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.
This mode uses six bitplanes (six bits per pixel).[3][5][6] The first five bitplanes index 32 colors selected from a 12-bit color space of 4096 possible colors. If the bit on the sixth bitplane is set, the display hardware halves the brightness of the corresponding color component.[7] This way 64 simultaneous colors are possible (32 arbitrary colors plus 32 half-bright components) while only using 32 color registers.[8] The number of color registers is a hardware limitation of pre-AGA chipsets used 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 the aforementioned restrictions.[9][15][16][17]
Some early versions of the first Amiga, the Amiga 1000, sold in the United States, lack the EHB video mode, which is present in all later Amiga models.[4][2]
^Mortimore, Eugene P. (1986). Amiga Programmer's Handbook. SYBEX. ISBN 978-0-89588-343-8.
^ abMaher, Jimmy (2018-01-26). The Future Was Here: The Commodore Amiga. MIT Press. ISBN 978-0-262-53569-4.
^ ab"Amiga Hardware Reference Manual: Color Selection in Extra Half Brite (EHB) Mode". Amiga Developer Docs. Retrieved 2022-11-19.
referred to as Extra-Half-Brite, Extra-Halfbrite, or EHB), is a planar display mode of the Amiga computer. This mode uses six bitplanes (six bits per pixel)...
from a palette of 4096 colors. Two special graphics modes are also available: Extra HalfBrite, which uses a sixth bitplane as a mask to cut the brightness...
Early versions of the Amiga 1000 sold in the United States did not have the Extra-HalfBritemode. In Hold-And-Modify (HAM) mode, each 6-bit pixel is interpreted...
specifically for the Commodore Amiga computer. It stores a LONG "viewport mode". This lets you specify Amiga display modes like "dual playfield" and "hold...
Deluxe Paint III appeared in 1989 and added support for Extra Halfbrite. New editing modes allowed one to stencil certain colors to protect them, so it...
available for either the Halfbritemode that added a copy of the first 32 colors but with half the intensity or Holds And Modify mode which allowed access...
could display 256 colors on the screen, while OCS based Amigas could only display 64 in HalfBritemode (32 colors and half-bright transformations). Although...