Some users notice more blooming on the 12.9-inch iPad Pro's Liquid Retina XDR mini-LED display than expected, but the effect should be minimized.
According to recent published According to Apple support documents, the iPad Pro's Liquid Retina XDR display was designed to "improve the compromises of typical local dimming systems, where the extreme brightness of the LEDs can cause a slight blooming effect." According to this, the effect should have been minimized.
The Liquid Retina XDR display improves on the compromises of typical local dimming systems, where the extreme brightness of LEDs can cause a slight blooming effect because the LED zones are larger than the LCD pixel size. This display is engineered to deliver crisp front-of-screen performance with its incredibly small custom mini-LED design, industry-leading mini-LED density, large number of individually controlled local dimming zones, and custom optical films that shape the light while maintaining image fidelity and extreme brightness and contrast.
iPad Pro XDR display: Users notice more blooming than expected
Nevertheless, some iPad Pro owners are noticing more blooming than expected and are sharing their experiences on social media. Thanks to the use of mini-LED display technology, the iPad Pro has 2,500 local dimming zones. Local dimming allows some areas of an LED screen to be dimmed almost to the point of darker, true-to-life blacks while preserving the bright parts of the screen. The technology can significantly increase the contrast ratio of images and enable the intense highlights of HDR content. On a display with local dimming, if one zone is illuminated and an adjacent zone is not, an artifact can occur towards the part of the screen that becomes brighter than the adjacent zone, known as "blooming."

Rumor has it that Apple wants to switch to OLED
OLED displays, such as those used in the iPhone 12 range, do not require local dimming as they are able to turn off individual pixels to achieve true blacks, all without the blooming effect. Local dimming can be a way to achieve image quality that comes close to that of OLED displays, but it is difficult to achieve the same contrast. Blooming on the new 12.9-inch iPad Pro is therefore to be expected to some extent. But users seem to be divided on how bad the effect actually is. Although mini-LED display technology is expected to be used in the new MacBook Pro models, other rumors suggest that the company wants to use OLED displays for iPad and MacBook devices from 2022. (Image: Apple)