backlighting

/B AE1 K L AY0 T IH0 NG/
verb
  1. 1

    To illuminate something from behind.

noun
  1. 1

    The illumination of a photographic subject from the rear, causing edges to glow while other areas remain in shadow.

Source: https://en.wiktionary.org/wiki/backlight, https://en.wiktionary.org/wiki/backlighting