CRI is a measure of how accurately a light source can reveal the intrinsic colors of what it is illuminating. Color is just the brain’s way of interpreting light wave frequency. When light hits an object, it absorbs some frequencies and reflects others. A red apple absorbs all the frequencies, except the red which bounces back to our eyes. BUT, for these frequencies to bounce BACK, they must be there in the first place. Some artificial light sources are better or worse at “rendering” true color because they have a wider and more complete spectrum, to begin with.
We all know that we look better in some light than others. That is true of our spaces as well. A beautiful space that is poorly lit or lit with inferior light sources can suddenly appear drab and depressing. It is important when designing and lighting your home to understand CRI and how lighting can affect your perception of space.