lighting information is best taken from doc bruce bugbee from utah state... hes got some good papers on LED vs HID... hes also quite possible the leading plant scientis in the country and the guy who NASA turn to when they need to figure out how to grow plants in space.. there is some videos on youtube and you can find some other informatiuon from jsut searching google.
this is from mammoth lights website but they are basically paroting bugbees research...
Bottom threshold for optimal growth and photosynthesis is a DLI of 22:
24/0 schedule: 254.6 micromoles/m2/s-1
18/6 schedule: 339.5 micromoles/m2/s-1
12/12 schedule: 509.25 micromoles/m2/s-1
The Top threshold for optimal growth and photosynthesis is a DLI of 65 moles per day.
***Extremely important notice, only go up to these amounts if you are using supplemental CO2, do not go this high if you are not using supplemental CO2 as you will actually slow down photosynthesis and waste energy.
24/0 schedule: 752.31 micromoles/m2/s-1
18/6 schedule: 1003.08 micromoles/m2/s-1
12/12 schedule: 1504.6 micromoles/m2/s-1
The generally accepted guidelines for artificial light PPFD in flowering during 12/12:
PPFD of at least 510 micromoles/m2/s-1 for the low end of optimal intensity
PPFD of at least 800-1100 micromoles/m2/s-1 for optimal lighting WITHOUT additional CO2.
PPFD of at least 800-1500 micromoles/m2/s-1 for optimal lighting WITH additional CO2.
hope that helps