The Accessibility feature Black on White in Settings > General > Accessibility will do this in a more colorful way for the entire iPad display.Īn ePub or most other ebook formats are just a collection of text and files with tags to suggest layout. It converts to grayscale and then inverts the image so that the text is white on a black background. PDF Expert does have a Night display mode. You'd need a PDF editor to change something like the background color. Most PDF readers, all that I know, are concerned with an accurate representation of the file. It is in the nature of a PDF file to contain all the necessary information to print, and because of this things like background color are embedded in the file. I don't know of any PDF reader that will let you do this.
You can't change the background color of a PDF in iBooks.
