Home lighting is, in effect, an essential element of interior design. Having the right lighting system, suited and functional to the various needs of the space, allows you to enhance and enhance the aesthetics of the room.
There are many aspects and characteristics to consider when it comes to lighting: one of the most important concerns the properties of light sources, defined as color rendering index (CR), or simply CRI.
What is meant by Color Rendering Index
The color rendering index (CRI) of a light source indicates how natural the colors of the objects it illuminates appear.
In fact, the color of an object, when illuminated, does not emit its own light, but depends both on how it reflects light and on the light itself. It is therefore impossible and incorrect to speak of an object’s true color, in an absolute sense, without specifying the type of light source illuminating it.
If we were to define color rendering, we could say that it is a numerical value representing the ability of a light source to render and reflect the hue and colors of a given object.
How does color rendering work?
As mentioned, colors are the result of the visible light spectrum. The sun, the main source of natural light, emits white light containing wavelengths of different colors: red, orange, yellow, green, blue, and violet. When sunlight strikes an object, it partly absorbs the wavelengths and partly reflects them and bounces them back. The resulting color is the apparent color rendered to our eyes.
What is the CRI?
The Color Rendering Index (CRI) is based on a measurement scale from 0 to 100, where 0 represents the minimum and 100 the maximum rendering value of natural light on the object. The parameters on which color rendering is based were introduced in 1960 following an experiment by the International Authority on Light, Illumination and Color, which made the measurement range from 0 to 100 official.
How to use lights according to color rendering
The best type of light, which allows for the most natural color rendering of an object, is LED light, with an average CRI of around 80. This means that LED light can enhance the colors and naturalness of the illuminated object, providing brightness and chromatic depth.
Depending on the location of these lights, it is recommended to use different light sources that allow them to be functional for the location.
How to choose the correct color rendering index
There are five different color rendering classes to choose from, corresponding to different environments and spaces.
Group 1A is for spaces with a color rendering index (CR) greater than 90, such as hospitals, medical offices, clinics, and museums;
Category 1B, with a slightly lower color rendering index (CR) of 80-89, is for schools, offices, and homes;
Group 2 is for spaces such as gyms and corridors, where the light source can have an even lower CR, between 60 and 79 CR;
Class 3 is for workspaces such as warehouses, machine shops, and industrial interiors, where a light source with a color rendering index of up to 40 CR can be used;
Group 4 is for construction sites, parking lots, and platforms, which do not require very bright lighting and therefore require light sources with a very low CR, between 20 and 40 CR.
How to choose the right light bulb
When choosing a light source, it’s important to consider the balance between quality and energy consumption. Among the various types of lights available, halogen incandescent lamps are the best choice. These have better color rendering, with a perfect CRI score of 100. Perfect color rendering allows for more accurate and realistic color vision. However, they have the disadvantage of low energy efficiency and a shorter lifespan, estimated at around 2,000 hours.
Energy-saving lamps, on the other hand, offer a good alternative, despite a lower color rendering index (CRI), around 80 Ra. They have good energy efficiency, averaging around 6,000 hours.
The optimal solution, with the best quality-to-energy ratio, is LED lights. LED lights took longer to reach their peak performance due to their infrared end of the spectrum. But thanks to advances since the 1990s, these lights are now able to reflect colors more accurately. It reaches up to 90 RA, with a lifespan of over 40,000 hours, making it perfectly suited for home use.
As with any other application, it’s best to seek advice from industry experts, who can recommend the right bulbs through accurate and detailed lighting design.