So bright
March 12, 2019 1:44 AM   Subscribe

This is something I've always wondered but never been able to Google successfully. Why do (some?) smartphones have a bright white, max brightness startup screen? My iPhones did it, and so does my Pixel 2. Rather jarring, especially in the dark.
posted by cozenedindigo to Computers & Internet (5 answers total) 1 user marked this as a favorite
When a computer first starts, there is a tiny (really tiny) program called a "bootloader" or BIOS that has the job of connecting to the main storage and loading the main O/S. (more on wikipedia).

The bootloader needs to be kept as small and as simple as possible, because it needs to be stored in special memory and that memory is expensive and not used for anything else.

My guess would be that dimming the screen during the initial bootloader phase was seen as extra work and unnecessary for the job of loading the O/S, so the programmers didn't bother.

Perhaps some phone designers agree with you that this is jarring, so have put in extra work on some phones to dim the screen in this phase. Perhaps this is not so easy on an iPhone or the iPhone designers did not consider it a priority.
posted by richb at 3:50 AM on March 12 [3 favorites]

I just tried this on my iPhone and it doesn’t seem to be the case any more (there’s a white apple logo on a black screen), so maybe they changed it. In any case, maybe part of the reason they don’t see it as a high priority is that they don’t expect people to fully power off their phones regularly?
posted by Bloxworth Snout at 4:36 AM on March 12 [1 favorite]

The iPhone startup screen matches the iPhone's color: black iPhone = white logo on black background, silver iPhone = black logo on white background.
posted by Ian Scuffling at 5:18 AM on March 12 [4 favorites]

More generally, why the opening screen tends to be super bright and colorful, is this is the first screen a new consumer will see, and they're trying to make a vivid impression. Additionally it's assumed one is powering on in store, where there's likely an excess of overhead lighting. It's similar to TV's being configured in "display mode" at electronics stores with settings no one should be running while at home.

As other's point out, the bootloader needs to be simple, so it will run at X brightness. Because of the above conditions manufactures will prefer to run at 100% instead of 50% or 1% when choosing that X brightness.

I'll note that many custom roms, which don't need to depend upon "consumer first impression" tend to have an opening boot screen which is mostly black with a colourful logo/animation instead of full screen colour like most manufacturers.
posted by nobeagle at 6:31 AM on March 12 [1 favorite]

Makes sense. Thanks folks!
posted by cozenedindigo at 6:42 AM on March 12

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