Quote:
Originally posted by JoséHempSeed
slow down with the calculators!
and on PAR: it also includes green. the only difference between par and lumens is that par is filtered (with very steep skirts) from 400 nm. to 700 nm. hope that helps  |
Yeah like I said there are better alternatives to PAR. Like LAI-PAR or YPF-PAR (i think that was it) it calculates based on plant efficency at the diffent spectrums. Like the plant uses blue light at a 80 percent efficency (it reflect 20 pecent blue light) where as plants use green lights to a 5% efficency. so you would multiply the efficiency of the plant times the par of the light at that kelvin..effectivly removing most of the green and yellow from the light lumen calc.
Lumens work cuase there is a direct relationship between lumens and pars but that doesnt mean that lumens arent wrong.
IE you can kinda tell how much money someone has by the car they drive.. nicer car.. more money.. but this is just a rule of thumb it can be wrong..it's much more beneficial to look in their wallet.
another test i would like to try.. would be to line your reflectors glass with Ggreenhouse PAR film... it is supposed to diffuse the light with respect to PAR. without hurting the total transmisssion of light... it is used in green houses all over the world. Supposedly at least in the legal plant world diffused light is way better than direct light. ( i'm going to test this when time and money provides)