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?
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:
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.
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 we’ll look at how content delivery might evolve to support gamuts like this without the need for major changes to broadcast standards.
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This is an interesting idea which, based on the owner of this blog, I’m guessing is achievable with quantum dot film. Since full Rec. 2020 color space coverage will probably require laser projectors and/or OLEDs, this is a decent interim step.
Personally, I’d prefer the green point to be a bit further out. When using the green point of AdobeRGB, your Hybrid Adobe-DCI color gamut will have 100% coverage of AdobeRGB but only ~99% of DCI-P3. By moving the green point out a bit, we could have 100% coverage of AdobeRGB and 100% coverage of DCI-P3 making the monitor perfect for all kinds of content creation.
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Interesting article. Covering the entire Pointer’s gamut becomes a lot easier by the way when using a color system with more than three primary colors. Sharp already has HD-TVs with RYGB primaries on the market for a couple of years (Sharp Aquos Quattron models) and showed a 60.5″ TV with RYGCB on SID 2009 with over 99% coverage of the Pointer’s gamut (http://sharp-world.com/corporate/news/090529.html). There are also multiple papers around discussing displays with 6 primaries.
Displays with perfectly monochromatic primaries should be just around the corner too. At least with red and blue/violet. Even some conventional TFT LCD’s with B+RG LED, GB-R LED or RGB LED backlighting already have nearly monochromatic red and blue primaries. The Samsung SyncMaster S27A850D S-PLS display for instance, with a red primary very close to 610 nm and blue also quite close to 462 nm. And there have already been OLED-like prototype displays based on lasers, resulting in monochromatic primaries.
Combining those two would make it possible to display nearly every visible color, even the purely additive colors, that can only be produced by a light source and cannot be reflected off any surface. If you optimize for coverage of the entire CIE 1931 xy chromaticity diagram you can reach 73.84% with 3, 86.68% with 4, 92.54% with 5 and 95.49% with 6 primaries. If you optimize for CIE 1976 u’v’ you can reach even higher coverages.
One question, do you have the Pointer’s gamut as raw data in CIE 1931 xy or CIE 1976 u’v’ coordinates in Excel, Matlab, CSV or TXT format? Because I would love to have those for making plots and calculations myself.
yw，I also want to have that Pointer’s gamut raw data. That would be helpful to make calculations.
You can find the data at http://www.cis.rit.edu/research/mcsl2/online/PointerData.xls. That’s the same file Jeff sent me.
The boundary of the Pointer’s gamut is in DF9:DG45 on the Calculations sheet
Speaking of color gamut standards, how do you think about BT.1361 and xvYCC(IEC 61966-2-4)? The former one doesn’t seem to have products to support it, while there are some products claiming support the latter standard.
Both of those standards are interesting and, you are right, there are some devices on the market that support xvYCC today- especially on the capture side. However, I think we’ll see the industry move to a gamut like DCI-P3 first since there is a lot of existing content to take advantage of (http://dot-color.com/2013/07/23/how-much-color-gamut-do-displays-really-need-part-3-existing-color-gamut-standards/). Beyond that we are looking at truly next-gen color gamuts like rec.2020 or XYZ Color Space. See: http://www.youtube.com/watch?v=x0-qoXOCOow or http://movielabs.com/ngvideo/MovieLabs%20Specification%20for%20Next%20Generation%20Video%20v1.0.pdf
I’m using color think Pro to analyse some images as compared with the Standard gamuts (sRGB, ProPhoto, Adobe 1998). Unfortunately, Color think Pro is missing DCI-P3 profile, and therefore I can’t compare my images with respect to the DCI-P3 in the Lab or xyY colorspace, I mean in 3D.
Could you please point me to any source from where I can get DCI-P3 profile (.icc) or the characterization dataset that can be used to create DCI-P3 profile?
Unfortunately don’t have any .icc dataset for DCI-P3 either. I would also love to see something like this. Comparing these spaces in 3D is definitely the way to go. Please let me know if you come across something!
Here you go: https://db.tt/HB5sOqLm
Not sure where I got it from, but I’m guessing it’s either the Adobe Creative Suite Master Collection or the X-Rite i1Publish Pro kit. By the way, you can find your profiles in “C:\Windows\System32\spool\drivers\color” (on Windows).
If you want to make your own profile it’s a bit harder, because you have to convert the CIE 1931 xy primaries to XYZ primaries (easy so far) and then do a chromatic adaption to D50 (that’s the most common profile connection space illuminant), but I’m not sure what the starting point of that chromatic adaption should be (I’m guessing the DCI-P3 white point).