Source:UEFA Stadium Lighting Guide 2023, Maintenance factor. This article summarises the guide in our own words. LivePictureAI is not affiliated with or endorsed by UEFA; for any design or compliance decision, read the guide itself.
Floodlighting is one half of a wider picture-quality story we cover inshadows in live sports. At night, the stadium controls the light. By day, the sun does. The maintenance factor sits firmly in the first half, but it explains a lot about how stadium lighting is specified, and about what it can and cannot do for the broadcast.
What the UEFA Stadium Lighting Guide covers
The UEFA Stadium Lighting Guide 2023 is an online reference for designing and assessing floodlighting at football stadiums. It defines a set of UEFA illuminance levels (Elite Level A and Levels A to D) so that a stadium can be lit for the level of competition it hosts, and it covers horizontal and vertical illuminance and how to test them, uniformity, flicker, colour temperature, colour rendering, player shadows, power supply and the needs of broadcasters and media.
Television is one of the reasons those requirements exist. The guide’s section on broadcasters is brief: it states that broadcasters need certain illuminance conditions to produce high-quality pictures and points to the UEFA illuminance requirements for the figures. Thecolour renderingsection is more camera-minded, recommending that LED installations are assessed beyond the basic colour rendering index and noting the Television Lighting Consistency Index as a supplementary measure.
What the maintenance factor is (and why designers light above target)
Floodlights lose output as they age. Themaintenance factor section describes it as allowing for the loss of luminous flux caused by the “ageing and soiling of the light sources, reflectors and front glasses” (UEFA Stadium Lighting Guide 2023). The guide’s position is that the required average illuminance should be achieved during matches, not just on the day the system is commissioned.
The consequence is simple arithmetic. If a design uses a maintenance factor below 1, the new installation has to produce more light than the target so that, after the expected depreciation, it still meets it. The lower the factor, the bigger the margin a new system is designed with.
According to the guide:
- By default, designers should use the maintenance factor given in UEFA’s illuminance requirements.
- For LED luminaires, it does not recommend a maintenance factor above 0.90.
- In harsh environments with bad weather or airborne dirt, it suggests lower factors, typically 0.70 to 0.75 for HID lamps and 0.80 for LED.
- A factor may be adjusted where the information supports it: a proactive, frequent and documented maintenance programme (lamp replacement, cleaning, voltage regulation, testing), LED technology with low lumen depreciation, or constant-illumination lamp technology backed by manufacturer documentation.
Why it matters for broadcast: ageing lamps, dirt, and illuminance drifting over a season
For anyone running cameras at a stadium, the maintenance factor is a reminder that the light on the pitch is not a constant. The same ground can deliver a different amount of light in its first season and its fifth, and the difference depends on lamp technology, how dirty the front glasses get and how seriously the maintenance schedule is kept. The guide treats that drift as a design input precisely so the required level is still there on match night.
In practice, that drift lands on the vision engineers. Less light, or less even light, is absorbed by camera shading: opening the iris, adding gain, and matching cameras that see the pitch slightly differently. A well-run maintenance programme keeps that work predictable. That is a good reason for broadcasters to care about the maintenance factor, even though it is the stadium operator’s responsibility.
Floodlights at night versus sun and shadow by day
Everything above is about artificial light. In the sections we reviewed, the guide does not address daylight. Itsplayer shadowssection is about hard shadows produced by the floodlights themselves, for example from corner towers, and recommends lighting players from multiple directions to soften them.
The daytime problem is different in kind. When a stand blocks the sun from part of the pitch, the sunlit and shaded halves differ in brightness by far more than floodlights can even out. Switching the lights on lifts the shade a little, at a real energy cost, but it is a blunt instrument against direct sun. We go through the options in how to fix shadows in a football broadcast, and explain why a single exposure cannot serve both halves inmixed lighting and camera exposure.
Where a real-time AI layer fits
LivePictureAI is real-time AI that balances bright sunlight and deep shadows in live sports broadcasts. It works on the video signal as a processing layer, on the camera feeds or on the programme output, adding at most 100 ms of latency, and needs no new cameras or floodlights. Frame by frame, it rebalances sunlit and shaded regions within the same picture, so play in the shade becomes readable without blowing out the sunlit side.
To be clear about the boundaries: it works on the picture after the camera. It does not change the light on the pitch, and it does not replace compliance with UEFA lighting requirements or a sound maintenance programme. Where it can help is the daytime case the floodlights were never designed for, with the potential to reduce reliance on supplementary daytime lighting in some cases, depending on the footage.
LivePictureAI has been tested on football footage and we are validating it with selected partners after IBC 2026. If you would like to see it on your own stadium’s footage, get in touch.