I decided to keep the rightmost one because it í less yellowish than the second rightmost one. Moreover, I checked them again, and the rightmost one does not have any light bleeding while the yellowish one has some slight ligh bleeding around the top right corner (portrait mode). Lastly, it has less book spine shadow effect than the yellowish. Both of them do not have dead pixels or dusts under screen.
So what's your problem?
You don't have to work on both simultaneously.
If they are both uniform, without dead pixels, without color shifting or light bleeding, what's the problem in have a slightly different white temperature calibration on a consumer grade device?
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Your is warmer, but uniform.
I can't see a problem on any of the two iPads showed.
Do you really think that millions of consumer grade displays could be calibrated in the same exact way ? Do you understand that the shift between the two units is, in term of white temperature, minimal ?
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I would keep the one you are calling yellowish, that isn't yellowish but just warmer.
It seems to be the best of the five, and I don't like cold calibrated displays.
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You always try to downplay Apple on every single post you write.
There is no quality control involved here. The displays are all fine and well within production margins.
Screens comes from multiple suppliers/batches and are calibrated as intended for consumer grade use, not photographic professional use (for that people use big monitors with calibration tools for a total value of SEVERAL THOUSAND DOLLARS).