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You know where to find the spectrum? I'm looking at page 11 of these specs but it doesn't even mention the color temperature.

OK. The result of this article is to estimate the radiometric efficiency of two white LEDs at 56% and at 76%. Clearly that is impossible so the question then arises of where does it go wrong. It goes wrong right here: Our model for the spectral distribution of a white LED is the radiance...

It's the green peak that gives it a higher lumen count but but that does not mean real power. Have you ever thought about a cool white with the super efficient Oslon 660nm as a red assist? Would it need additional 630nm to balance out the deep red?

Thanks for the link. The idea of cutting up the spectrum in three parts seems very logical to me - will adopt their cutoff wavelengths of 400, 520, 610 en 700 nm. Not sure about the V-C-F name though, red green and blue region is much easier to remember.

Good catch guod, did not realize the man was a nobel prize winner. Feel free to share any insight that the paper gives you.

Looks like the author of that paper tried to up his citation score, seeing how often he refers his own articles. You may think it sounds deep but it is actually pretty much bullshit. If you doubt the quantum nature of light, try looking through night vision goggles. You can then see the the...

The combined efficiency is just the product of the other two efficiencies. For the actual calculations I have put an extract of the relevant code below. The power going in is turned into heat plus radiant flux, nothing else, with no notion of 'unusable radiant flux'. Not sure that I follow...

Buddy this is a LED forum. From what I have read HPS has a radiometric efficiency of around 40% and a PAR efficiency of 89%.

OK, as promised it's now time for the Bridgelux Vero. The published spectrum looks very similar to the Cree: After digitizing the spectrum and having the Python script having a go at is, this is the absolute spectrum: The Decor spectrum is the purple curve. As you can see a grow room is just...

Sweet, the plant has that nice healthy green glow to it. There must be sufficient blue even in the 2700K. This was a bit of an open question for me, whether to use some extra 5000K or not. Spheda, I've seen the teardown pictures of the Philips lamp. For a grow light you surely don't want to...

Thanks for the compliment and the rep, glad you like it. Abiqua, the images should be fixed now. The algorithm is basically an inverse lumens calculation. It uses the CIE luminosity function and the relative power spectrum to first calculate the luminous efficacy of radiation (LER). The LER is...

Hi guys, While browsing the specs for the Cree CXA family (the new COBs) I happened by these promising looking spectra: Look at the beautiful purple curve of the high CRI part. It has extra power in the red and blue region, just where we want it. Surely it looks much better than the red...