You will find with a few exceptions the warm or soft white are 3000K the cool whites are 4100K and daylight are 6500K.Some manufacturers tweak these a bit but its pretty accurate
ballastman Reviewed by ballastman on . CFLs 27w 5500k or 42w 3500k? messed up on the title, should say "How important is spectrum for CFLs?" I am going to be growing 4 lowryders under fluorescents the whole way and I am wondering how important color temperature (spectrum) is. I can go to home depot and buy 4 42w cfls that have 2600 lumens each and 3500k color temp for $40 or I can go online and buy 4 42w cfls that have 2600 lumens and 5000k or 6500k color temp for $55-70. Is it worth the extra money to get full spectrum lighting since I am using the bulbs Rating: 5