Daylights are the ones that run during the day to simulate the sun. The white daylights usually run from 10-12 hours.
The blues/actinics...they are mostly to create a morning/evening effect, and to even out the yellow look that the daylights often give out.
These will come on a half hour to an hour before the daylights, STAY ON during the whole day along with the daylights, and then after the daylights shut off, these stay on another half hour to an hour.