What is Color Rendering Index (CRI), Color Temperature (K) and Lumens?
CRI is a subjective measurement of how well a lamp source renders color. It’s a measurement of the degree of color shift an object undergoes when illuminated by a light source when compared to a reference source of comparable color temperature. Color temperature refers to the relative whiteness of a piece o tungsten steel heated to that temperature in degrees Kelvin. HPS has a warm (red) color temperature of around 2700k as compared to MH at 4200k, which has Lumen is a measurement of light output. It refers to the amount of light emitted by one candle that falls on one square foot of surface located at a distance of one foot from the candle. Traditionally, lumens have been the benchmark for a lights ability to grow plants; meaning better lights, better plants. However, recent studies have shown that broader color spectrum in the lamp will perform better then a light with high lumen output, especially when it comes to plant growth.
