Difference between revisions of "BitDepth"

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Bit depth is used to control how many colors an image holds. The more colors, the smoother the image.
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= Bit Depth =
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There are two common measurements: Bits Per Pixel ([[BPP]]) and Bits Per Channel ([[BPC]]). Usually bit depth means BPP.
  
Bitdepth is used to denote how many colors a game or application needs to function properly, which is the number of colors plus other channels like [[AlphaChannel|alpha]]. The more colors, the smoother the image. 1-bit is two colors-- black and white. 2-bit is four colors, 4-bit is sixteen, 8-bit is 256 colors, etc.  
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1-bit is two colors (black and white), 2-bit is four colors, 4-bit is sixteen, 8-bit is 256 colors, 16-bit is 65536 colors, etc.  
The number of colors at any bit depth = 2bitdepth. For instance, 8-bit = 28 = 2x2x2x2x2x2x2x2 = 256 colors.
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If game uses alpha or [[HeightMap|heightmaps]], then they are additional channels that can be added to the bitdepth number. 16-bit is 65536 colors without any additional channels, but if you want to add an alpha channel, then 16 would be divided into [[RGB]] and alpha, which can be done a number of ways. For example, if you use 4 bits each for Red, Green, and Blue, then that leaves 4 bits for the alpha, so you have 16 colors for alpha. Or else 5 bits for each RGB means you have 1-bit for alpha, which is only 2 colors, but gives you more RGB colors to work with. It's a trade-off.
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The number of colors at any bit depth is 2 to the power of the bitdepth. For instance, 8-bit = 2 to the 8th power = 2x2x2x2x2x2x2x2 = 256 colors.
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If game uses alpha or [[HeightMap|heightmaps]], then they are additional channels that can be added to the bitdepth number.  
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16-bit is 65536 colors without any additional channels, but if you want to add an alpha channel, then 16 would be divided into [[RGB]] and alpha, which can be done a number of ways. For example, if you use 4 bits each for Red, Green, and Blue, then that is (4 + 4 + 4) which leaves 4 bits for the alpha, which is 16 grays. Or you can use 5 bits for each RGB which means you get 1-bit for alpha, which is only 2 grays, but this gives you more RGB colors to work with. It's a trade-off.
 
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[[Category:Glossary]]
 
[[Category:Glossary]]

Latest revision as of 07:02, 9 April 2015

Bit depth is used to control how many colors an image holds. The more colors, the smoother the image.

There are two common measurements: Bits Per Pixel (BPP) and Bits Per Channel (BPC). Usually bit depth means BPP.

1-bit is two colors (black and white), 2-bit is four colors, 4-bit is sixteen, 8-bit is 256 colors, 16-bit is 65536 colors, etc.

The number of colors at any bit depth is 2 to the power of the bitdepth. For instance, 8-bit = 2 to the 8th power = 2x2x2x2x2x2x2x2 = 256 colors.

If game uses alpha or heightmaps, then they are additional channels that can be added to the bitdepth number.

16-bit is 65536 colors without any additional channels, but if you want to add an alpha channel, then 16 would be divided into RGB and alpha, which can be done a number of ways. For example, if you use 4 bits each for Red, Green, and Blue, then that is (4 + 4 + 4) which leaves 4 bits for the alpha, which is 16 grays. Or you can use 5 bits for each RGB which means you get 1-bit for alpha, which is only 2 grays, but this gives you more RGB colors to work with. It's a trade-off.


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