And I'll take it one step farther. As applied technology, a single point PAR reading, even if "averaged" or somehow normalized within a single small area with multiple measurement data points, still tells you very little about the character of the PA photon field within that area. Your "laserbeam-5000" might still deliver an average PAR over a m2 of 800 - an excellent reading if construed to be representative of all points in the light field. But we of course know this is not true. A different light with a single point PAR reading of 700, but with a PAR variance of less than 10% (665-735) across a m2 field, would be a far superior light in virtually any horticultural application.
I'm wrapping up an extensive series of PAR and spectral testing of SolStrips and SolStrip-based lighting systems. In the process I began searching for benchmarks used by the industry, and trying to find comparable testing data from the big manufacturers. What I quickly discovered is that there really isn't any, even among the industry leaders.
Take Fluence. I consider the company and its founder Nick Klase one of those leaders. Crane's early embrace of distributed emitter architecture, and his move, bold at the time, to use mid-power full spectrum ("white") LED diodes as the foundation of Fluence's light engines, shows me that the company "gets it" when it comes to applied LED horticultural technology.
Here's what Klase said two years ago on a Fluence AMA on Reddit (before the company's $40 million buyout by Osram last year):
2 points·2 years ago
You shouldn't have a problem with the statement (it is after all, only the truth). You absolutely should have an issue with light manufacturers that don't publish their specifications. It's the latter which makes it difficult for people to know how much light to give their plants.
IMO, consumers should force manufacturers to provide PAR charts. There is no easy way around this, as the human eye (and cheap light meters which measure fc/lux) are useless unless everyone used the same spectrum (which they don't).
You either need a good PAR meter (which as you noted is expensive) or demand that manufacturers provide reliable PAR charts (which is free). Consumers have power. Stop spending money with companies who refuse to provide basic consumer data.
I realize the predicament, which is why we publish all specifications and PAR maps for our systems.
Except they don't, anymore. They publish a single-point PAR reading. Worse, they measure it at SIX INCHES from the lamp. Anyone with the most rudimentary understanding of the inverse square law of light can see how misleading such a measurement can be.
Fluence is a serious company. They are clearly making a play for the professional horticultural lighting market. Klase, a trained lighting engineer, now heads up their research dept. They have undoubtedly done all manner of testing on their lights, including extensive PAR mapping. So I thought maybe it was just a matter of asking. After all, Klase himself said light buyers should insist on manufacturers publishing PAR map data. So I asked:
Feb 11 at 1:05 PM
I've searched in vain on your website for PAR maps for your products. Nick Klase your CEO says at conferences that Fluence publishes all its PAR test data. I can only find the spec sheets, which do not include PAR distribution mapping (which I presume Fluence lamps excel at). Can you send me links or PDFs with your PAR maps?
Feb 12 at 2:07 PM
Thank you for writing in and inquiring about Fluence solutions. When Nick claims that we publish our test data, he is referring to the PPF, wattage, PPFD across a footprint, etc. We do not publish PAR maps of individual fixtures as many people then take it upon themselves to create a deployment strategy for their unique layout. Since we tie our success to the success of our customers, we want to ensure that the deployment strategy is to our standards as each project is different. I would love to get you in touch with the correct person to discuss the specifics of your project if you could tell me a little about your project.
So I replied with the Reddit quotes from Klase's 2017 AMA, where he explicitly states that light buyers should demand PAR maps. Fluence's sales rep replied as follows:
Feb 13 at 10:18 AM
In the time that the AMA was posted and now the decision to not publish individual fixture PAR maps was made.... As I stated in my previous, the removal of individual PAR maps is due to the fact that many people were taking those individual maps and trying to create a deployment strategy for their facility on their own. There is much nuance to the design and this is why we take the consultative approach to learn more about your unique needs, discuss the layout of your facility, and relay that information to our design team to provide a custom view. There has also been the recent release of our second generation of fixtures and there is discussion of standard layouts to give a view of our recommendations and what they provide in terms of PPFD.
When I replied that my "deployment strategy" was a 4x4 tent with reflective walls, the discussion ended. Not enough revenue potential to merit any further response from the Fluence sales team it seems.
Don't get me wrong - I think Fluence is best of breed among LED horti lamp manufacturers. Their lamp architecture should favor high and even distribution of PAR across the light field. I share the thesis behind that architecture with our SolStrip lamps. I want them to prove that distributed emitter architecture is the best way to design a horticultural lamp. But for some reason, they resist. They of course know what their PAR maps reveal, so I can only presume they do not show a performance advantage over their competitors.
My suspicion, having spent about 100 hours mapping our SolSheets and SolStix Racks in a 4x4 tent, is that the architecture and the diodes are really all that matters, cool space ship designs and clever marketing aside.
@Northern_Loki I would love to have you test a SolSheet X for me and the community, and add it to your published results. And I'd really love it if you PAR mapped a Spydrx in a reflective 4x4 space, so we could have a true comparison of the two. You have already done a great service to the OG community with this thread. How about comparing the flagship product of the industry's acknowledged LED technology leader with a homemade DIY lamp using the same technology that sells for less than half the price? Hint: at six inches, a center-point measurement of the SolSheet X exceeds the published PAR of the Fluence lamp, measured with an Apogee SQ-520.