The first report is from EURO third part laboratory, it analysed every wavelength from 380-780nm between a 400v 1000w high lumen HPS and 400v 1000w high PAR HPS. In file 2 I will tell you how to read above report. The picture is a comparison test between different brand from growershouse.com, hortilux only has 1960μmol/s under reflector, but Philips can get 2100μmol/s without reflector, you will clear which one is the best and which ones just cheated Last 2 are GE and Philips catalogue for your reference. I think most of friends here are end user, I am manufacture OEM for Philips and Sylvania, I don't have any customers in north american market, growerhouse's test report has told you why. Most of distributors purchased cheap high lumen HPS sell as real grow light,so I tell you the turth, hortilux is the only brand you can believe on north american market, but hortilux is not good enough as Philips, they may know but they don't want you know, I cannot find how much PAR value on their catalogue.
[SIZE=11pt]Also, Gavita has a great link to the explanation of PAR/PPF/PPFD:[/SIZE] [SIZE=11pt]http://www.gavita-holland.com/index.php/item/lumens-are-for-humans.html[/SIZE]