A painter has great depth of understanding of colour and qualities. A lighting designer is a painter and architecture is his canvas.
Our knowledge of colour comes from an early study in the first decade of the 20th century, the study classified colours according to their hue, value and chroma.
With this came the invention of the Munsell Colour System by American painter and teacher Albert Munsell, where he classified colours in accordance to hue the basic colour family, value a colour's lightness or darkness, and chroma a colours saturation or vividness.
A newer version of this system that we use nowadays depends on the Hue, Chroma, and Luminance of a colour. The HCL Colour Space Theory uses the "CIELAB" model defined by the International Commission on Illumination (CIE) in 1976. ￼
Colour space works 3 dimensionally, when selecting a colour our first focus should be hue, once we find the space in which our hue is located,next we select the chroma, the further away the colour is from the center, the more saturated it is. Lastly, we see the luminance of the colour, to determine how light or dark we want our colour to be.
Now that we have at least a basic understanding of how colour functions (if you haven't read our article on "Colour: Objects & Temperature" click here), We can start to discuss the combination of colour with light, not only is this important for lighting design, it's also very crucial for photographers, painters, cinematographers and anyone who's in learning the purest form of a colour.
For this we use the Colour Rendering Index, with it we measure how well an artificial light source renders colour in comparison to an ideal light source, such as sunlight. The index has an average value of 0 (in some cases the value may be less than 0!) to 100, With a CRI of 100, the most ideal example would be sunlight, values that are 90 and above are considered excellent, while scores below 80 are generally considered poor.
Below is a great example of how CRI works with LED lighting, where as in the image the higher the CRI of the LED lighting the closer we get to the real colour of an apple.
Book: Architectural Lighting by M. David Egan and Victor W. Olgyay (2nd Edition)