Photoreactive panels are a form of active camouflage developed by the United Nations Space Command. The outer layer of the Semi-Powered Infiltration Armor is coated with photoreactive panels to hide the wearer from sight. While not as sophisticated as Covenant active camouflage, the technology advanced during the Human-Covenant War, with the newer SPI generation being fitted with more efficient photoreactive panels in 2551.
 List of appearances
- Halo: Ghosts of Onyx (First appearance)
- Halo: Evolutions - Essential Tales of the Halo Universe
- ^ Halo: Ghosts of Onyx, page 14
- ^ Halo: Ghosts of Onyx, page 99
- ^ Halo: Ghosts of Onyx, page 291
- ^ Halo: Evolutions - Essential Tales of the Halo Universe, "The Impossible Life and the Possible Death of Preston J. Cole", page 477