color spectrum

im currently in the market for new lights and i keep seeing more and more companies make use of a particular datapoint (Color Temperature). Can anybody give me insight? There's a light i'd like to purchase however, it has the potion of choosing from 1750K-4000K and i know its K for Kelvin but i...

The Philips bulb comes in a 942 (4000k) and a 930)(3000k) Using them in veg and obviously the 942 is better with more blue but when I was running the 930 they looked alot more robust and generally bigger. I know the increase in blue in the 942 will keep them squat and promote side branching but...