4413217e_mera_modes_for__anyway____CNET__Description
[Mode] Documents, aka Text [Uses] Anything you might otherwise have scanned or photocopied, like business cards and book pages, as well as signs with information you want to remember, like phone numbers. [Description] 
This is typically a black-and-white mode with extra contrast and sharpness applied, optimized for readability. Some variations on this mode also include some lens-distortion correction.
What are all those camera modes for, anyway? - CNET