the laminated screen on my iPad Air 2 had that purple looking tint when screen is off, but the screen on the pro 9.7 I just bought is all black when it's off even though it also has laminated screen. Is that normal?
That's the color of anti-reflective coating.
Apple refined their anti-reflective coating throughout these years. Color does not has to be the same. My iPad Air 2 has purple coating. I also see earlier model of 4k iMac had purple coating. My 2016 macbook pro has pinkish reddish coating.If it is the anti-reflective coating as you noted, then why is the OP not able to see the purplish tint on the iPad Pro versus the Air 2? (Which is visible)
Apple refined their anti-reflective coating throughout these years. Color does not has to be the same. My iPad Air 2 has purple coating. I also see earlier model of 4k iMac had purple coating. My 2016 macbook pro has pinkish reddish coating.
The pro uses different materials due to the pencil. This was noted back when the first pro came out. It’s in the keynote if memory serves