umbrella hood white or silver?

I got an old school 1000 watt mh probe start setup with an umbrella hood the hood pieces have a white side and a bare metal side which side am I suppost to point down?

The metal side(reflective) points down.

im thinkin white is better than bright metal or foil for reflective value,but there is a sticky on site u can read to be sure. i use panda film and flat white walls

Thanks FF!