In the previous Lessons from the Stage series, I discussed the importance of Intensity as it relates to architectural lighting design. Lessons from the Stage Part II will discuss how the Color of light affects a design.
Lessons from the Stage Part II: the term “color” almost always refers to the hue of the filter or gel that is being used with a lighting fixture. Filters are available in nearly every shade of the rainbow and are used by the theatrical designers to evoke particular emotions in a scene, enhance the skin tones of actors, enliven the fabrics of costumes, or to change the appearance of the scenery to support the action of the scene.
In architectural design “color” can refer to a saturated hue that is achieved by using filters or color-changing LEDs, but more commonly is used to discuss the tint and color temperature of white light. White light is measured on a scale of Kelvin temperatures, with the scale being derived from the actual temperature of a black-body radiator that emits light. This very technical description is explained in detail here. In practical terms, color temperatures below 4000K indicate warm colored light while color temperatures at or above 4000K indicate cool colored light.
In addition to color temperature, the color rendering index, or CRI, of white light is a measure that indicates how well a source renders colors compared to a reference source of the same color temperature that renders colors with 100% accuracy. In general, the reference source is based on natural daylight, since daylight renders all colors perfectly. A CRI of 90 or above indicates a light source that is very accurate and acceptable, with CRIs below 70 being unacceptable for most applications. Another technical description here.
The designer’s choice of color temperature can greatly affect the way space appears. It is always a specification that must be thought about early on in the process. In most interior environments color temperatures in the 3000K-4000K range are suitable. A warmer light will create a more residential or hospitality appearance while cooler light will create a more professional or commercial appearance. Offices are usually best rendered at 3500K, not too warm or cool, and this temperature will nicely complement natural daylight throughout the year. A CRI of 85 or better is almost always used for interior spaces. This is of course not a hard and fast rule, different light sources are available in different color temperatures, so often compromises have to be made. LEDs, in particular, are available in a wide range of options. It is the designer’s job to pick color temperatures and CRIs of lamps that will accurately render colors in a space and create an aesthetic that complements the architecture.
While the majority of projects use only white light, it is becoming much more common to see saturated colors adorning buildings. Historically, colored light in architectural projects was achieved by placing colored glass filters over the apertures of lighting fixtures. Today, most colored light projects use color-changing LED fixtures. These fixtures operate by using an array of red, green, and blue LEDs. Intensity for each color is set by a programmable controller to mix the red, green, and blue LEDs and create more than 16 million colors (the same way a television or computer monitor works).
The use of color on an architectural project can create a very exciting space. Because of the LED revolution, the selection of color can be changed in the field. Many spaces have dynamic systems installed that constantly change the color of the light emitted. When using color a designer must decide on a palette to use, the style of effects that color-changing can create, and the speed of those effects. By changing these three variable endless aesthetic choices are possible. Color has a profound psychological effect and successful color projects evoke emotion in the people using a space. Warm colors are associated with emotions and characteristics like happiness, love, passion, excitement, and anger, while cool colors are associated with calm, sadness, wisdom, nature, and comfort. The unique thing about color is that every person and every culture experiences it differently, so a designer must create a space that uses a color that looks aesthetically correct to them and then leave it to the user to experience a reaction to it. For me, this is one of the most exciting aspects of color, every person who sees it will have a unique experience.
Warm hues create a dynamic space beneath an underpass. The wall feels bold and bright. In the middle of the winter, it would create a sense of warmth and security from the surroundings.
Blue light emitted by the wall washes over the plaza but enhances the evening activities of this space. Blue is an excellent complement to nighttime environments as it is usually associated with moonlight and allows white light to easily wash it out.
A rainbow combination of lights fills the streets with excitement and energy as colors can interact and move across buildings.
*Lighting Lesson by Stephen R. Hoppe, former Associate with The Lighting Practice