Color Rendering Index, commonly referred to as CRI, is a method we can use to measure how color looks to the human eyes, depending on the light source as compared to the sun. The CRI provides a scale of values up to 100, with 100 being the best color rendering light quality and a value below zero representing very poor color rendering. When a light has a CRI of 100, it means that there is no difference in color rendition between the light and the reference light (the sun). Likewise, a CRI of 75 means that the light bulb renders a 75% replication of the visible colors that the sun shows, given that both lights have the same color temperature. That is the cri of the average streetlight.  Our eyes are sensitive to light quality and color. The higher the CRI value, the more accurate the colors will be.