Textbook dark mode for midnight study sessions
A 700-page PDF glowing white at 1 a.m. is a special kind of pain. Convert the book once — every page opens dark in any reader, on any device, for the rest of the semester.
Drag to compare — a real textbook page converted by the engine below, not a mockup. Content: OpenStax College Algebra 2e, CC BY 4.0 — Access for free at openstax.org
Heavy books, bright pages
Textbooks are the worst night-reading PDFs: hundreds of pages of dense white, read in short painful bursts between deadlines. Reader apps don't help much — most can dim the screen, none can darken the document itself, and the OS-level invert tricks turn every figure into a film negative.
The fix that lasts is to convert the file. White backgrounds become a comfortable near-black, black text becomes soft light grey, and the result is a completely normal PDF — it just happens to be dark, everywhere you open it.
Figures, photos and graphs survive
A textbook is more than text: line graphs, diagrams, photos of lab setups, colored callouts. A raw inversion ruins all of it. This converter is gentler by design:
- Soft Dark tone-maps instead of negating — charts and illustrations keep their shapes and relative contrast, just darker and calmer.
- Keep images original (on by default) leaves full-color photos and figures pixel-for-pixel untouched while the page around them goes dark.
- Equations and tables stay vector-sharp — nothing is rasterized, so zooming into a footnote-sized subscript still renders crisply.
Built for doorstopper books
No page limits, no upload queue, no “file too large” errors from a server. The conversion runs locally in your browser, page by page — a 500-page scanned textbook just takes a little longer than a 20-page paper. Search, copy-paste and the OCR layer of scanned books all survive, because the text layer is never touched — only the colors change.
Convert the book below — drop the PDF in, keep the Soft Dark theme, download the dark version:
Take the dark book anywhere
The converted file is an ordinary PDF, so your whole study setup keeps working: annotate it on an iPad, send it to a Kindle or Boox e-reader, keep it in Zotero, print a chapter if you have to. Dark on every device, with nothing to re-enable per app.
Frequently asked questions
Does it work on scanned textbooks?
Yes. Full-page scan images are recolored along with the page, and the invisible OCR text layer is preserved, so search and copy-paste keep working after conversion. Vector-born PDFs (the kind you download from a publisher) convert perfectly as well.
What happens to figures, photos and graphs?
The Soft Dark theme tone-maps the page instead of negating it, so charts and illustrations stay recognizable — dimmed, not inverted. And the Keep images original checkbox (on by default) leaves full-color photos and figures exactly as they were while text and background go dark.
Can it handle a 500-page textbook?
Yes — there are no page limits. Conversion runs entirely on your device, page by page, so a big book simply takes a little longer. Nothing is uploaded to a server, so there is no queue and no file-size cap beyond what your browser can hold in memory.
Will search and copy-paste still work?
Yes. Pages are not rasterized: text remains real vector text, sharp at any zoom, and OCR layers survive the conversion. Highlights, annotations and citation managers work on the dark file exactly as on the original.
Is it really free?
Yes — free, unlimited, and private. The conversion runs entirely in your browser: your textbook never leaves your device, there are no accounts, no watermarks, and no page limits.