The Effects of Natural and Artificial Light on Interior Colour

The Effects of Natural and Artificial Light on Interior Colour

Colour is by no means a visually static element. It changes depending on the light source that one views it under. In addition to other variables,

the perceivable change that occurs in a colour’s appearance when viewed under different lighting conditions is technically termed Metamerism.


Three metrics, or standards of measurements, are used to understand how a lamp’s light will affect the colour of objects within any given space.

These metrics are:
a) Spectral Power Distribution – Shows the visible light spectrum and the light’s wavelength composition;
b) Colour Temperature – The color appearance of the lamp and the light it produces. Colour temperature is measured on the Kelvin scale (K);
c) Colour Rendering – A rating on the Colour Rendering Index (CRI) that ranges from 0-100. It describes how a light source makes an object’s colour appear before the human eye. It also takes into account the subtlety of variations in color shades. The greater the Colour Rendering Index, the better its colour rendering ability proves to be.
In the Southern hemisphere, North facing rooms receive direct sunlight and under it warm and saturated colours appear vivid, lively and bright. Cool colours on the other hand appear crisp, sharp and fresh.
Indirect light most common in south facing rooms is less intense, casts fewer shadows and is evenly distributed. This indirect light takes on a bluer undertone, giving cool hues an ever cooler quality, whilst intense colours typically take on a somewhat dull and sombre look and feel. By opting for soft neutrals, infused with warm undertones and incorporating light reflective décor accessories such as mirrors, glass and even glossy tiles, light can successfully be reflected back into the room, creating a more lively and light-filled environment.
When it comes to artificial light sources, the ‘colour temperature’ of light is what essentially affects the perceptible surface colour. Colour temperature can either enhance or distort the appearance of any given hue.
Various lights used in homes. It is interesting to note the following effects.

Firstly: Incandescent/tungsten lighting used in most home settings has a reddish/orange/yellow undertone that typically adds a warm, golden glow to warm hues, creams, off-whites and neutral beiges. This warmth is considered cosy and is often associated with the intimacy, comfort and charm of fires and candlelight. Incandescent light however dulls and murks cooler colours, giving blues, violets, greens and blue-greens a brownish undertone. If one however insists on painting blue under incandescent light sources, selecting a blue that is toned with red could counteract this metameric effect.

Secondly: Fluorescent light is blue tinged, reduces shadow effects, flattens texture and makes cool colours appear even cooler. When paired with warm hues, fluorescent lighting has the tendency to make these colours look somewhat muddy.

Thirdly: Halogen lighting or “white light” is the most accurate light source to view colour under as it has the closest approximation to natural daylight. It offers excellent colour rendition and is best used as accent lighting. Its whiter light output gives colours a sharper and crisper definition.

Lastly: LED (Light-Emitting Diode) and neon lights are predominantly used for colour-lighting effects within numerous interior settings.
It is of paramount importance to always brush out paint samples, and observe how well suited the chosen colours are, under the influence of both natural and artificial lighting sources within the architectonic environment.


Article first appeared inside the Shave STYLE GUIDE issue 8.