More blue or more yellow is not better or worse. For the sake of calibrating the display to DCI-P3, what matters is that the white displayed by the screen match a D65 white point. You may prefer a more blue-ish white point, and it is unfortunate that iOS does not provide a means of color calibrating the display manually or adjusting the white point. We really have no idea what your phones are displaying, and frankly, without a frame of reference it's almost entirely useless to discuss it. What you could do is color calibrate a computer monitor and compare your phone's white point to that, or get a hold of a colorimeter to accurately baseline your assertions about the display quality.
What is expected is that some displays will look different from others due to manufacturing variance and different vendors, and also that displays will change in their characteristics over time. It also appears that the iPhone 6S phones were often more blue in their white points than they should have been, which would skew your perception of what is correct if that was your baseline.
Yes I understand calibration. Im saying there are certain screens that are physically inferior to others. These screens almost have a layer of yellow on them. They will never be as bright, clear, or with the best contrast as the other screens, regardless of calibration. These screens take up more battery, look worse, and are just inferior in all ways. I think this happens because of the bulk of the phones that need to be built for launch. They either runout of good screens, or cant make them fast enough and resort to inferior panels.
Regardless of the calibration, what I really want is the clarity, crispness, and contrast of the "good" screens. I tried to change the 7's calibration using the ios color profiles tool, but it looked artificial and reduced brightness.
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I dont agree. But keep in mind that my argument supports your theory. If the 7 is warmer than the 6s, which according to first graph is too warm, then the 7 is even more warm and farther from 6500 kelvin.
Doesnt really matter if you agree, its a fact that higher # = more blue.
Yellow screens would register as closer or below 6500K. They are incorrect screens.
If you like it, rock it. I havent seen a single person, when presented with the yellow screen vs a clear one, say they like the yellow better in real life.