If you are looking to purchase a new LCD monitor this is one attribute which you should consider, but is often hidden from the consumer. In fact, many don't realize that LCD's have different color depths.

A pixel is made up of three subpixels; one red, one green and one blue. Each subpixel can display one of a certain number of levels of color. This number determines the monitor's color depth. For example an LCD's may be listed as being able to display 16.7 million colors. The 16.7 million is a reference to 24-bit color.

Let's look at the math of 24 bit color. If you have used Photoshop, PSP or even used a color code in HTML, than you have encountered 24 bit color. Ever wonder why there are 256 levels of red, 256 levels of green and 256 levels of blue? Here is the answer.

Each subpixel can display 8-bit color. 8-bit can be represented mathematically as 2⁸ = 256. Therefore, each subpixel brings 256 colors and this gives us:

So, 24-bit color is created by 8-bit subpixels and this results in 16.7 million colors. This must mean that the LCD that lists 16.2 million colors has 8-bit subpixels? No, it doesn't.

In order to create fast response times in LCD monitors manufacturers may speed things up by taking colors away. They do this by lowering the color levels for each subpixel. The fewer the colors the faster they can render. The typical level of color is 6-bit for these screens. Doing the math we get the following:

Considerably fewer colors. So, how does the 16.2 million fit it? Manufacturers use dithering to trick the eye into thinking there are more colors than actually there are. This is the same technique used in print which is called halftoning. As was mentioned earlier, LCD color depth is usually not explicitly mentioned in the sales literature, but you can gleam it from the information provided. If a screen is listed as 16.7 million colors it most likely has 8-bit subpixels. A listing of 16 million or 16.2 million colors is likely to be the result of dithering 6-bit subpixels.

If you are a gamer, you may not care if a screen is 6-bit or 8-bit. You want a fast response time. However, if you are an artist or make your living from graphics, you know that color IS money. If you are looking for an LCD make sure your monitor has 8-bit subpixels.