Hi All,
While this isn't the entire story, as it can get very complex, I would like to share a bit of knowledge regarding how Apple's Color Management functions today. Additionally, we were able to calibrate the MacBook Pro w/XDR Display and have included some data. (spoiler: the display calibrates extremely well). Please keep in mind that while we provide data for SDR @ Rec.709 and HDR @ P3, there are many color management targets and scenarios with their own idiosyncrasies that may require consideration.
The Mac is able to display multiple windows that may have different color spaces (targets); as such, it is important to 'manage' the system so that a window (or app) that may be in the sRGB color space will be accurately represented next to another window in a different color space such as Rec.709 or Adobe RGB. To do this, the display profile would inform the color management system as to how the connected display is optimized; at which point, the OS will transform the various color spaces for representation on the target display. In content production, this is similar to applying a LUT (Lookup Table).
sRGB (source) > Apple Color Management > P3-D65 display
In the above scenario Apple Color Management will take an application in sRGB and transform it into the P3-D65 color space. Where this becomes tricky is when a display is unable to fully represent the color space of the source. For example, currently available displays are not quite capable of hitting the Rec.2020, ST.2084 HDR standard-- the standard has a larger color volume and a higher max nit level at 10,000 nits. Apple's specification for the MacBook Pro XDR Display only achieves 1,600 nits. When this happens, some form of tone mapping occurs in an effort to accurately represent the entire image without blowing the highlights out. We can go down a very large rabbit hole with this.
In terms of the MacBook Pro XDR, we found the out-of-box measurements to be quite good on the sample tested; of course, there may be manufacturing tolerances where one may be further off, but overall the display wasn't terrible. Thankfully, Apple provides the 'Fine-Tune Calibration' in order to accommodate for out-of-the-box variables and drift over time.
Using the '
Patterns Test Generator' available on the Mac App Store (disclosure: we are involved in this app), and the
Calman Ultimate Calibration Software (we are not involved in this app), we tested various color spaces and how Apple's Color Management handles them.
The data attached was taken after both display warm-up and a Fine-Tune Calibration.
SDR
- MacBook Pro XDR set to the 'HDTV Video (BT.709-BT1886)' Preset.
- Patterns Test Generator set to tag patterns (content) as 'BT.709 @ BT.1886'
HDR
- MacBook Pro XDR set to the 'HDR Video (P3-ST 2084)' Preset.
- Patterns Test Generator set to tag patterns (content) as 'Tone Mapped HDR (P3 @ ST 2084)'
We have provided three charts for each SDR and HDR. They are:
Grayscale-EOTF
This chart measures the grayscale from 0% (black) to 100% white. Here we are looking for the RGB Color Balance to line-up on top of each other and for the response curve (EOTF) to track the yellow line. There are two quantifications of error included-- DeltaE 2000 and DeltaE ITP. DeltaE 2000 is most commonly used with SDR content and Delta ITP is most commonly associated with HDR content; however, a truly accurate monitor will have low numbers on both. ?
Saturation Sweeps
This chart tracks color saturation at 25%, 50%, 75%, and 100%. While many reviewers like to only measure 100% to see how far out the primaries can go, the reality is that very few colors are actually at 100% saturation. The sweeps provide a way to validate if the signal is being mapped into the proper color space.
Color Checker
While the grayscale and saturation sweeps provide quality data, they don't provide any data outside of the primary and secondary colors. To achieve a more well rounded image (pun intended) of how the system is performing a color checker chart provides an quick and efficient way to further test the system. Of course, we could even go further and measure larger datasets of the color volume, but for now these will suffice.
Summary
As the results illustrate, the Fine-Tune Calibration is an effective way to dial in the MacBook Pro XDR display. Please note that while we are evaluating color balance, color space, response curves, we are not evaluating local dimming, blooming (halos) and other things that contribute to what is called a 'reference display'. After all, color calibration is only part of the battle to quality images.
Best,
David Abrams