AR: An unnecessary and not reliable product.
In your opinion.
Explain this:


The ADC isn't measuring anything. It is taking two or three bits of information:
1. The color that an application is actually outputting to a pixel. i.e. an RGB level.
2. The colorspace that the app says should be used for that pixel for ColorSync to correctly display it. It defaults to sRGB if the app doesn't specify.
3. The ICC profile associated with the display as seen in the screen capture above.
Then given those bits of information, it can calculate via ColorSync what that particular pixel should be if you were to measure it with an external device, and all of the color transforms, profiles etc. are correct.
So it is sometimes useful if you really know what you are doing, to make sure that all your profiles are in order if you can measure patches with an external sensor.
It doesn't really do anything to validate anything
without an external sensor, other than to verify numbers are what they
should be.
It's "interesting" to see the various calculations that it can do, but there are a lot of assumptions and pitfalls along the way. For one, an application can bypass ColorSync and use it's own CMS.