OMB trust me you are more than capable of understanding PAR. I really wish growers would get PAR meters and use that as a standard rather than watts, lumens, etc. PAR (Photosynthetically Active Radiation) is a much more relevant and accurate way of measuring useable light. It ignores non-relevant wavelengths (such as green) so it gives a much more useful measure of your lighting intensity and your overall setup. PAR is a measurement of photosynthetic photon (light) flux. Having photon density in the right wavelengths will make a difference no matter what you are growing. Chlorophyll is actually found in several forms, and each of them absorb light energy at different wavelengths. There are a handful of other light absorbing pigments (eg carotenoids, xanthophylls) in plants that absorb light at specific wavelengths as well. Different pigments are more or less important at different stages of the plant's life, and in differing plant types. While it is certainly possible to "overload" a plant with sheer light intensity (scientists refer to this as "photo-bleaching"), in artificial grow operations the biggest problem with light is 1. not enough, 2. not the right kind, or 3. too much heat. The heated air near the light source is very hot, more than people would think. If you have glass in your light reflector, a layer of superheated air can form that will simply burn your plant. What a lot of people call "light-damage" is actually super-localized heat damage.