LCD Monitors and Color Gamuts

Color gamut refers to the levels of colors that can potentially be displayed by a device. There are two types of color gamuts, additive and subtractive. Additive refers to the color that's generated by mixing colored light to generate a final color. Subtractive color mixes dyes that prevent reflection of light that then produces a color.

Additive vs. Subtractive

Additive color gamut is the style used by computers, televisions, and other devices. It's more often referred to as RGB based on the red, green, and blue light used to generate the colors.

The subtractive color gamut approach governs all printed media such as photos, magazines, and books. It's also generally referred to as CMYK based on the cyan, magenta, yellow, and black pigments used in the printing.

sRGB, AdobeRGB, NTSC, and CIE 1976

To quantify how many colors a device can handle, it uses one of the standardized color gamuts that define a particular range of colors. The most common of the RGB-based color gamuts is sRGB. This is the typical color gamut used for computer displays, TVs, cameras, video recorders, and related consumer electronics. It's one of the oldest and narrowest of the color gamuts used for computer and consumer electronics.

AdobeRGB was developed by Adobe as a color gamut to provide a wider range of colors than sRGB. The purpose was to give professionals a greater level of color when they work on graphics and photos before converting for print. The wider AdobeRGB gamut gives a better translation of colors to print than sRGB.

NTSC is the color space developed for the range of colors that can be represented to the human eye. It's also the only representative of the perceived colors that humans can see and isn't the widest color gamut possible. Many may think this has to do with the television standard that it's named after, but it's not. Most real-world devices to date can't reach this level of color in a display.

The last of the color gamuts that may be referenced in LCD monitor color ability is the CIE 1976. The CIE color spaces were one of the first ways to define mathematically specific colors. The 1976 version of this is a specific color space that charts the performance of other color spaces. It's generally fairly narrow and, as a result, is one that many companies use, as it tends to have a higher percentage number than the others.

What Is the Typical Color Gamut of a Display?

Monitors are generally rated by the percentage of colors out of a color gamut that's possible. Thus, a monitor rated at 100 percent of NTSC can display all the colors within the NTSC color gamut. A screen with 50 percent of the NTSC color gamut can only represent half of those colors.

The average computer monitor displays around 70 to 75 percent of the NTSC color gamut. This capability is sufficient for most people, as 72 percent of NTSC is roughly equivalent to 100 percent of the sRGB color gamut.

An LCD monitor's backlight is the key factor in determining its overall color gamut. The most common backlight used in an LCD is a Cold-Cathode Fluorescent Light. These can generally produce around 75 percent of the NTSC color gamut. Improved CCFL lights generate roughly 100 percent of NTSC. Newer LED backlighting can generate greater than 100 percent. Still, most LCDs use a less expensive LED system that produces a lower level of potential color gamut that's closer to generic CCFL.

What to Look for When Buying a Monitor

If an LCD monitor's color is an important feature for you, find out how many colors it can represent. Manufacturer specs that list the number of colors are generally not useful and typically inaccurate when it comes to what a monitor actually displays versus what it theoretically can display.

Here's a quick list of the common ranges for different levels of displays:

• Average LCD: 70 to 75 percent of NTSC.
• Professional non-Wide Gamut LCD: 80 to 90 percent of NTSC.
• Wide Gamut CCFL LCD: 92 to 100 percent of NTSC.
• Wide Gamut LED LCD: Over 100 percent of NTSC.