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DocumentationUsing Substrate

Highlights and notes

Mark passages, attach notes, and keep them privately or in this browser

You can mark passages of a paper in one of seven colours, attach a note to each mark, and keep one longer note for the whole paper. All of it is private. Signed out it lives in this browser; signed in it is stored with your account and follows you to other browsers.

Highlight a passage

1

Select text in the PDF

Drag across the text with the mouse. When you release, a card appears under the selection with a note field, the seven colour swatches and a Highlight button.

2

Add a note, or not

The note field has the focus. Type if you want the mark to carry a note; the button then reads Add note.

3

Save it

Click a swatch to save with that colour, or press ↵ to save with the colour you used last. Esc discards the card. If you typed a note, the side panel switches to My notes.

The swatches are red, orange, yellow, green, blue, indigo and violet, in that order; yellow is the default. The last colour you chose is remembered in this browser and preselected next time. A highlight stores the selected text and the positions of the marked lines relative to the page, so it stays in place at any zoom level.

Change or remove a highlight

Click an existing highlight in the paper. A card shows its note, if it has one, and offers the seven swatches to recolour it in place, Edit note (which opens the highlight in My notes), Copy text, and Remove highlight, which deletes it together with its note.

The My notes tab

The top of the tab is the Private paper note, one free-text field for the whole paper. Below it sit the save status line, the Export notes & highlights button (see Export) and the highlight list, ordered by page and then by position on the page and headed N highlights · private. Tick With notes only to hide highlights without a note. Clicking a card’s text scrolls the paper to its page. Hovering a card reveals a pencil, Add note or Edit note, and a bin, Delete highlight. The note editor opens inline: Save or ⌘↵ keeps the change, Cancel or Esc drops it.

Where your notes are kept

You areNotes and highlights go to
Signed outThis browser's local storage, one entry per paper. The status line reads Saved on this browser.
Signed inYour account, private to you. The status line reads Saved privately, and the same notes appear in any browser you sign in from.

The two stores are not merged. Signed out, the tab says Guest notes stay on this browser. Export a copy before signing in; guest notes are never uploaded automatically. There is no import either, so the export is a copy to keep, not a way to move notes into an account.

The save status line

Every change to the paper note, a highlight or its note is written half a second after you stop typing. If a write fails it is retried three seconds later, and a save is also attempted when you switch to another tab or window.

StatusMeaning
Loading private state…Your notes are being fetched.
Saved privately / Saved on this browserEverything is written to your account, or to this browser.
Unsaved changesYou changed something and the write has not started yet.
Saving…A write is in progress.
Anything elseAn error message. Your changes are still on screen; export them if the error persists.

Closing the tab or navigating away while a change is unsaved triggers the browser’s leave-page prompt. Following a link inside the app asks first: Your notes have not finished saving. Stay on this paper to save or export them. Leave anyway? Links that open in a new tab, and clicks with a modifier key held, are not intercepted.

Conflicts between sessions

Signed in, every save carries the revision it was based on. If the same paper was changed from another browser or tab in the meantime, the save is refused and the status line reads Your notes changed in another session. Export your draft, then reload before editing. From then on this tab stops saving, so nothing overwrites the other session’s work. The same happens when your sign-in has expired.

To recover, press Export notes & highlights to keep a copy of what is on screen, reload the page to load the newer version, and reapply what you need by hand.

Limits per paper

ItemLimit
Paper note100,000 characters
Highlights1,000
Text of one highlight20,000 characters
Note on one highlight10,000 characters
Marked line boxes per page in one highlight1,000
Assistant messages100
Everything together480,000 bytes