paperColor property
Colour of the paper: behind each page until it is rendered, and on the back of a turning sheet in single-page mode.
Match it to how white looks on the page after colorFilter: white with no filter (also in a dark app theme), dimPaper with dim, sepiaPaper with sepia, nightPaper with nightMode. A mismatch shows as a wrong-coloured back while a page turns, for example a black flap on white pages.
This is not the screen background around the book; set that on the
parent (for example Scaffold.backgroundColor).
Implementation
final Color paperColor;