[matrss]

I don't have an iPhone, but on Android there is the "Paperless Mobile" app (https://github.com/astubenbord/paperless-mobile), which can be used to scan as well. There are just some documents that I would prefer to have in proper and consistent "document scanner"-quality; I am always having a hard time with lighting using those phone scanners (although Paperless Mobile is one of the better ones I have used).

[westurner]

Would a document capture camera with a [ring] light also work?

[matrss]

Those still have the speed disadvantage of a phone camera and need more space than a compact document scanner, I'd imagine. I guess a ring light for my phone would be an improvement; using the builtin flash usually leads to very uneven lighting in the scan.

[westurner]

IIRC there are certain models of sheet-fed duplex scanners that work with Linux (with e.g. a lower-wattage Pi)