Colour Rendering Index definition/explanation

The Colour Rendering Index (CRI) measures how accurately a lamp reproduces the colours of the object it illuminates. The colours picked up by our eyes may differ from colours under natural lighting when using a low CRI lamp, and CRIs measure how accurate the lighting is to natural lighting so that we don’t see any changes in colour.

The value given by a CRI is an easily quantifiable score from 1-100, 100 being the best score and 1 being the worst.