| A color management system that lets a computer handle a large number of colors without devoting an excessive amount of memory to keeping track of each possible shade.
Modern PCs are generally capable of dealing with up to 24-bit color. In brief, that means they can handle 224 colors (or 16,777,216 different shades)—about the maximum that most people are able to perceive. Furthermore, today's high-resolution monitors will display up to 1,280 pixels across x 1,024 pixels down. That's a total of 1,310,720 individual color points on a screen, each one of which could be any of almost 16.8 million colors. To keep track of all of that requires a great deal of memory.
CLUTs minimize the memory requirement by working on the assumption that while more than 16 million colors may be possible, only a very limited number of those colors are likely to be in use at one time. Tables may be of any size, but an 8-bit table is among the most common. It is an array of 28, or 256 cells, each of which can contain the information about any of the possible colors. Whatever colors are specified in the table at any given time are the colors available for display. So for any specific display, any 256 of the 16.8 million possible colors are "on call" for use. This is often referred to as the color palette.
A color look-up table may reside in hardware, such as in the memory chip of a video card, or in software, such as when the information is stored as part of a graphic image's file. |
