The other day while I was sweeping for cobwebs 40 feet in the air ( stupid ass summer job) I got to thinking about if a blue cab would work for growing? If the inside walls are blue then that means it would absorb all light spectrums except blue which would in return be reflected. Do you think this would make any difference? Same would go for red walls or whatever color spectrum you wanted. Just my curious mind at work.
The part about the absorbtion would work, except the plant would absorb the light that comes directly from the bulb. If you were to bounce the light off a blue wall before hitting the plant, then you could force the plant to absorb only blue light. Or an easier way, get a blue lightbulb, then paint the walls blue. However, I'm not sure if any one color affects weed more than the other, but if there was some color that could alter the effects of growing, then yes your idea would work.