Adjust Brightness… (CmdAdjustBrightness) and Adjust Contrast… (CmdAdjustContrast), both in the command palette, open a dialog with brightness and contrast sliders from -100 to 100, applied to the rendered pages with a live preview. It works for fixed-page documents (PDF, DjVu, XPS, comic books, images) and makes poor scans easier to read. The values are remembered per document (Brightness, Contrast in FileStates). The sliders work with the keyboard: their label’s access key focuses one and the arrow keys change it (#4788).

Fixed-layout EPUB chapters (a viewport with width and height) are laid out as exactly one page at the viewport size, without margins, instead of spilling onto blank extra pages. Text placed with CSS transform (as in InDesign exports) is drawn at its intended size and position (#1293).