Invert the colors of a PDF
Inverts the colors of every page of a PDF, like a photographic negative: the white background becomes black and the black text becomes white. Useful for creating a "dark theme" version of a document or for saving ink when printing on a dark background.
How it works
Each page is first rendered as a high-resolution image (using the pdf.js rendering engine), then each pixel has its red, green and blue components inverted (255 minus the original value). The inverted pages are then reassembled into a new PDF, one image per page.
Does the text remain selectable after inversion?
No. Because the inversion happens at the pixel level, each page becomes an image: the text can no longer be selected or copied in the output PDF, unlike in the original document.
Is the result the same as a PDF reader's dark mode?
Visually similar, but baked into the file itself: unlike a dark mode enabled in a reader app, the inversion here is applied once and for all and is visible in any reader, including when printing.
Page rendering and inversion happen entirely in your browser (pdf.js for rendering, WebAssembly for reassembly) — your PDF is never sent to a server.