Negative image on ipad

Open Settings app on your iPad

Tap Accessibility

Tap Display & Text Size

Make sure Smart Invert and Classic Invert are NOT turned on

If your iPad has a Home button, try triple clicking the Home button.

Not sure how to fix this issue IF you own a newer iPad/iOS device without a Home button, though.

If the screen colours appear to be distorted or unnatural, you need to check some key Accessibility settings that are intended to compensate for specific colour-vision issues:

Settings > Accessibility > Display & Text Size

Ensure that all settings enclosed within the red box above are switched OFF/Disabled.

Otherwise, depending upon your installed version of iOS/iPadOS, you’ll need to look at your Dark Mode settings:

Settings > Display & Brightness > [Appearance]