Invert PDF Colours
Make a dark-mode, sepia or greyscale copy of a PDF for comfortable long reading.
Recolouring runs entirely on your device. Papers and internal documents are rendered locally and never uploaded.
Shrink the recoloured file
About Invert PDF Colours
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 — A dark page compresses worse than a white one, and the vector text has been replaced by pixels.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.
All ArrayKit tools