I forgot to mention that she is a Red Maple (acer rubrum) of the Carolina Red variety.

Is your seedling a sangu kaku ?. I have one of these and it has right red stems and the leaves are the same too. i have Never tried using lights before whilst growing indoors, so maybe lose the lights for a while and keep an eye on it too see if it recovers. Try a god watering and fertilizer.

Sorry i did not notice your second post.

Your maple should be fine IMHO. It is reacting to the light intensity and producing pigments to shield against UV light that would normally accompany high intensity light, but this is not the case with your lighting set up (or should not be anyway). Unless the leaves are burning, then it should be fine with proper care. I currently have the same thing with "Caddo" Sugar Maple seedlings, and they are quit happy.

Arktrees

The only thing I will say is - when you do move it outside, put it first in bright shade - like on the north side of the house, or a heavily treed area, so it doesn't get any direct sun to speak of...then slowly acclimate it to sunlight...first an hour or two a day (after a week in the shade), then 4, etc. Otherwise you can burn the leaves - I've had trees completely defoliate by putting them straight in the sun after being indoors - and they didn't all recover.

Mostly you're acclimating to light conditions, but also temperature - your house probably doesn't vary much more than about 65-70 degrees, and outdoors can be whatever your area throws at it. I'd wait until the forecast shows a week of fairly mild weather (no colder than 50 at night and no hotter than the low 80s or so during the day) for a stretch of at least a few days before moving them out.

However, most maples, Acer rubrum included, do fine in shade as seedlings, so there would be no harm done keeping it in shade the first full season.

I have 3 Acer nigrum seedlings (that's all I could keep from my seeds that sprouted) that are doing nicely under lights and I plan to put them on the north side of a picket fence sometime in April (that is...if it EVER WARMS UP...) Mine are nice and stocky, since I started them under a fairly high-intensity CFL from the start, but the acclimation to outdoors is the same.