clear & bright
炳 centers on light that is both clear and bright, like a flame that illuminates sharply without smoke or dimness.
炳 combines 火 (fire) with 丙, which likely contributes the sound and may suggest brightness or a flat surface that reflects light.
Fire 火 beside 丙, which looks like a flat, open frame, suggests a flame burning clearly and brightly without obstruction.
For ヘイ, imagine a bright hay bale catching fire: hay -> ヘイ, and the flames burn clear and bright.