To each light its own colour
When you look at any object that doesn't emit light, you can see its colour because, after absorbing all visible light's wavelengths, it only reflects one or some of them. But have you ever noticed that colours change according to the light source that illuminates them? The best results are those of natural light, but there are some light bulbs which are very close to external light, as far as their CRI, Colour Rendering Index, is concerned.
What's the Colour Rendering Index?
The Colour Rendering Index is the measure of a light source's capacity for making the colours of the objects it illuminates look natural. The minimum CRI is 0, whereas the highest CRI is 100. The latter corresponds to natural external light, so the higher your light bulb's CRI is, the more natural the colours of your furniture will appear.
The values of the CRI are divided into five classes, and each of them suits a different space. The first two classes are:
- class 1A, with a CRI between 90 and 100: it corresponds to the highest quality of light and is therefore recommended in houses, museums and hospitals;
- class 1B, with a CRI from 80 to 89: the colour rendering of the lamp is good and ideal for offices, schools and shops.
But which are the CRI levels for the light bulbs on the market?
The relation between quality and energy efficiency of lamps
When you're about to choose a lamp, you should check the ratio between its quality of light and its energy efficiency. Halogen lamps have a good colour rendering level, namely 100, but their low energy efficiency and short lifespan, around 2.000 hours, are to their disadvantage.
On the other hand, energy-saving light bulbs have a slightly lower CRI, which is however a good one, that is 80, and last for around 6.000 hours.
Finally, the CRI of LEDs can be even higher than 90: they are therefore characterised by the same excellent colour-rendering ability as halogen lamps, but their energy efficiency is better. Besides lasting up to 40.000 hours, these light bulbs use 90% less energy than halogen lamps.
We've summed up the main features of different light bulbs in a chart: the choice is yours!