iPhone 12 screen

Hello pincheng,

We're happy to help with your iPhone 12 screen no longer being dark. First, you can check and adjust the brightness using the steps here:

Adjust the brightness on your iPhone, iPad, or iPod touch

Next, you can make sure Dark Mode is enabled following the steps here:

Use Dark Mode on your iPhone, iPad, or iPod touch

You an also check the Night Shift settings on your iPhone 12:

Use Night Shift on your iPhone, iPad, and iPod touch

Let us know if this helps, or if you have any questions.

Have a great day!

I’ve got similar issues, at night, a dark grey (not black) image looks like this... at about 25% brightness. It seems like a hardware problem.