Computer Displays: What Is Color Space?
Computer Displays: What Is Color Space?
We all know colors are made of three primitive colors – red, green and blue. Mix them in some ways and you get different set of colors that your eyes perceive, and monitors work in similar ways to display the correct colors to viewers. However, not all reds, greens and blues are created equal, and the green color you’re seeing right now in your display may end up looking different in someone else’s computer. Why is it so?
Understanding Colors
Image: James Webb Space Telescope Blog (webbtelescope.org)
First things first, how do we even know which type of red is the “most red”? It’s fairly simple: by measuring the wavelength of the light. The colors we see have different wavelengths, ranging from 380 nanometers (violet) to 740 nanometers (red). Each color has its specific wavelengths, anything below is what we call ‘Ultraviolet’ (UV), while anything above is referred as ‘Infrared’ (IR) – both of which are invisible to the human eye. (Tip: cameras however can see IR in some ways. Try pointing your camera to proximity sensors such as iPhone’s FaceID array.)
The tools that measure wavelength is what we call spectrophotometer/colorimeter, such as Datacolor SpyderX. Some high-end professional monitors do come with such tools to allow users to calibrate colors as needed, and usually that needs to be done once in few months to maintain consistent color quality.
Image: Datacolor
Mainstream Color Standards: sRGB & DCI-P3
To make sure everyone is on the same page when it comes to colors, various industry bodies agreed on a set color standard and develop their hardware and software with those standards in place. The most common color standard right now is sRGB – virtually every type of media on the Internet follows this color space standard. sRGB standard was published in 1999, and is practically the de facto standard for all things color, unless another color space is specified (through embedded color profile, for example).
Most computer displays follows the sRGB color standard, however some low-end displays does not fully reproduce the entirety of its colors. You may notice these displays are listed as ~72% sRGB or 45% NTSC (another color standard introduced way back in 1953, however it’s largely obsolete). Other high-end displays meanwhile can be seen listed with “100% DCI-P3” or in some cases even “Adobe RGB”.
CIE 1931 Chromaticity Diagram – color wavelength labeled along the edge of the color spectrum. Image: Wikipedia
However, sRGB isn’t perfect. Human eyes can see a lot of colors, and are especially sensitive to green. sRGB is far from covering all the green hues, so a new standard is needed to make sure displays can output more colors that actually resembles real life. This chart, called CIE 1931 Chromaticity Diagram, shows all the possible colors visible to humans and the color coverage of various color space standards.
DCI-P3, short for Digital Cinema Initiatives – Protocol 3, is one of the most common color standard in modern displays and TVs. This standard, as the name implies, largely applies to movies and streamed content such as Netflix, though that’s about as far as DCI-P3 go in terms of usage. (Apple uses a variation of it called ‘Display P3’.) Most videos, especially from social media platforms such as YouTube still mainly uses sRGB with a few exceptions. This color space covers more colors than sRGB, though it’s still some distance away from the new ‘holy grail’ of color standards – Rec.2020.
Rec.2020 meanwhile, is still very new, with initial specs published just about a decade ago (in 2012). Rec.2020 covers most part of the CIE 1931 diagram – however, despite all the current monitor technologies, reproducing the full spectrum of Rec.2020 color space is still difficult. No consumer displays (be it monitors or TVs) currently can fully reproduce 100% of the Rec.2020 color space, though some extremely high-end ones get fairly close to it.
The More Colors, The Better?
Not exactly – the more important aspect of computer display is color accuracy. Even if you have a monitor capable of displaying all the colors in the world, a badly calibrated one will be as ineffective as a monitor that can’t produce enough colors in the first place. Some high-end ones will come pre-calibrated from the factory, and for those which didn’t – that’s where colorimeters mentioned above comes in to keep the colors consistent.
If you currently own a 100% sRGB display, should you be concerned? Not really. sRGB remains universal, and that is not getting changed at least in the short-term. You can rest assured that your standard sRGB display can still look good, provided if it’s properly calibrated to display colors correctly. Though, there’s no stopping anyone from jumping to DCI-P3 capable displays since they’re getting ever more presence in both the laptop and monitor markets right now.
