Poor Man's CRI (colour rendering index)

Life pro tip: if you want to assess CRI (colour rendering index) on your own without any special equipment, use the blank side of a CD or DVD. Shine the light onto the CD at an oblique angle, and observe the rainbow reflection. The closer to a perfect rainbow the reflection is, the higher the CRI will be. If you see two, three our four discrete reflections in red, green, blue or violet, the CRI will be very low. "Average" lamps will be somewhere in between those extremes.