Lucerna: Dark Mode PDF Reader
Read at night, photos intact
Only for Mac
Free · In‑App Purchases
Mac
Every dark mode reader turns photographs into negatives. Lucerna finds the pictures on the page and paints them back the right way round. Free for fourteen days.
Lucerna is a PDF reader for reading at night. The page goes dark — white paper becomes black, black text becomes white — and the photographs stay themselves.
That last part is the whole point. Every reader can invert a page. Turn dark mode on elsewhere and the diagrams survive, but every photograph comes back as a negative: faces in X-ray, skies in orange, plates of food no one would eat. Lucerna reads the page's content stream, finds where the images actually sit, and leaves them alone. Text and line art flip; pictures are painted back the right way round.
TWO READING MODES, NO DIALS
Black & White drains the colour from everything left — the quietest a page can be. Colour on Dark keeps it. Both darken the page, both keep photographs honest. One switch moves between them.
TEXT THAT FITS THE SCREEN
Reflow pours the document's text into a single resizable column, which is how a paper-sized page becomes readable on a phone. Size, line spacing and typeface are yours; pinch the text to size it the way you would size a photograph. On the Mac it is a switch in the toolbar.
A FOLDER IS A LIBRARY
Point Lucerna at a folder and it finds every PDF underneath it, subfolders included, each drawn as its own first page. A subfolder is headed by a preview of itself — the first pages of the documents in it, fanned out like a small stack of paper — so it can be recognised without being opened. Sort by name, date or size. Pin the book you are working through to the top of the recents list so it does not sink out of sight behind something you opened yesterday.
IT REMEMBERS WHERE YOU WERE
Rotation, zoom, layout and your exact place — page and scroll position — are kept per document and given back when you open it again. The position is written as you read, so a force quit costs you nothing. Launch Lucerna and the folder you were browsing and the book you were reading are both there.
BUILT FOR LONG READING
Page thumbnails along the side, drawn exactly as the page you are reading is drawn. Any page can be stuck to the head of the strip and stay there — a title page, a contents page, a plate worth returning to. A chapter drawer that slides in over the page. Live search that highlights as you type. Bookmarks for whole pages and marks for passages, both kept per document. One page, two, two with the title standing on its own, or three across.
HANDS FREE
Auto scroll creeps the reflowed column upwards on its own, from a line every four seconds to a line every fifteen, for the hour when one hand is holding the phone and the other is holding a cup. On a phone or iPad with a TrueDepth camera it can be steered by where you look: near the top of the page and it goes back, near the bottom and it goes on, the middle and it holds still. Close your eyes and it stops. ARKit hands the app the geometry of a face and never the picture.
TURN THE SCREEN, NOT JUST THE PAGES
The whole reader rotates to four absolute angles — for a phone propped on its side against a lamp, flat on a desk and read from across it, or lying down with whoever is reading.
ON EVERY SCREEN YOU OWN
Mac, iPhone and iPad on one purchase. An iPad with the room for it gets the Mac's arrangement — library in a sidebar, thumbnails down one side, bookmarks down the other — and the phone's layout when it is narrowed into Split View.
YOUR FILES ARE NEVER TOUCHED
Inversion is a drawing pass, not an edit: nothing is written back to your PDF. There is no account, no server and nothing collected. The app opens a file and darkens it.
FREE FOR FOURTEEN DAYS
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The developer, Alexander Fitterling, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Not Collected
The developer does not collect any data from this app.
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- Alexander Fitterling
- Size
- 1.8 MB
- Category
- Productivity
- Compatibility
Requires macOS 15.0 or later.
- Mac
Requires macOS 15.0 or later.
- Mac
- Languages
- English
- Age Rating
4+
- 4+
- In-App Purchases
Yes
- Lucerna Lifetime Unlock $29.00
- Copyright
- © 2026 Alex Fitterling