A colorimeter could be used to calibrate a screen's colors, including a TV. I'm not aware of such a device for touchscreens though. The touchscreens I replaced

A colorimeter could be used to calibrate a screen's colors, including a TV. I'm not aware of such a device for touchscreens though. The touchscreens I replaced via iFixit were each good enough replacements. But to be fair: I never did drawing on them. Regarding the issue, I find it pretty simple to address: I believe Apple should allow third party repair shops to achieve such, and if they're unwilling or unable to, they should by law be forced to do it themselves for free, with S&H on them, too.