What attracts heat more? black or aluminum foil?​

Black – the color that absorbs all visible wavelengths of light – attracts the most heat, followed by violet, indigo, blue, green, yellow, orange and red, in descending order.

Black Foil, BlackWrap, Lindcraft Foil, Cinefoil and Shadowfoils are all names for black aluminum foil that's primarily used to block out light and is attached to light fixtures and or their barn doors. Used in any situation where extreme heat might otherwise burn flags or cutters.