Everything in computer memory is stored in the form of bits. The 8-bit color graphics is a widely used technique to store the information about an image to an image file or in a computer’s memory. In graphics scheme, an 8-bit byte is used to represent each pixel. Thus, the maximum number of colors which can be displayed using this scheme is 2^8, i.e. 256.
There are two common ways of representing 8-bit color graphics-
The first one employs a distinct palette of 256 colors; each of the color in this palette has an associated red, green, and blue (RGB) value.
· The original 320×200 mode in a VGA card has a palette of 256 on-screen colors which are chosen from among 262,144 colors, where each colored pixel is displayed using 18 bits- 6 bits for each, red, green, and blue.
· Older cards, which came even before the VGA, like the Professional Graphics Controller have a palette of just 4,096 colors, each pixel being displayed by 12 bits- 4 for each of red, green, and blue, from which 256 are picked for its palette.
· In most of the color maps which are used today, every color is picked from a palette of 16,777,216 colors, which means it is displayed using 24 bits, 8 for each red, green and blue.
In the second method, the 8 bits directly represent red, green, and blue values; generally 3 bits are used for red, 3 bits for green & 2 bits for blue. This form is known as 8-bit true color. It is similar to the 15-bit, 16-bit, and 24-bit true color modes, in not making use of a palette at all.
The representation of given color scheme is as follows-
Raw image data is also stored in addition to a local image palette of 256 colors in most of the 8 color formats. When such an image needs to be shown using 8-bit graphics hardware, the global palette of graphics hardware is overwritten by the local image palette. Due to this, the other images on the screen can have wild distortions in their color due to the disparity in their palettes. To tackle this issue, when concurrent images from different sources are displayed, then programs such as web browsers on 8-bit graphics hardware use some kind of dithering to remap all the images on the screen to the same palette, to prevent any distortions.
At present, most graphics hardware display in either 24-bit true color or 32-bit true color, this has made image distortion a problem of the past. However, to save bandwidth, most remote desktop software like the Remote Desktop Protocol and the Virtual Network Computer are designed to switch to 8-bit color.
Unfortunately, some of the things today do not look good in 8 bit, as you can see from this real estate agent’s logo…