Guod,I'm havin' some trouble seeing the attached pic... Wait a min... Relative power is not the power per nanometer relative to overall absolute power ? Am I mistaken ,here ? From graph ,there is no way ,to find out the absolute power... (And you can not relate-not that easy,at least.. - absolute Photometric values ,with a relative radiometric* graph.... Only radiometric values ... I.e . It may be that both CW & NW have the same radiometric output .. But human eye senses CW as the brightest from the two ,thus it has more lumens from NW .... Lumens does not apply (directly,at least) to this radiometric graph...) But the Rel.Power spectral graph , is a good way to see/comprehend , how the ( percentage of ) absolute radiant radiometric power,it is distributed relatively per nanometer.... 100 % rel. Power, means that the particular wl having a value of 100% R.P. , has the highest absolute value ,relatively to the rest wls .... So 85 % red means that this point(wl) of red has 85% of the power of the most powerful wl (being c.455 blue , at the example...).. So if overall absolute output power is 400 mW and at 455nm is 10mW (100 % RP ) ,then at red 600nm is 8.5 mW..... I do not think ,that I'm wrong there... Summed up from 400 to c.750 nm ,all the r.powers ,make up the total overall output power.. Meaning that ,all the surface that is inside(enclosed by ) the curve ,makes i.e 400 mW (if that is the total absolute power ,let's say..)...... *If the graph was for rel .photometric power , beyond 700 nm the curve ,would have been a flat line at zero ..... Same goes for light below 400 nm ....