Display Technology & Calibration – What stays the same and what will change for mastering 4k and 8k UHD media

Download MP3 of interview with Charles.

Download transcript of interview with Charles

I had two goals with this podcast:

1. Have a one-on-one conversation with Charles Poynton about the future of display technology as we evolve from mastering HD to UHD, 4k and even 8k media.

2. Understand where display calibration technology stands with mastering displays (LCD and OLED in particular) and what is state of the art with calibration software.  A point I wanted to bring out was that mastering displays for high-end productions will always need calibration tools for mastering purposes, but how can a growing market of digital creatives leverage these tools to bring their iMacs and personal computers into close compliance with Rec.709 and and newer standards using ICC profiles?  The amount of content this community is mastering is huge, so can they use the same calibration tools?

From our conversation it was clear that Charles has a great deal to say about displays and display technologies because he’s been an instigator of many display standards since the 1980s.   Charles really pours on the insights in this interview, so I’m delighted to be passing this along to my community of listeners.

Questions:

1. Charles – you have been instrumental in defining standards for display technologies since the ’80s. I don’t think I could even begin to summarize them so I’m going ask you for the key ones you feel were important. Seems like this would set the stage for our conversation.

2. The title of this conversation is “display technology and display calibration – What stays the same and what will change as we move into a new world of mastering and displaying UHD, 4k- and 8k-based media”.  Let’s talk about this.

3. Then what changes as we move to mastering  higher resolution displays with 8-, 10- and 12-bit content?

3a. Side question: Does the Sony OLED use a different white point?

4. What is the future of OLED displays? Will they ultimately provide a wider color gamut for future SMPTE UHD standards?

5. SpectraCal released a significant update to CalMAN 4.8 for display calibration. What do you think of their algorithms for use with 8-, 10- and 12-bit mastering of video content?

6. Do you think ICC profiles are accurate enough to master Rec.709 video content in general?

After our podcast I reached out to SpectraCal for more information about their CalMAN RGB software, which creates highly accurate ICC profiles for digital creatives.  As Charles says in the interview, most companies are not transparent about the technology they create.  However, Charles talks about his knowledge of Adobe’s use of ICC profiles for precision color work in After Effects.

My experience with SpectraCal is they are extremely transparent with their product technology. In fact, they encourage you to ask questions so they can help you understand. I asked SpectraCal exactly ‘how’ their software builds ICC profiles and how similar this might be to After Effects’ solution.  Here is what I learned from Joel Barsotti, Director of Software Development at SpectraCal: In regards to bit depth with ICC profiles, the actual profile itself is the biggest bottleneck.

The primary storage format is an s15Fixed16Number, which is a 32-bit number that uses the first 16 bits to encode the sign and the whole numbers from -32,768 to 32,767, and the second 16 bits to encode the remainder as n/65,536.  Tone response curves are stored as uInt16Number entries, meaning they are integer values 0-65535.  Both matrix and 3D LUT data use the s15Fixed16Number to store the XYZ data.

In CalMAN all measurements are stored as 64-bit floating point values and processed that way until the last possible moment, when we convert it to the formats ICC requires.

So to summarize: SpectraCal’s CalMAN RGB creates an ICC profile with the highest level of mathematical accuracy available, and this is not what you might expect from the old days of ICC profiles that used only 8 bits of accuracy.  Setting aside any observed metamerism differences for displays on your desk, the ICC profiles from CalMAN RGB can be extremely close to Rec.709, at least to my eyes.  Now you have to keep in mind a low-cost LCD monitor is not going to have the quality you want in color accuracy, and black levels in particular. But at least you know after running CalMAN RGB and CalMAN Color Checker where the monitor is off. That, in my mind, is better then simply not knowing.  If you’re mastering content on your MacBookPro or an iMac for a movie going to a festival or color grading VFX work where color matching is critical, then consider purchasing an LCD or OLED reference monitor.  You’ll know when it’s time to make that change.

As I say in the interview, I have a Flanders FSI display sitting next to a 2-year-old iMac, and frankly they look nearly identical when I’m using DaVinci Resolve for color grading (after I completed the CalMAN RGB calibration process using 65 points). The Flanders is a ~$5000 color reference monitor specifically designed for mastering video content.  I’m not suggesting people do not need references displays. You do, and in fact I’m a big fan of Flanders’s LCD reference displays.

The point here is that now your video production creation and approval workflow can work more smoothly, knowing everyone in your shop can use a monitor that is at least very close to Rec.709 and know which ones to not trust if they don’t calibrate well due to low quality. The client will be happier, too, and you’ll spend less time (if any) explaining why this display looks different from the other one. You’ll gain more trust in your work and with your clients.

Hope you enjoy the interview with Charles Poynton.  He’s an amazing resource for understanding display technology now and where it’s going in the future.  If you’re into the details of display technology I recommend getting his book. And be sure to check out this blog at Charles Poynton Blog

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TomParish.com Colorist

ISF Level II Display Calibration Specialist
Executive Producer – Social Media  and Thought Leadership Content
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