Nick Heer on Liquid Glass:
iOS’s system theme was not branded from when it was first shown in 2007.
it is not the first time Apple has used the term [“Liquid.”] Since 2018, it has described high-resolution LCD displays with small bezels and non-zero corner radii — like the one on my MacBook Pro — as “Liquid Retina displays”.
Apple is emphasizing another defining characteristic of the Liquid Glass design language, which is that each part of the visual interface is, nominally, concentric with the bezel and corner radius of a device’s display.
[The Liquid Glass] is as much a reflection of the intent of Apple’s human interface designers as it is a contemporary engineering project, far more so than an interface today based on raster graphics. That it is able to achieve such complex material properties in real-time without noticeably impacting performance or, in my extremely passive observations, battery life, is striking.
Apple also tries to solve legibility by automatically flipping the colour of the glass depending on the material behind it. […] If Apple really wanted to improve the contrast of the toolbar, it would have done the opposite. […] It is Apple’s clever solution to a problem Apple created.
It seems Apple agrees [corner radius] is more appropriate in some apps than in others — app windows in System Information and Terminal have a much smaller corner radius.
Even on a device with four rounded display corners, this dedication to concentricity is not always executed correctly. My iPhone 15 Pro, for example, has corners with a slightly smaller radius than an iPhone 16 Pro. The bottom corners of the share sheet on my device are cramped, nearly touching the edge of the display at their apex.
In a column view in Finder, for example, there is a hard vertical edge below the rounded corner of the ostensibly floating sidebar. I am sure there are legibility reasons to do this but, again, it is a solution to a problem Apple created.
It could simply be an exercise in branding. Apple’s operating systems have shared a proprietary system typeface for a decade without it meaning anything much more than a unified brand. And it is Apple’s brand that supersedes when applications look the same as each other no matter where they are used. In my experience so far, developers that strictly adhere to Apple’s recommendations and fully embrace Liquid Glass end up with applications having little individual character.
So far, Apple justifies this redesign, basically, by saying it is self-evidently good for all of its platforms to look the same. This is an inadequate explanation, and it is not borne out in my actual day-to-day use.
[O]n today’s hardware that is, to me, less of a showcase for Apple’s visual design cleverness and more of a means to get things done.