LCD Monitors and Color Gamuts

Determining how well an LCD monitor is at reproducing color

Color gamut refers to the various levels of colors that can potentially be displayed by a device. There are actually two types of color gamuts, additive and subtractive. Additive refers to the color that is generated by mixing together colored light to generate a final color. This is the style used by computers, televisions and other devices.

Flat Screen TV on Designer Wall (XXXL)
4FR / Getty Images

It is more often referred to as RGB based on the red, green and blue light used to generate the colors. Subtractive color mixes dyes that prevent reflection of light that then produces a color. This approach governs all printed media such as photos, magazines and books. It is 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 much color a device can handle, it uses one of the standardized color gamuts that define a particular range of color. The most common of the RGB based color gamuts is sRGB. This is the typical color gamut used for all computer displays, TVs, cameras, video recorders and related consumer electronics. It is one of the oldest and therefore narrowest of the color gamuts that is used for computer and consumer electronics.

AdobeRGB was developed by Adobe as a color gamut to provide a wider range of colors than sRGB as a means 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 was the color space developed for the range of colors that can be represented to the human eye. It is also the only representative of the perceived colors that humans can see and is not actually the widest color gamut possible. Many may think that this has to do with the television standard that it is named after, but it is not. Most real-world devices to date do not have the ability to actually 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 is used for charting the performance of other color spaces. It is generally fairly narrow and as a result is one that many companies like to use as it tends to have a higher percentage number than the others.

So, to quantify the various color gamuts in terms of their relative range of color of narrowest to widest would be CIE 1976 < sRGB < AdobeRGB < NTSC. In general, displays are generally referred to compared to the NTSC color standard unless they state a different standard.

What is the Typical Color Gamut of a Display?

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

The average computer monitor will display around 70 percent to 75 percent of the NTSC color gamut. This capability is fine for most people—72 percent of NTSC is roughly equivalent to 100 percent of the sRGB color gamut) The CRTs used in most old tube televisions and color monitors also produced roughly a 70 percent color gamut.

For a display to be listed as a wide gamut, it generally needs to produce at least a 92 percent NTSC 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 the 75 percent NTSC color gamut. Improved CCFL lights generate roughly 100 percent NTSC. Newer LED backlighting has been able to actually generate greater than 100 percent NTSC color gamuts. Having said that, most LCDs use a less expensive LED system that produces a lower level of potential color gamut that is closer to generic CCFL.

Summary

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

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

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

Most displays when they are shipped go through very basic color calibration and will be slightly off in one or more areas. As a result, calibrate your display with proper profiles and adjustments using a calibration tool.