The illuminated ceiling or stretch ceiling is very interesting trend in interior lighting. By using a translucent material many square meters in size with a backlighting system, a diffuse, even and relaxing illumination of interiors can be created. The main advantage of this type of lighting is the absence of glare, as the light sources are distributed over a large area and hidden behind the material.
The backlight source is usually low or medium brightness LEDs (5 to 50 lumens) mounted on strips or modules. Since the illuminated surface has a large area, such low power illumination is the best choice.
Illuminated stretch ceilings can have personalized shapes and even feature translucent images. They can therefore influence the overall design of a room much more than other lighting fixtures. From a lighting design perspective, uniform light should be supplemented by spotlights or lamps that can draw attention to specific areas or objects.
The proper design and installation of a luminous ceiling has a number of unique challenges that we will address in this article.
1. The translucent stretch ceiling must have good light transmission
Since a stretch ceiling uses a translucent material to cover the LED light sources, it is important to consider the light transmission. For simple white ceilings, we recommend a light transmission rate of at least 50%. If you have to choose between different manufacturers, you should consider installing the material with the highest transmission rate, as this value has an important influence on the installation and operating costs of the luminous ceiling.
When choosing a light source, you should consider the light transmission rate. For example, if you need 5000 lumens for a 20 sqm living room, the luminous flux of the LEDs behind a translucent material with 50% rate should be 10000 lm.
If you are using a printed image on the ceiling, you should avoid colours that are very absorbent, such as black or dark grey while warm colours have the best results.
2. Choose the optimum distance between the LEDs and the stretch ceiling
The stretch ceiling should have a uniform illumination, without hotspots or dark areas, whereby this uniformity is the attraction of this lighting method. To achieve this, the LEDs must be evenly distributed behind the translucent material.
For most LEDs with an illumination angle of 120 degrees, the distance between the individual LED strips or modules should be equal to the distance between the LEDs and the stretch ceiling. Some special LEDs have an angle of 180 degrees and for them the distance ratio should be 1.5.
For best results, we recommend a distance between the light sources and the translucent material of at least 30 cm and at most, about 50 cm. While a smaller value is possible, this would mean that many more LEDs would have to be used to achieve uniformity, which would have a significant impact on installation and operating costs.
- 120 deg view angle: 30 cm
- 180 deg view angle: 45 cm
3. Use of energy-efficient light sources
Choose LED modules or strips with high energy efficiency, at least 100 lm/w, so the stretch ceiling has the highest luminous flux with the lowest energy consumption.
4. Choose an LED light source with the correct light output and number of LEDs.
Lighting via a stretch ceiling can be used in a variety of ways such as guiding people, highlight certain areas or express a particular design trend while providing ambient, general or even task lighting.
We strongly recommend that you consider the purpose of lighting when you choose the type of light source to be used. The following values of luminous flux per square metre for the LED modules, can serve as a useful guide for a white stretch ceiling with 50% light transmission rate:
A) Ambient light: 500-1000 lumens per square meter
B) General lighting for residential: 1000-2000 lumens per square meter
C) General lighting for commercial and business applications or workplace lighting: 2000 - 8000lumens per square meter
5. The LED strips or modules used for back-light must be easy to install
Since stretch ceilings require many LEDs, they must be easy to install and use as few auxiliary parts as possible, such as wires, plugs, screws or transformers. For large areas, we recommend square or rectangular LED modules that are at least 25 cm wide, as they are easier to place evenly compared to LED strips.
6. Use LED modules or strips with the best light quality, spectrum and color rendering index.
If the purpose of the stretch ceiling is general lighting we recommend light sources with a high quality spectrum and CRI of minium 90.
Currently the best quality of light for LEDs come is provided by the full spectrum technology, such as Nichia Optisolis and Seoul Semiconductor SunLike, both with almost day-like spectrum and maximum scores for all the CRI test colors. Their spectrum and how it compares to sunlight and other light sources can be seen below.
We recommend LED modules or strips with minimum CRI80 for all work and living places, such as office, living room, dining room bedroom and so on with CRI95+ as the recommended value.
7. Install LED modules or strips with the longest lifetime, the lowest color shift and best lumen maintenance.
Long lasting LED light sources with minimal color shift in time are recommended, especially for installations with considerable size. If the brightness of the light source fades too soon or the color temperature changes the total replacement of the installation could be the only solution for uniform lighting.
For example, if "LEDs 1" are used in the installation and the light changes as in the image on the right, replacing only some sections with "LEDs 2" will exacerbate the lack of uniformity, as in the image below.
At Lumistrips you will find the BackMatrix LED modules which can deliver the best lighting for stretched ceilings. They are very easy to install, have a high luminous flux and even are available with LEDs that have 180 degree view angle.
1. BackMatrix Performer LED modules with 2700K, 4000K or tunable white 2700-6500K. We recommend 4 pcs per square meter for uniform lighting at minim 30 cm depth
2. BackMatrix Professional LED modules with 3000K, 4000K or RGB+W. 4 pcs per square meter recommended for uniform lighting at minim 30 cm depth