Supplemental light: PPFD vs Foot Candles

[rockyfarm]

After digging around in the lux/ppfd/dli information online, I've decided to modernize my growing conditions with a new PAR meter. I'm a little unclear on whether this meter will process all energy in the 400-700 band, or will weight it, favoring those wavelengths best for plants. At present, it sounds like we assume any energy within that band gets lumped into a single number.

I like the idea of the 'dli', since it explains how we can grow plants under lights with (relatively) low intensities by increasing daylength (and keeping the same exposure all day). This makes me wonder whether the low/moderate ppfd levels would produce darker green foliage than we normally would like to see, but the extra chlorophyll would actually be better adapted to process the low light more effectively than the light green foliage resulting from regular intense light. Any thoughts?