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Free and open source

One photograph across every monitor

The picture carries on over the frames instead of starting again on each screen. Keep it still, pair a light one with a dark one, or run a whole day on a schedule, across three displays or one.

Download for macOSView on GitHub

Free and open source under the MIT licence. Requires macOS 15 Sequoia or later on an Apple Silicon Mac.

Photograph by Ganapathy Kumar on Unsplash, one of the photographs the app ships with.

Three kinds

One image, a pair, or a whole day

Every wallpaper SpreadPaper makes is one photograph laid across the displays you actually have, whether that is three of them or one. What changes between the three kinds is how many photographs you hand it, and what decides when they change.

Two of the three ask for no second display at all. A Light and Dark pair and a day on a schedule are worth having on a single screen, and a laptop on its own is a perfectly ordinary way to run this.

Photograph by Ganapathy Kumar on Unsplash.

Static, one image

One photograph, every display

Drag a wide photograph into place on a canvas that mirrors your real display arrangement, and it goes up as one continuous picture. It stays there until you change it.

The laptop sits lower than the monitor, so it shows the lower part of the picture, which is what macOS does with a real arrangement. Light half by Ganapathy Kumar, dark half by Michaela, both on Unsplash.
  • LightThe beach
  • DarkThe palms

Light & Dark, two images

A pair that follows the appearance

Hand SpreadPaper two photographs, one for light appearance and one for dark. Switch your Mac yourself and the wallpaper follows on every display at once. Set Appearance to Auto and macOS makes the switch on the same schedule Night Shift runs on.

Photographs by Simon Lohmann, Antony Sklivagkos, Michał Parzuchowski and Benjamin Voros on Unsplash.
  1. 06:00Sunrise
  2. 12:00Midday
  3. 18:00Evening light
  4. 23:00The Milky Way

Dynamic, up to 16 images

A whole day on a schedule

Up to 16 photographs, each with a start time you set on the clock. SpreadPaper writes them into a HEIC dynamic desktop carrying the time metadata macOS reads, so every screen turns over at the same moment.

The editor

Place the wallpaper exactly where your monitors sit

The canvas is your display arrangement, the one macOS already knows about: the same sizes, the same order, the same gaps. Drop a photograph on it and drag, and it snaps to the middle and to the edges as it passes them, so what you line up here is what lands on the glass.

An ultrawide with a display stood on its end beside it, laid out the way the Mac reports them, and the editor's own controls floating over the bottom of the canvas. The hairline rectangle is what the render keeps, and the photograph reaching past it is cropped away.

Zoom, fit and flip

A small set of controls floats over the bottom of the canvas: zoom between 10 and 300 per cent, fit the image to the canvas in one click, and mirror it horizontally when the composition reads better the other way round.

One file for every screen

Each display gets its own rendered file, keyed on the display ID rather than the name, so two identical monitors never end up sharing one picture. Wallpapers go up one at a time, so a second click cannot overtake the first.

Look before you save

Preview puts the wallpaper on your screens with the editor still open, so you can judge it where it will live. Save keeps it as a preset, and Save & Apply does both at once.

Bezel compensation

Monitors have frames, and on a spread wallpaper those frames sit right in the middle of the picture. SpreadPaper pushes the display frames apart by the width of the housing between them, so the photograph carries on behind each frame rather than being drawn on both screens at once. A ridgeline then runs straight across the gap.

That is a trade you are making on purpose: the strip behind each frame is part of the image you never see. Set one width for all your displays or a pair for each of them, horizontal for the left and right edges, vertical for the top and bottom, measured in points. The controls appear once a second display is connected, and Settings holds the gap new displays start from.

Matched displays with about an inch of housing between each pair of screens. The frames are drawn as glass, so you can see the picture carrying on behind them, with a blank line down the middle of each gap where the air between two monitors is. What the glass covers is the part of the picture the render hides on purpose, and the ridgeline meets at the same height on the far side of it. Whatever width the housing is, the output is correct for the monitors it describes.

Download

Download SpreadPaper, free and open source

SpreadPaper is a native macOS app released under the MIT licence. Every version ships from GitHub as a DMG and a ZIP, with no account to make and nothing to pay for.

Download the latest releaseView the source

What it needs

macOS
15.0 Sequoia or later
Mac
Apple Silicon
Displays
One is enough for a Light and Dark pair or a day on a schedule. Two or more to carry one photograph across them
Download
DMG or ZIP, from the GitHub releases page
Licence
MIT, free and open source

On an Intel Mac or an older macOS? Open a feature request and say so.

macOS blocks the first launch

Take either route below. It takes a minute, and only the first time.

Through System Settings

  1. Drag SpreadPaper to your Applications folder.
  2. Open it, then click Done on the warning.
  3. Open System Settings, then Privacy and Security, and scroll to the bottom.
  4. Click Open Anyway, then confirm with Open.

Or in Terminal, before you open it

Drag SpreadPaper to your Applications folder, then run this. It skips the warning entirely.

xattr -dr com.apple.quarantine /Applications/SpreadPaper.app

Gatekeeper, the macOS check that vets apps before they run, asks for a confirmation when an app carries no Apple Developer ID signature.