Color accuracy defines how well a monitor can reproduce colors and shades as intended, and it affects whatever we're viewing. Although most people won't notice slightly inaccurate colors, it could get distracting when the colors are very inaccurate and you're seeing orange when you're supposed to be seeing red. You could have the best-performing, 4k monitor with the latest features, but if the color accuracy is off, you won't see content the way it's supposed to.
We measure color accuracy on a monitor twice: once pre-calibration, only changing a few settings, and a second time after a full calibration. Since full calibrations could cost a lot, it's important to get a monitor with great out-of-the-box color accuracy if you're using it for color-sensitive work such as photo editing.
Color accuracy affects the way you see every type of content. Some people, like professionals, will notice inaccuracies easier than others. Refer to this table to see how the different scores affect who'll notice any inaccuracies.
|Imperfections unnoticeable||Noticeable to professionals||Noticeable to enthusiasts||Noticeable to everyone|
|White balance dE||<1||1-3||3-5||5+|
In monitors that have bad pre-calibration color accuracy, most people will be able to tell. However, post-calibration, almost every monitor can display colors extremely accurately, and even professionals won't spot inaccuracies without the aid of a colorimeter. It's important to know most LED monitors have trouble displaying bright blues, so that's usually the color that is the most inaccurate both before and after calibration.
Do not get mixed up between a monitor's color accuracy and its color gamut. A color gamut, whether in SDR or HDR, tells us what range of colors a monitor can display, and its color accuracy tells us how well it can display those colors.
Before calibration, we measure how good a monitor's color accuracy is. This is important if you don't want to pay the extra money to get your monitor calibrated. The overall score depends on the white balance dE and the color dE.
The color accuracy isn't measured right out of the box, but rather we change a few settings to get the most accurate picture first, and sometimes these different settings result in a better picture than its default settings. Here are a few changes we make:
Note that results vary from unit to unit of the same model due to panel variances, or you might have personal preferences, so adjust these settings how you like.
We measure the monitor's color accuracy post-calibration, and it's measured the same way as it was before calibration. This score shows you how accurate the colors are after a full calibration, but most monitors have more or less the same results here, so it's not a very important score. Find out how to calibrate your monitor here.
We calibrate the monitor using the same picture setting we measured with in pre-calibration. Here are a few steps in the process:
After calibration, we remeasure color dE, white balance, and gamma. The software isn't perfect, and sometimes we have to adjust some values manually to get the most accurate image possible.
Simply put, color dE measures how inaccurate the colors are. We measure how well the monitor can reproduce different colors, with a 75% stimulus at points of 20%, 40%, 60%, 80%, 95%, and 100% saturation for each color. The final dE is the average of all inaccuracies at different points, and it's measured before and after calibration. Virtually no monitor can have a dE of 0, and most people will only start noticing inaccuracies if the dE is greater than 3, so don't worry if your monitor has some inaccuracies.
The above graphs are from the ViewSonic Elite XG270QG before and after calibration. It has bad out-of-the-box color accuracy, but post-calibration, its color dE is similar to most monitors and any inaccuracies aren't visible to the human eye.
Color temperature also affects color dE. A cold color temperature, which is above the target of 6500K, gives colors a blue tint, while a warmer temperature - below 6500K - means colors have a red/yellow tint.
White balance dE measures how a monitor can display different shades of gray, which range from white to black. We test 10 different shades of gray, from 10% (almost black) to 100% gray (white) at increments of 10%, measure the dE from each test, and find the average of all of them. Each shade is displayed on an 18% window on the screen, and like with the color dE, the lower it is, the better.
In the grayscales above, you can see how a bad white balance dE (left) looks like versus a good one (right). The picture on the left has visible red banding in the 70% and 80% shades of gray, and this affects the overall picture quality and color accuracy of all colors.
Note that since we measure 10 specific shades of gray and measure their dE, any other given shade of gray that we don't measure, for example, 37%, might have a dE different from the average dE.
Gamma is the brightness, or luminance, of different shades. This is measured at the same time as a monitor's white balance dE and doesn't affect the overall pre-calibration and post-calibration score, but still has an effect on the overall image. Gamma is supposed to follow a target curve, and when followed properly, scenes are displayed at their proper brightness. So that means if you're watching a video and there are shadows, you'll see those shadows as the creator intended. If it's above the target, it's too dark, and you might not see details on those shadows. If it's below the target, it's too bright, and those shadows won't appear as they're supposed to.
Unlike color dE and white balance dE, it's a lot easier to spot errors in gamma. The target is 2.2, and most people can start noticing differences if it drops below 2.1 or higher than 2.3.
The gamma graphs above are from the LG 32UD99-W. In the pre-calibration picture, dark scenes are too dark, and bright scenes are too bright. After calibration, it follows the target very well, although it's not perfect as some bright scenes are slightly too bright.
For both white balance dE and color dE, dE is a calculation in the difference from the displayed color and the target color. You can see the exact calculation, dE2000, here. If there are no inaccuracies at all, the dE would be 0, but as mentioned before, it's almost impossible to have a perfect score, so our target is to have a dE under 0.5. Even at this difference, no one will be able to spot inaccuracies without the aid of a colorimeter.
Like any test or measurement, it's not perfect. We all see colors differently and our eyes perceive differences in unique ways. If the color red has an inaccuracy on a monitor, one person might see it as being closer to pink, while another might see it closer to orange. These differences are subjective, but our tests provide a mathematical, objective, measurement.
To get the most accurate colors as possible, you'll need to pay extra for a full calibration. These could get costly, and might even cost as much as the monitor itself, as some at-home kits could cost more than $250. Changing the picture mode and adjusting the brightness levels to your liking should be good enough for most people.
When a monitor is calibrated, the software you use most likely will save a calibration file that ends in .icm. It essentially tells your computer how to accurately display content on your monitor, and macOS computers do a better job of applying it than Windows. For each of our monitors that we test, we provide the ICC profile that you can download, but it's provided for reference only and shouldn't be used, as the calibration values vary per individual unit even for the same model due to manufacturing tolerances. Learn how to calibrate your monitor here.
Color accuracy tells us how well a monitor can display colors and shades. Whether you're a photo editor or simply sitting back to watch your favorite videos, color accuracy is important and you want to view content as the creator intended. We measure the color dE, white balance dE, and gamma before and after a full calibration, but since full calibrations are costly and produce similar results between each monitor, the pre-calibration score is more important. Most monitors we've tested have at least decent out-of-the-box color accuracy, and only a handful have produced seriously inaccurate images.
It's important to remember color accuracy differs from monitor to monitor, even if they're the same model because of manufacturing differences, so the results on our unit might not be the same as your unit. Also, how one person sees any inaccuracies is different from how someone else might see it.