Amiga Halfbrite mode

Extra Half Brite (also referred to as Extra-Half-Brite, Extra-Halfbrite, or EHB),[1][2][3][4] is a planar display mode of the Amiga computer.

If the bit on the sixth bit plane is set, the display hardware halves the brightness of the corresponding color component.

[8] The number of color registers is a hardware limitation of pre-AGA chipsets in Amiga computers.

Some contemporary games (Fusion,[9] Defender of the Crown,[10] Agony,[11] Lotus II,[12] or Unreal[13]) and animations (HalfBrite Hill[4]) use EHB mode as a hardware-assisted means to display shadows or silhouettes.

[9][14] EHB is often used as general-purpose 64 color mode with its own restrictions.