How to Make a Dark-Mode PDF for Night Reading (Without Killing Selectable Text)

Inverting a PDF to “night mode” in a cheap viewer often does two damaging things: it turns pages into images (search dies) and it uses pure white on pure black, which blooms. techyworks dark mode keeps the original text layer and sits a blend overlay on top — the same idea Chrome can display — so copy, find, and form fields still work. The default Comfort theme aims for roughly 12:1–15:1 contrast on charcoal #121212, not 21:1 laser text.

You pick Comfort, Warm night, or High contrast, preview page one, then download *-dark.pdf. Files up to 100 MB are accepted. If page-one corners already look dark, we warn you: running dark mode twice looks muddy.

Upload vs browser fallback

Unlike merge or compress, this conversion may upload briefly so a Python sidecar (PyMuPDF) can apply print-stable blend annotations. The temp file is deleted after download. If upload is blocked, the same overlay approach can finish in the browser. That is the honest split: night-reading quality is worth a short server pass; we still do not keep the PDF.

Step-by-step

1. Open Dark Mode PDF.
2. Drop the file, choose a theme, check the first-page preview (especially photos — they remap too).
3. Download and open it in a reader that honours blend modes (Chrome’s PDF viewer does; some ancient readers may not).

When not to bother

In a bright office, a normal light PDF is usually easier. Dark mode helps in a dim room or on OLED at night. Scanned pages work (pixels remap; OCR is not required). If you need a smaller file afterwards, compress after dark mode, knowing maximum (raster) compress would flatten the overlay — prefer smart compress if you still want selectable text.

Make a night-reading PDF.