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  1. ArchDaily
  2. Projects
  3. Renovation
  4. France
  6. 2013
  7. Appartement Spectral / BETILLON / DORVAL‐BORY

Appartement Spectral / BETILLON / DORVAL‐BORY

  • 01:00 - 7 May, 2013
Appartement Spectral / BETILLON / DORVAL‐BORY


  • Architects

  • Location

    Levallois, Paris, France
  • Project Team

    Nicolas Dorval-Bory, Raphaël Bétillon (principals); Federica Sedda, José Rocha Gonçalves (interns)
  • Budget

    33,000 € VAT excluded
  • Area

    20.0 sqm
  • Project Year

  • Photographs

From the architect. Spectral apartment is a renovation project of a small Parisian studio, in which the lack of natural light led the client to ask us to intervene particularly on the issue of artificial light.


To do this, we chose to adopt a radical and binary approach by studying the spectral qualities of two different sources of artificial light.

Original Space
Original Space

Although often overlooked, since hardly noticeable in everyday use, the color rendering index, abbreviated CRI is one of the fundamental criteria for evaluating light. It depends more precisely on the spectral power distribution of light (SPD) and was identified in 1948 by the Scientific JP Bouma, then qualified by the International Commission on Illumination (CIE). The CRI of a light describes its ability to reflect accurate color of a surface. Bouma noticed that daylight was much better to estimate the colors and the work of the CIE established its value to 100 to determine the scale of CRI. Thus, a light with high CRI, close to 100, can render the colors properly (homogeneity in the spectral power distribution), while a low CRI is synonymous with loss of color range, so a disappearance of colors.


So in the manner of architect Philippe Rahm, the idea is to explore from an objective and scientific point of view the spectral qualities of these various light sources, and then to create an architecture that considers and even uses their special qualities.

Artificial Lighting Plan
Artificial Lighting Plan

The case of low-pressure sodium lamps (LPS) is in this particular. This system is extremely popular because of its particularly high efficiency (amount of light compared to consumed electricity) and it is used for the illumination of cities along the streets, roads and highways. Its characteristic color temperature gives this particular orangey shade to our nocturnal urban environment. However, these lamps have the lowest CRI, close to 0. This means that the light is monochromatic, in a wavelength of 589.3 nm, and cannot render any other color.


At night, along a road, we believe we can discern red from blue, but it is physically impossible with LPS light. A photo taken with such a light is monochromatic and necessarily, so to say, in black and white. Furthermore, for humans this wavelength is particularly suited to night vision, since the wavelengths around the blue (totally absent from LPS) induces a contraction of the pupil, limiting the amount of light perceived by the eye. After a few seconds of retina adaptation, the human brain rebalances the perceived color to produce a virtual spectrum, giving an impression of the scene as close as possible to objective reality. Now with LPS lighting, the brain has no other color to produce the virtual spectrum, so it literally produces a grayscale image.


So what does a space illuminated only in black and white become? What is the most appropriate architecture, the one that operates at best this particular artificial light. It is known that LPS lighting makes police work more difficult on the road at night, as distinguishing the color of a car is impossible. But one could imagine very intensely lit places where it would not be useful to perceive colors, and where this feature of artificial lighting would be known and controlled. Similarly, certain types of fluorescent lighting tubes with high CRI should be used for places that have been developed taking into account the abundance of some spectral peaks.


In our project, the first phase consisted of a division of program elements according on their spectral needs: which uses need a good color rendering, which spaces can be content with a very low color rendering? This first classification generates a hierarchy of space: on one side the kitchen, the living room, where distinguishing colors is required, on the other hand the bed and the shower where monochromatic light suffices.


This bipolarity between high and low CRI becomes the crucial element of space composition. Holding two separate light sources, a simple 2m high wall divides the studio and generates this composition. On one side an over 90 CRI lighting (940 fluorescent tubes) with a neutral color temperature (4000K), on the other side a warm light from low-pressure sodium lamps with zero CRI. Each of the two light sources produces about 16,000 lumens. The accurate analysis of the distribution of light in space then indicates the positioning of uses. Since there is no other source of artificial light in the studio those spaces are arranged in a form of free plan. As both sources can be switched independently, different lightning patterns appear, giving rise to unforeseen uses in particular areas of ​​the apartment.


The apartment is designed in a simple and neutral expression, without color or particular detail, annihilating any architectural expressiveness or narrative to leave only the logic of composition generated by light.

Location to be used only as a reference. It could indicate city/country but not exact address. Cite: "Appartement Spectral / BETILLON / DORVAL‐BORY" 07 May 2013. ArchDaily. Accessed . <>
Read comments


peterarch · December 26, 2014

Great refurb for the space. For one male person bachelor inhabitant it would be great. Couldnt possibly house a couple. No robes etc.

Visar · December 24, 2014

Where they cook? I see oven in design drawing but not in the pics. And where does the oven smell goes? Any ventilation there.

Erika Bosch · December 24, 2014 03:11 PM

do you mean the stove? is there and ventilation comes from the window right on front of it

Manh Tran · June 11, 2013

The idea of testing light spectrum is interesting. However, it would be a miracle if this couple won't kill themselves from falls or turn mentally disordered living in that all-white cage. How can we maintain spacial orientation when all surfaces, either vertical or horizontal or above or beneath, have the same color? Humans are like display items in this space, not its occupants. This is a typically model type of protograph-driven design.

AAlex · May 12, 2013

I would be crasy scared to go up and down from the bed. Ewww, a 90 degree turn... looks slippery. Also, are there any mirrors in the bathroom?

Hawra Esmaeil · May 08, 2013

i like the lighting aspect of the studio however, not so sure about the bed situation. they could have put a transparent barrier.. and even so, i would be so claustrophobic. also, i think that the kitchen is relatively bigger than the other areas of the apt.

glutamin · May 08, 2013

For the sake of humanity someone should tell them, architecture is not a poster design. This design aiming to kill people. Physically and psychologically.

oujaz · May 08, 2013

these guys thought so much of the lighting effect that they forgot to install a couch .

Moises Vera Soto · May 08, 2013

I think these guys like to make love in the kitchen and bathroom ... these look great!! ... and probably more comfortable than the bed :)

Khoa Vu · May 08, 2013

Simple, clean, and impressive!


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