How much color gamut do displays really need? Part 3: Existing color gamut standards

Jul 23, 2013
Author: Jeff Yurek

Last week I looked at the three "P's" of human color perception– physical, physiological and psychological– as a way to help define a color gamut for the ideal display. Based on real world examples from art and commerce, I concluded that the range of colors found in nature, as measured by Pointer, provided the best fit with our two design goals which were an accurate and exciting, immersive experience. This week, I'd like to get a little more practical and take a look at existing color gamut standards to see what we might realistically be able to achieve today.

What fits best?

Color gamut of 4,000 surface colors found in nature as measured by Pointer in 1980 against the color gamut of the iPhone 5.

The first thing you'll notice about Pointer's gamut (pictured above again) is that it's a pretty odd, squiggly shape. This means it is going to be difficult to cover efficiently with a three primary system that mixes just red, green and blue to create all the colors we see, like the LCD found in the iPhone. In order to cover Pointer's with just those three colors, we'd need to make them extremely saturated. There are proposed standards that take this  approach, such as rec.2020, but since they are not practical to implement today from a technology standpoint I've decided to ignore them for this discussion.

For the near future, we'll need to rely on just three colors to get the job done, so what can we do now? Let's look at two popular wide color gamut standards: Adobe 1998 and DCI-P3:

Current wide color gamut standards Adobe RGB 1998, commonly used by pro photographers and designers, and DCI-P3, used in digital cinema, compared to Pointer's gamut in CIE 1976

Let's start with Adobe 1998. Many people are familiar with this color gamut since it is found as an option on many consumer cameras and it is popular among creative professionals. It certainly covers a significantly wider range of colors than the HDTV broadcast standard with a very deep green point. The rich cyans that we talked about in the movie "The Ring" would look great in Adobe 1998. But, we’re not getting any more of those exciting reds and oranges. In fact, Adobe's red point is identical to the HDTV broadcast standard.

What about DCI-P3 then? Designed to match the color gamut of color film and used in cinemas all over the world, DCI-P3 has a very wide gamut. The reds are particularly deep and, of course, all of the colors from the movies we looked at are covered. Still, it's missing a lot of the deep greens found in Adobe 1998 and only just fits the green Pantone color of the year. So DCI-P3 is not quite perfect either.

What about a hybrid, custom gamut? 

What if we combined the green from Adobe with the red from DCI-P3 and their shared blue point? We’d end up with pretty good, high 90’s percentage coverage of Pointer’s gamut, coverage of all of the existing HDTV broadcast content, full coverage of cinema content from Hollywood and a superior ecommerce experience with most of the colors from the natural world covered.

Hybrid color gamut standard that combines the green point from Adobe 1998 with the deep red of DCI-P3

Looks pretty great and we can make displays now that cover this color gamut with today's technology. But how would it work on the content side? Would we need to get together and agree on this new standard and then wait for years while it is slowly adopted by content creators and display makers?

Next week

Next week we'll look at how content delivery might evolve to support gamuts like this without the need for major changes to broadcast standards.