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Adjust PDF Colors
Dark mode, invert, grayscale, sepia, black and white, contrast and color replacement for PDFs.
Free, no uploads, no sign-up. Runs 100% in your browser.
How Adjust PDF Colors works
PDF.js renders each page, the colors are adjusted pixel by pixel on a canvas, and pdf-lib builds a new PDF from the images.
Input: PDF. Output: PDF.
How to use Adjust PDF Colors
- Drop your PDF onto the Adjust PDF Colors area, or click to choose it.
- Wait a moment while page thumbnails render locally.
- Choose the pages and options you need. Previews update as you go.
- Press the main action button and download the finished PDF.
Tips
- Encrypted PDFs must be unlocked first with Unlock PDF.
- Large scanned PDFs are mostly images. Compress PDF shrinks them the most.
- Your original file is never modified; you always download a new copy.
Adjust PDF Colors FAQ
- Are my files uploaded?
- No. This tool runs entirely in your browser tab. Files are read from your disk into memory and the result is generated locally.
- Is it free? Are there limits or watermarks?
- Free and open source (MIT). There are no file-size caps, daily quotas, accounts or watermarks.
- Does it work offline?
- Yes, once the page (and any engine it needs) has loaded, it keeps working without a connection thanks to the service worker cache.
Related tools
- PDF to Grayscale: Convert color PDFs to grayscale or high-contrast black & white.
- Rasterize PDF: Turn every page into an image-only PDF at the resolution you choose.
- Merge PDF: Combine multiple PDFs into one ordered document with drag-and-drop sorting.
- Split PDF: Split by ranges, every N pages, or extract each page into a ZIP.