Convert PDF to Dark Mode

Our converter applies a colour-overlay layer on top of every page in your PDF using pdf-lib. The original content — text, images, signatures, and form fields — is never modified. Only a visual colour overlay is added, transforming the background to your chosen theme colour.

The conversion adds a new visual layer but does not cryptographically modify the signed byte ranges of the PDF. However, strictly speaking, since bytes are added, a signature verifier will detect the change. If you need both a dark theme and a valid signature, convert before signing.

No. Your PDF is processed entirely in memory. It is never written to disk, never stored in any database, and is discarded immediately after the themed PDF is returned to your browser. Your documents remain completely private.

We offer 7 themes: Dark Mode (default), Dark Blue, Sepia, Night Vision, Solarized, Gray Mist, and Midnight Purple. All themes are available for all users.

Guests can convert 2 PDFs per day. Free account holders get 5 per day. Top-up Credits users get 100 per day. Limits are independent from the PDF SignCheck verification tool limits.

You can upload PDF files up to 50 MB. If your file is larger, consider splitting it into sections first.

Yes! After selecting a theme, the converted PDF is rendered using our PDF.js-powered viewer — the same technology used in our signature verifier. You can preview the themed pages at full quality before downloading.

Dark Mode and Night Vision are optimised for minimal eye strain in dark environments. Solarized is great for developers. Sepia is ideal for long-form reading with warm ambient light.