Thanks Zink.

dcarch

Thanks for the link. However most of the material there relates to quartz arc tube pulse-start vs. quartz arc tube probe-start metal halides. What is confusing, is that Ceramic Metal Halide is also pulse-start, but with ceramic arc tube. Virtually no information on CMH was there and the charts are not related to CMH. A 25watt self-ballasted CMH with PAR is available, that is the lowest to my knowledge.

The second link is an index of various topics. I went to the one on full-spectrum light. I found some bloopers:

"Any white light source will be effective at these levels (Lam and Levitt, 1999), so full-spectrum light source is in no way special for treatment of SAD."

However, "white light" is synonymous with "full-spectrum". The authors appear to be using a special definition that is contrary to standard usage and not conducive to easy communication.

"Full-spectrum light sources have no demonstrable benefit for dental health."

I think they meant to say "mental health" not "dental health". This sloppiness does detract from their credibility. If they don't spell-check, why should we assume they fact-check? There is a positive relationship between mental and over-all physical health. The authors are engineers, and dismiss SAD benefits as placebo (without bothering to use the term). They cherry-pick articles discounting health benefits of full spectrum light, ignoring the consensus of professional psychologists. People tend to specialize--electrical engineers tend to know nothing about plant growth or human psychology, while plant growers and psychologists tend to be less knowledgeable on electrical engineering.

The referenced article is concerned with human vision and not plant growth applications. For instance, the low pressure sodum (LPS) is rated at 180 lumens per watt but is labelled "efficacy" while the 100w warm CMH is rated at 93 lumens per watt. However "lumens" is a measure of efficiency for human vision, not plant growth. Even for humans, LPS is not very efficacious (efficient) because of the disconcerting effects of monochromatic light (inferior depth perception and mood, etc.).