKrom® now allows us to establish robust trends. This field feedback, gathered from a wide variety of contexts (urban environments, forest areas, coastal environments, contrasting climates), shows that the technology performs consistently and predictably over time.

• In low-abrasion areas, such as rural greenways or pedestrian paths, the paint remains in excellent condition for between 4 and 6 years, with very limited loss of thickness and intact photoluminescence.
• In areas with moderate traffic, typical of urban or suburban cycle paths, the observed longevity is generally between 3 and 5 years, depending on the volume of bicycle traffic and the quality of the surface.
• In highly abrasive areas (roundabouts, intersections, lane entrances, braking zones), where friction is more intense and concentrated, renewal may be advisable after 2 to 3 years to ensure optimal visibility.

These figures are fully consistent with those observed for traditional professional road paints, confirming the robustness of LuminoKrom® luminescent technology despite its specific lighting requirements.

The analysis conducted on this section reveals an important lesson: the markings have held up well despite the lack of specific maintenance. Where one might expect significant deterioration or a significant loss of light performance, the track is, on the contrary, in very satisfactory overall condition. In the dark, the photoluminescence remains visible, legible, and impactful.

The slight decrease in light intensity observed after seven years, which is approximately 10%, is not due to physical fatigue of the photoluminescent pigments, which naturally retain their intrinsic emission capacity. This reduction is exclusively due to the gradual fouling of the paint film. Unlike traditional roads and highways, bike paths do not always benefit from regular maintenance to remove dust, pollen, plant matter, and microparticles that accumulate over the seasons. A thin but continuous layer of dirt can thus form, slightly reducing the amount of light that can be recharged during the day and therefore re-emitted at night.

This observation is crucial, as it shows that the decline in performance is not linked to the aging of the technology, but to a lack of maintenance of the surface. A simple mechanical or high-pressure cleaning operation could instantly restore much of the original brightness. The behavior observed on this track therefore shows that LuminoKrom®'s photoluminescence is not only stable over time, but can also be reactivated once the surface is cleaned.

Furthermore, the Pessac runway is an interesting case because it represents a rather unfavorable situation from a sustainability perspective:

• lack of maintenance for several years
• green environment bringing dust, pollen, and microparticles
• daily bicycle traffic
• natural exposure to rain, UV rays, temperature variations, and seasonal deposits

Despite this, the paint film is still present, and the photoluminescence continues to perform its role fully. These seven years of hindsight now allow us to draw solid conclusions about the actual longevity of photoluminescent markings outdoors. On a regularly maintained road or a road with less traffic, a LuminoKrom® product can last at least 6 to 7 years without any noticeable loss of performance. In some less abrasive or better maintained contexts, the duration can even reach 10 years, while maintaining effective photoluminescence and satisfactory nighttime readability.

In summary, the Pessac experiment provides real-world validation of the durability of LuminoKrom® technology. It demonstrates that, even without maintenance and in an environment subject to multiple stresses, the markings retain their remarkable quality over time. For local authorities, this field feedback provides concrete proof of LuminoKrom®'s ability to offer a reliable, durable, and economically viable solution for improving nighttime mobility safety.

Option 1 — Add a new layer of LuminoKrom® to the existing marking

This method is the simplest and most economical. It restores the luminescence of the marking by reinforcing the phosphorescent layer. The improvement is noticeable, but does not quite match the intensity achieved during the first application. This solution is suitable when the marking is still legible and in good mechanical condition.

Option 2 — Apply a white coat followed by a coat of LuminoKrom®

This option restores the performance of a new application, both in terms of daytime visibility and nighttime photoluminescence. It does not generate excessive thickness, as the original film has naturally lost some of its thickness over the years. This is the preferred solution when a complete upgrade is desired.

Many people confuse two very different concepts: the emission duration and the lifespan of a luminescent marking. Here are the characteristics to consider:

Outdoor photoluminescence works every night, as long as the paint film is intact.