Metal Halide bulbs glow a bright, intense white. Human eyes won’t have any problem seeing these. They’re considered one of the Best grow lights for entirely indoor hydroponic gardens because they do such a good job simulating the natural light spectrum and temperature. Depending on the size of your space, you probably don’t need very many of them. They glow so brightly you can use one for every 3–4 spotlight lamps you would’ve used.