Lumadia guide
Lumadia changes how PDFs and images look on your screen — darker, dimmer, warmer or clearer — without ever changing the file. Print, download or share, and the original goes out exactly as it came in.
It remembers what you set, per document. Those settings are your library: settings only, never the documents themselves. In Chrome your appearance follows you to your other computers through Chrome sync, and Private sync can carry your whole settings library, encrypted, through your own iCloud, in Chrome and on iPhone, iPad and Mac. It reads no page text and keeps no account of its own.
Get started
In Chrome
- Add Lumadia from the Chrome Web Store.
- Open any PDF — from a link, a download or your own disk. It opens in Lumadia's viewer, already in your appearance.
- For images on web pages, right-click an image and choose View with Lumadia. To have a site's images filtered for you, open the Lumadia toolbar button and switch on Filter images on that site.
Files on your disk: PDFs open in Lumadia with no extra step. To filter images in local files too, or to let
Lumadia read a .lumadia.json settings file beside a PDF, turn on Allow access to file
URLs on Lumadia's details page in chrome://extensions.
In Safari (Mac, iPhone, iPad)
- Install Lumadia from the App Store and open it once.
- Turn on the extension. On iPhone and iPad: Settings › Apps › Safari › Extensions › Lumadia. On a Mac: Safari › Settings › Extensions, then select Lumadia.
- Open a PDF in Safari. If the Lumadia button in Safari's toolbar shows a warning badge, tap or click it and allow Lumadia on that website. You choose the websites; Safari remembers each one.
- Tap the Lumadia button and choose Open in Lumadia. Switch on Open PDFs in Lumadia to skip that step from then on.
Safari can't open local files in Lumadia: open PDFs from websites. A link that goes to a page of a PDF, such as
one ending in #page=3, opens at that page.
The first time Lumadia needs a site, it asks. It asks for nothing it doesn't use, and you can take access back at any time in your browser's extension settings.
Adjust the view
Press the Lumadia button in the viewer's toolbar to open View settings. The eye beside it turns Lumadia on and off: filled means on. Changes show at once. There are two kinds of setting, and they never mix:
- Yours — how you like to read. They follow you to every document, and are applied straight away. They are the Look tab, which says it applies to everything you open, and Colour vision in the Image tab.
- The document's — fixes for this file, such as a faint scan. They wait until you press Save, and they stay with this document only. They are the Adjust tab and the rest of the Image tab, which say so.
| Setting | What it does | Whose |
|---|---|---|
| Appearance: Light, Dark, Match | Dark turns white pages dark. Match follows your device's light or dark mode. | Yours |
| Inverted style: Plain, Smart | Smart keeps photos and colours natural when pages are darkened; Plain inverts everything. | Yours |
| Dim photos in dark | Tones down pictures that aren't inverted, so they don't glare in the dark. | Yours |
| Warmth | Shifts toward amber for evening reading. | Yours |
| Colour vision | Corrects colours for red-, green- or blue-weak vision. | Yours |
| Contrast, Brightness, Levels | Lifts faint text and cleans grey scans. Levels sets the black and white points. | The document's |
| Grayscale, Saturation | Removes or tames colour. | The document's |
| Never invert this document | For pages that look wrong dark, such as a photo with text over it. | The document's |
Apply to lets a fix cover the Whole document or just the page you're on (in a PDF it reads, for example, Page 3).
Handy controls
- Hold to see original (the before-and-after button) — press and hold to see the file as it is; let go to come back.
- The eye in the toolbar, or the On switch at the top of View settings — turns Lumadia off everywhere until you turn it back on. Nothing you set is lost.
- Move panel — beside an image, the panel can sit on either side; drag its header, or use the arrow keys, and Home puts it back.
- Make default — makes this document's fixes the starting point for every document you haven't adjusted. Documents you have adjusted keep their own. Clear default goes back to Lumadia's own starting point. Neither touches your appearance.
- Reset document (or Reset page 3) — removes this document's own fixes, so it opens with your default again. Your default and your appearance stay.
If you see Some settings were made for an earlier version of this file, the file has changed since you saved. Press Apply anyway to keep them, or leave them off.
PDFs and images
PDFs. The viewer has what you'd expect: page box, zoom (Fit width, Fit page, Actual size), Find, a Sidebar with thumbnails and the outline, Page view layouts, rotate and presentation mode. Fillable forms work too; if you try to leave with entries not downloaded, Lumadia asks first. More holds Download and Original viewer, which hands the file back to the browser's own viewer.
| Key | Does |
|---|---|
| N or J / P or K | Next / previous page |
| R / Shift+R | Rotate clockwise / anticlockwise |
| F4 | Sidebar |
| Ctrl+Alt+P | Presentation mode |
| V | Open View settings |
| Shift+V | Turn Lumadia off and on |
| O (hold) | See the original while held |
Images on web pages. Right-click any image and choose View with Lumadia to adjust it there. To have every image on a site filtered, switch on Filter images on the site from the toolbar button. Show a Lumadia button on images on the site puts a small button on each image, to adjust that one image. An image opened in its own tab gets the image viewer, with Fit, Actual size and Original image.
An image keeps one set of settings wherever you meet it — on the page, in its own tab, or on another site.
On a phone. View settings opens as a sheet from the bottom, and your image moves up so it stays in sight above it. Swipe the sheet down or tap Done to close it. Turn the phone sideways and the sheet moves to the side.
Where your settings live
Lumadia keeps your settings in up to three places. Your documents are never stored anywhere by Lumadia: only your settings for them. Open the Library page to see the places and to choose: in Chrome from Library and sync… on the Lumadia toolbar button, and in the viewer from More › Library.
| Place | What it holds | When |
|---|---|---|
| On this device | Your appearance, your default, each document's own settings and your per-site switches | Always. There is nothing to set up. |
| Same appearance in every Chrome | Your appearance and your default, nothing else | Chrome only. On unless you switch it off. It uses your own Chrome sync. |
| Private sync with iCloud | Your whole settings library, encrypted on this device first. Never your documents. | Only if you turn it on. It uses your own iCloud. |
Documents you have adjusted and the sites you switched on never travel through Chrome sync. Once Private sync is on, it carries your appearance too.
Turn on Private sync
On the Library page, open Private sync with iCloud and choose Walk me through it. The steps are shown along the top, and you can stop at any step and pick up later.
- iCloud. In Chrome, choose Connect iCloud and sign in with your Apple Account in Apple's own window; Lumadia never sees your Apple password. On iPhone, iPad and Mac, choose Check iCloud: Lumadia uses the iCloud your device is already signed in to.
- Recovery. Lumadia shows your recovery key. Write it down and type its last group back to confirm. On iPhone and iPad, Save to Passwords keeps it in Passwords too. Two copies are safer than one.
- Passkey (Chrome only, optional). Add a passkey, so your other computers unlock with Face ID, Touch ID or your device password instead of the recovery key.
- Sync. Lumadia sends your settings to your iCloud, locked with your key. Then you're all set.
On your next device, open Private sync and choose Already use Private sync on another device?. Connect or check the same iCloud, then unlock with your recovery key (in Chrome, a passkey works too). Your settings arrive. Until then nothing is lost: changes wait on the device.
Keys and devices. Each library has a short code, such as Library 7KQ2. Replace recovery key… gives you a new one; the old one stops working. In Chrome, passkeys carry the code in your password manager and keep working.
Back up and restore. Export… saves your whole settings library as one encrypted file, wherever you choose. Import a library file… opens one with its recovery key (in Chrome, a passkey works too), shows what will change, and merges only when you say so. An import never removes anything.
Turn off. Turn off stops Private sync on this device. Your settings stay here, and your other devices keep syncing.
Delete from iCloud. Under Keys and devices, Delete from iCloud… removes your Lumadia settings from your iCloud. Every device keeps its own settings and stops syncing; encrypted exports you saved are not affected. iCloud's own storage settings can't do this for Lumadia, so this is the way.
Lost every way in? Under Private sync, open Start over with a new key and choose Make a new key…. It encrypts your library again from what this device holds, with a new recovery key. Your other devices will then need the new recovery key.
Privacy
Lumadia is designed to protect your privacy. What you read and how you view it stay with you — your library stays on your device, and is encrypted before it ever leaves it, by sync or by export, so only you can read it. The developer collects no data from Lumadia, and has no way to see which documents you open.
| Question | Answer |
|---|---|
| Does Lumadia read my pages? | No. It changes how pixels are drawn. It reads no page text and sends nothing to us. |
| Is there a Lumadia account or server? | No. Settings live on your device. In Chrome your appearance also goes to your own Chrome sync unless you switch that off, and your settings library goes to your own iCloud only if you turn on Private sync. Your documents never go anywhere. |
| What is in iCloud? | Your settings, as encrypted blobs with scrambled names. Never your documents. Without your recovery key (or, in Chrome, your passkey), neither Apple nor we can read them, or tell which files or sites they belong to. |
| What can Apple still see? | How many items there are, their sizes, and when they changed. Never what they are. |
| Are exports safe to email? | Yes. Every export is encrypted; there is no plain export. |
| How do I delete my settings from iCloud? | Delete from iCloud… under Library › Private sync with iCloud › Keys and devices. |
| Does printing or downloading include my settings? | No. The original file goes out unchanged. |
| Why does it ask to access sites? | To find and filter images on pages. In Chrome it asks once, with Allow on all sites; in Safari you choose per site in Safari's settings. You can take it back at any time. |
| Who holds my keys? | You. Your recovery key is yours to keep; on iPhone and iPad it can live in Passwords. In Chrome, a passkey can live in your password manager too. Lose every key and your synced settings can't be recovered — though each device keeps its own copy. |
Lumadia uses only the encryption built into your browser and Apple's systems — no home-made cryptography. The full privacy policy has the details.
Quick answers
| If… | Do this |
|---|---|
| A page looks wrong in dark, e.g. a photo under text | Switch on Never invert this document, or Never invert this page for one page of a PDF. |
| A scan is faint or grey | Raise Contrast, or set Levels; then Save. |
| Colours look odd in dark | Set Inverted style to Smart. |
| I want the plain file back for a moment | Press and hold Hold to see original. |
| Open in Lumadia is greyed out in Safari | Lumadia opens PDFs from websites, not local files or blank tabs. Open the PDF from a website. |
| Lumadia can't filter images on a page | Some pages, such as browser and store pages, are closed to all extensions. |
| Safari shows a note over a PDF | The site wouldn't let Lumadia fetch its own copy, so Lumadia is filtering Safari's view instead. Turn off removes it. |
| A source says Signed out since … | Press Sign in on the Library page. Changes are kept until it's back. |
| A source says Locked | Press Unlock and use your recovery key (in Chrome, a passkey works too). |
| An import says newer version | Update Lumadia on this device, then import again. |
| I want it off for a while | Tap the eye beside Lumadia in the toolbar. Everything you set is kept. |
| I use a dark-mode extension and a PDF turns light again | That extension is inverting the page around Lumadia's viewer. Set it to leave PDFs alone, or use its default mode; keep it for web pages and Lumadia for documents. |
| I want the same look on my other computers | In Chrome, keep Same appearance in every Chrome on, on the Library page. It is on unless you switched it off. |
| I want each document's settings on my other devices too | Turn on Private sync with iCloud on the Library page. |
Still stuck? See Support, or write through the contact form.