A white page is a floodlight in a dark room, and most PDF readers either cannot invert a document or invert it only while you are looking at it. Making a genuinely dark copy means recolouring the pages themselves, which is what this tool does. Every page is rendered, each pixel is inverted, and the result is written back as a new PDF that stays dark in any reader, on any device, including e-ink. Sepia goes a step further by warming the inverted result so it reads like a lamp-lit page, and greyscale simply drains the colour — handy when a document is destined for a monochrome printer.
Features
True inversion: white pages become dark and stay dark in every reader
Sepia mode warms the result for long, comfortable reading sessions
Greyscale mode for monochrome printing and for reducing distraction
Resolution choice from 108 to 216 dpi, trading size against sharpness
Live thumbnails of the recoloured pages before you download
Page sizes preserved exactly, so the document still prints correctly
Handles long documents, up to 80 pages in one pass
How to use the Invert PDF Colours
Drop the PDF onto the page
Pick dark mode, sepia or greyscale and watch the thumbnails update
Raise the resolution if small type looks soft
Download the recoloured PDF
Example
Input
textbook-chapter.pdf — 22 pages, black text on white
Output
A 22-page PDF with near-black pages and light text, at the same page size.
Diagrams invert along with the text, which usually reads better than it sounds.
Common errors & troubleshooting
The text is no longer selectable. — Recolouring works pixel by pixel, so the pages become images. Keep the original for searching and copying, and use the dark copy for reading.
Photographs look strange after inverting. — Inverting a photograph turns it into a negative. Greyscale is the better choice for documents with real images, or crop them out first.
The dark version is much larger than the original. — A dark page compresses worse than a white one, and the vector text has been replaced by pixels. Lower the resolution, or compress the result.
Small print looks blurry. — Raise the resolution to 216 dpi. The trade is file size — at that setting a long document gets noticeably heavier.
Frequently asked questions
Why not just use my reader's night mode?
Because it only applies while that reader is open. A recoloured file stays dark on a phone, a tablet, an e-ink device and anywhere you send it.
Is the document uploaded to be recoloured?
No. Rendering and recolouring both happen in this tab, so research papers and internal documents stay on your device.
Does inverting save battery?
On an OLED screen, noticeably — dark pixels draw far less power. On an LCD it makes no difference to battery, only to comfort.
Can I invert only some of the pages?
Every loaded page is converted. Extract the pages you want first, invert those, and merge them back if you need a mixed document.
Is sepia better than plain inversion?
For long reading sessions, many people find it easier — pure white-on-black can shimmer. Try both on a page of your own text and see.
Related tools
PDF to Images — Render PDF pages to PNG or JPG images you can download.
Compress PDF — Shrink a PDF by re-rendering each page to a JPEG at a chosen quality and resolution.
PDF Read Aloud — Listen to a PDF read out loud, passage by passage.
Crop PDF — Trim margins from every page via the crop box.
Resize PDF — Rescale every PDF page to A4, Letter or another standard size, content centred.
Image Filters — Apply grayscale, sepia, contrast, blur and more, then export the PNG and the CSS.
PDF to ZIP — Export every page as its own file inside one archive.