Fraktur-KorrektorHomeDeutsch

Usage

Page image on the left, text on the right. The reading line, highlighted in yellow, always stays at the same height; image and text move together. Red marks words the dictionary does not know; orange marks places where an automatic pre-correction made an uncertain replacement. A page number that does not fit the neighbouring pages is red as well (in Fraktur, OCR likes to read “16” as “46”) – the hint names the number that should be there, and Space, Enter correct it like a word. The page number may be at the top in the running head or at the bottom of the page as in more recent books: if a book carries it at the bottom throughout, the program notices this by itself and shows it there in pale grey like the running head. Likewise the running title of more recent books – the book or chapter title with the page number at the top of every page (»Stalins Bauernopfer am Schwarzen Meer 9«) that text recognition read as an ordinary line: it appears in pale grey, is not checked and does not count as text; its number is taken as the page number. You do not need to enter anything, and the files stay as they are; if a page has no number (chapter opening), it follows from the neighbouring pages.

If there are several numbers at the bottom – noise from the page margin below it (»428« / »ı10«) or a chapter number above it –, the one that fits the neighbouring pages counts. With the reading line on the pale page number, the line at the bottom says which page number counts and what was read. You change it like any line with F2: the page number is whatever stands in that line. If the program takes a wrong line for the page number, take the digits out of it with F2.

The program has three states, shown in the top bar: Reading (green), Correction (red) – a red word is being changed – and Edit line (orange).

The reading view: page image on the left, text on the right, the reading line in yellow, unknown words in red

New here? First steps walks you through the essentials using the example book.

Keys

Mode Key Effect
Reading ↓ ↑ (or j k), mouse wheel next / previous line; the text flows across page breaks. Clicking a line makes it the reading line
Reading Space jump to the next red word → correction
Reading double-click a word a red word: correction; otherwise edit the line, with the clicked word selected
Reading double-click in the page image the line under the mouse pointer becomes the reading line, in the image and in the text – handy when you spot a place in the image
Reading F8 (or #) first red word of the reading line is correct → whitelist. F8 again = the next one. With no red word in the reading line: the next one further down the page
Reading Enter if the reading line has a red word: go there; otherwise like F2
Reading F2 edit the reading line freely (punctuation, footnote marks, anything the automatic check misses)
Reading PgDn PgUp, Home End page forward/back, top/bottom of page
Reading G go to page: an input line for the page number appears at the top
Reading S (or /, Ctrl+F, on a Mac also Cmd+F) search the whole book; N (or F3) next, Shift+N previous match (see below)
Reading + − 0 zoom the page image (also Ctrl+mouse wheel over the image)
Reading Ctrl++ Ctrl+− Ctrl+0 (Mac: ⌘) text size for this book (also Ctrl+mouse wheel over the text); remembered. By itself the program chooses it so that a printed line fits into one line on the right as well – Ctrl+0 restores that
Reading Shift+mouse wheel scroll a wide table sideways; it follows the reading line by itself
Reading R reload the page (after changes in another editor)
Correction / Edit line Enter apply and read on (when correcting: if the same line has another red word, that comes first)
Correction / Edit line Ctrl+Shift++ (Mac: ⌘+Shift++) raise the digits before the cursor (or the selected ones) – for footnote marks; again: back to normal (see Footnotes)
Correction / Edit line F7 (or - at the end of the line) insert the hyphenation mark ¬ at the cursor. Within the line - stays a hyphen; if the line already ends with ¬, - puts a hyphen before it (Ost-¬ / Preußen)
Correction / Edit line Shift+Enter split the line at the cursor (see below)
Correction F8 (or #) word is correct → whitelist
Correction ↓ ↑ put a suggested correction into the field (see below); Enter applies it
Correction Tab next red word without changing anything; for a split word, first into its second half
Correction / Edit line Esc or double-click in the text back to reading without changing anything
Reading / Correction F9 batch correction (see below)
Reading U undo the last batch correction (likewise the paragraphs detected on first opening, see below)
Reading F footnotes start at the reading line (see below)
Reading T table: turn separate lines into a table, or dissolve it again (see below)
Reading H heading: level 1 → 2 → 3 → none (see below)
Reading A a paragraph starts here – press A again to take it back (see below)
Reading Shift+A or Shift+Enter double paragraph: a paragraph with a blank line before it, after the end of a chapter, say, or between two stanzas (see below)
Reading I contents: all headings of the book, Enter goes there (see below)
Reading B mark an illustration in the page image so that it goes into the e-book (see below)
Reading L the reading line is a caption – press L again to take it back (see below)
Reading V join the reading line with the next line; Shift+V splits a line joined this way again
Reading Ctrl+⌫ (Mac: ⌘+⌫) delete the reading line, or all lines marked with Shift+↓/↑ – for noise from the scan edge (see below)
Reading Ctrl+Z (Mac: ⌘+Z) bring back the lines deleted last
Reading W show the whitelist
Reading D dictionary: which spelling applies to this book (see below)
Reading Shift+↓ / ↑ select lines, for a note or to delete them (within the page); any other key clears the selection
Reading / Correction F4 or right-click the selection note for Obsidian from the selected passage, otherwise from the reading line (see below)
Reading Z after merging two states of a book: to the next line that was corrected differently on both computers; 1 keeps this version, 2 takes the other (see Saving a book as PDF)
Reading O set the notes folder for this book
anywhere F1 this help

Search (S) and go to page (G)

S – or the familiar Ctrl+F (on a Mac also Cmd+F) – opens an input line in the top bar. Whatever you type there is searched throughout the book – regardless of upper and lower case, ſ counts as s, and a word is found even when it is hyphenated at the end of a line. Enter jumps to the first match after the reading position; it is marked blue in the text and framed in the page image. A small panel stays at the top with the search term, the count (“3 / 17”) and two buttons: N goes to the next match, Shift+N to the previous one, the × closes the search. Esc discards the input.

G asks for a page number in the same way. This means the page of the file (the number in the selector at the top), not the page number printed in the book.

Next to the selector you see which page out of how many you are on ("4 / 30"); the arrows ← and → on either side turn the page like PgUp and PgDn.

Hyphenated words

Words split at the end of a line are written with the mark ¬: Zu¬ / kunft. Both parts are checked together. When correcting, both lines appear as input fields, with the cursor in the first. To reach the second half, press Tab or move past the end of the line with → – back with Shift+Tab or ← at the start of the line (↓ and ↑ do the same as long as there are no suggestions; otherwise they pick a suggestion). Enter applies both lines. F7 inserts the mark, at the end of the line so does - (reachable on a MacBook without fn).

A word split across the page break (Ge¬ at the end of one page, walt at the start of the next, the page number in between) is checked as a whole, too. If it is unknown, both halves are red; the hint then says that the word continues on the other page, and you change each half on its own page.

Suggested corrections

As soon as you open a red word for correction – with Space, with Enter on a line containing a red word, with Tab to the next one, by clicking the word, or because after Enter another red word remains in the same line – the program shows suggestions in a small menu below the word, the most likely first (at most six):

  1. What you have already made of it in this book. Once you have corrected Würllemberg to Württemberg, the next Würllemberg gets that as its first suggestion – the program learns from your correction log, batch corrections included. What you made of it most often comes first.
  2. Typical misreadings of Fraktur OCR, undone: b/d, f/s, n/u, r/t, ll/tt, missing umlaut dots. ber becomes der, Bolk becomes Volk, Zutunft becomes Zukunft – but only if the result is a known word (dictionary, whitelist, or frequent in the book). Words frequent in the book come first.
  3. The dictionary (Hunspell). These take a second or two, so the program works them out for the next red words while you are still reading – when you get there, they are usually ready at once. Otherwise they appear a little later; the first two groups are always there at once. If you have already picked a suggestion by then, it stays – the dictionary suggestions are only appended. This work never slows down your keys: it pauses whenever the program is doing something for you. For words of just two letters the program does not ask the dictionary.

↓ puts the first suggestion into the field, each further ↓ the next, ↑ goes back (down to the word as it was recognised); clicking a suggestion does the same. Enter applies as always. If none of the suggestions fits, just type.

If the program finds nothing for a word, no menu appears. There are no suggestions when editing a line freely (F2) or in a table, nor for a red page number in the header – there the expected number is already in the hint above the field.

Batch correction (F9)

The same misreading often occurs dozens of times in a book (ber for “der”, bie for “die”). Batch correction lists every occurrence of a word at once and replaces them after a quick look at the image snippets.

Each occurrence shows page and line, the image snippet with a red frame, and the text. All occurrences are ticked to begin with; words split across line ends are found as well.

Key Effect
↓ ↑ move through the list
Space tick / untick
A all on / all off
Tab change the replacement
Enter replace all ticked occurrences
Esc cancel

U in reading mode undoes the last batch. Lines you have changed by hand since then are left alone.

Footnotes (F)

In the text file, footnotes follow a line --- and always run to the end of the page. F sets or moves this separator to just before the reading line. If the reading line is the first footnote line, F removes the separator again.

If text recognition did not separate the footnotes – it often reads their superscript numbers as »3!«, »°« or »S,« –, the program detects them itself when the book is first opened: by the larger gap that precedes the footnote rule in print, and by the smaller type. It then sets the separator on those pages and says in the status line at the bottom on how many. Where it got it wrong, correct it with F as above. This happens only in books that really have footnotes, and only on pages that do not have a separator yet.

Footnote marks in the text. The superscript numbers that refer to a footnote are often read by text recognition as *, or stuck to the word as ordinary digits (»beziffert.36«). To enter them raised: type the number and press Ctrl+Shift++ (as in Word; on a Mac ⌘+Shift++) – in the field it then appears raised (»beziffert.³⁶«), in the text file as <sup>36</sup> as in an e-book. The same keys again make it normal. The suggestions make it easier: on pages with footnotes the program marks such places in blue, Space (or Enter in the line) goes there as to a red word, and the number is already in the field, raised – Enter accepts it. If it is wrong, ↑ and ↓ count it up or down, or you type the correct number: at this place it is raised straight away. The number follows from the numbering: the previous footnote and the readable numbers of the footnotes at the bottom of the page. Where text recognition swallowed many marks, it is off – once one is set correctly, the following suggestions go by it. The quotation of a note (F4) contains no footnote marks.

Splitting and joining lines

Sometimes text recognition misses a line break – two lines (or two table cells) end up in one – or it makes one too many.

The program also splits or merges the image area of the line (when splitting, proportionally at the split point; if it is several lines high, horizontally between the printed lines). This way every line of text keeps its place in the page image – unlike changing the number of lines in another editor. Inside a table, the table is renumbered afterwards: shifted columns fall back into place.

Deleting noise from the scan edge

With scans that have a dark edge or a cut-off neighbouring page, text recognition sometimes reads lines that are not text at all – at the top, or below the page number, there are strings like BTB, LLL AAA or E NN SE HE K. Delete such lines in reading mode with Ctrl+⌫ (on a Mac ⌘+⌫, the delete key): the reading line disappears without asking. Several lines at once: mark them with Shift+↓/↑, then Ctrl+⌫.

Deleted by mistake? Ctrl+Z (on a Mac ⌘+Z) puts the lines deleted last back in their place, also several times in a row. The Del key on its own deliberately deletes nothing – it is too easy to hit while reading.

The running head, the footnote rule, the page number at the bottom and lines of a table cannot be deleted this way. As with splitting and joining, the image area of the line goes too, and the other lines keep their place in the page image; every deletion is recorded in the log korrekturen.log.

Tables (T)

Text recognition usually tears tables apart into single lines – a listing turns into

im Jahre 1811
16 842 Eimer,
1812-
12 409

Put the reading line on the first line and press T. Use ↓ to extend the range to the last line of the table and 2 … 9 to choose the number of columns; the preview at the top shows at once how the lines are distributed over rows and columns (in order, from left to right). H turns the first row into column headers, Enter applies, Esc cancels. T on an existing table removes the markup again after asking – the text stays.

The program does not invent a format of its own for this; it writes the same markup into the text that an EPUB uses (XHTML):

<table><tr><td>im Jahre 1811</td>
<td>16 842 Eimer,</td></tr>
<tr><td>1812-</td>
<td>12 409</td></tr></table>

Every line stays a line – one cell per line – so that the alignment with the page image is kept. You never get to see these control characters in the program: on the right the finished table appears as a table, with borders and columns, and the input field, too, shows only the content of the cell. The reading cursor moves cell by cell, and the matching place in the page image is highlighted on the left. The word check skips the markup. You correct the content of the cells like any other text (delete superfluous dashes as in 1812- with F2).

Shifted columns: if two cells are in one line (1812- 12 409) because text recognition missed the line break, all columns from there on shift by one. Split the line at that place (F2, position the cursor, Shift+Enter) – before or after creating the table; an existing table is renumbered by the program afterwards.

Limitation: the cells have to be in reading order (row by row). If text recognition read a table column by column, it cannot be marked up this way.

Headings (H)

H marks the reading line as a heading: level 1 the first time (<h1>…</h1>), the next level with each further press, ordinary text again after level 3. Headings are shown larger and bold, without visible control characters.

If a heading runs over two or more lines (“Chapter Three.” / “The Journey to Odessa.”), select the lines with Shift+↓ (or with the mouse) and press H: they get the same level, and the program joins them into one heading. If the reading line is part of such a heading, H changes the level of all its lines – no new selection needed. A paragraph start in the line is dropped: a heading is a block of its own. Best use the levels the same way throughout the book: chapters level 1, sections within them level 2; if the book has parts, the parts are level 1 and the chapters level 2.

Contents (I) shows all headings of the book, indented by level, with the printed page number – so you can see whether a chapter is missing. ↓ ↑ select, Enter or a click goes there, Esc closes. When you save the book as a PDF, the headings become the PDF's table of contents, which every PDF reader shows in its sidebar. When you save the book as an e-book, they become chapters and a clickable table of contents.

Paragraphs (A)

In print every line runs to the margin; only the indentation of its first line shows where a paragraph begins. For the e-book, where the text flows freely, the program has to know the paragraphs. When a book is opened for the first time, it detects them itself from the indentation in the page image and indents the first line of each paragraph in the text too; the status line at the bottom says how many it found.

Where it got it wrong: A on the reading line sets a paragraph start there, pressing A again removes it. U undoes all detected paragraph starts at once, as long as no batch correction came after them (U says beforehand what it will undo). The book is not detected again after that – then set the paragraphs by hand with A.

Only what looks unambiguous is detected: the line is indented against its neighbours, and the line before ends with a punctuation mark. Verse, lists and indexes are thus mostly left alone. Without line positions in the image (a book from an EPUB without a PDF) or in a book without indentation, the program detects no paragraphs. In the text file a paragraph start is written as <p> at the beginning of the line, as in an EPUB.

Double paragraph (Shift+A or Shift+Enter)

Sometimes the print has a blank line between two paragraphs: where one section ends and a new one begins, at the end of a chapter before the next part, or in a poem between two stanzas. Shift+A – or Shift+Enter – on the first line after it sets such a double paragraph: the text shows a space above it, the e-book a blank line. Shift+A once more takes the blank line away again and the paragraph stays; A takes back the whole paragraph. On a tablet the button is called ¶¶. (In the input field, by contrast, Shift+Enter splits the line, see Splitting and joining lines.)

The blank line is not a line of its own in the text file – every line there belongs to a line in the page image. It is written as <p><br/> at the beginning of the line. When the program reads in an EPUB, a section break in it (<hr/>) becomes a double paragraph too.

Illustrations (B) and captions (L)

Of the page image the program only knows the text lines. You show it where an illustration, a map or a plate is – then it goes into the text as a picture when you save the book as an e-book. The text itself does not change.

Marking an illustration (B): The B key shows the whole page on the left. If the program finds a printed area that contains no text line, it suggests a frame (dashed).

Marked illustrations have a green frame in the page image, while reading too. To get rid of a frame: B, click the frame (if there are several on the page; Tab goes to the next) and Del. A page can have several illustrations; press B once for each.

The suggestion is only a suggestion: a line that text recognition overlooked, or a library stamp, looks just like a small illustration to the program. If lines of gibberish lie over an illustration (text recognition took the picture for text), delete them with Ctrl+⌫, see Deleting noise from the scan edge.

Caption (L): If there is a caption below the illustration ("Fig. 3: The colony of Rohrbach"), text recognition read it as an ordinary line – in the e-book it would sit in the middle of the paragraph. L marks the reading line as a caption; it then appears smaller, with a green bar at the edge. If the caption runs over several lines, give each line an L. L again takes it back.

In the e-book the caption stands below the nearest illustration on its page and also serves as its description for screen readers. An illustration without a caption stands where it belongs according to the position of the lines in the page image – but never in the middle of a paragraph: it follows the paragraph it lies in.

In the text file a caption is written as <figcaption>…</figcaption>, as in an EPUB. The frames of the illustrations are kept in the file bilder.json in the book folder; they travel to another computer with the saved PDF. If a page is replaced, its frames are dropped – the new image is a different one.

Bold, italics and underline (Ctrl+B, Ctrl+I, Ctrl+U)

As in Word: select the words with the mouse – or whole lines with Shift+↓/↑ – and press Ctrl+B for bold, Ctrl+I for italics or Ctrl+U for underline (⌘ on a Mac). The words appear in that type style right away, and later in the e-book too. The same selection once more takes it back. The selection may run over several lines. Type styles taken in from an EPUB can be changed in the same way.

The three keys also work in the input field (F2 or while correcting): there they put the characters <b>…</b>, <i>…</i> or <u>…</u> around the selected characters – without a selection around the word at the cursor.

Further markup

If you like, you can also enter further markup by hand with F2; the program knows <em>, <strong>, <i>, <b>, <u>, <sup>, <sub>, <p>, <blockquote> and <br/>, does not treat them as words, and shows font markup (italic, bold, underline, superscript, subscript) as such.

Whitelist (W)

The whitelist holds the words you confirmed with F8 (names, places, old spellings). W shows it, newest first, with a filter. Del, Space or a click removes a word or restores it – it then turns red again in the book.

Dictionary (D)

Whatever the dictionary does not know turns red – so the dictionary has to suit the book. D (or “Dictionary” in the top bar) shows three tick boxes; the choice applies to this book only and is saved:

Tick box Examples What for
Accept spellings from before 1901 Thür, Noth, seyn, giebt, civilisiren 19th-century prints – and newer works that quote old sources verbatim
German spelling 1901 to 1996 daß, Schiffahrt, rauh most Fraktur prints, everything up to the spelling reform
Reformed spelling (from 1996) dass, Schifffahrt, rau newer books, scripts, papers

When a book is read in, the program estimates the year of publication from the title pages and imprint and ticks the boxes accordingly: before 1902 the first two, up to 1997 the middle one, from 1998 the lower two (the changeover took years, and newer works quote older texts). After every change the window shows how many red words the book had before and has now – so you see at once what fits. On the keyboard, 1, 2, 3 toggle the boxes and Esc closes. Genuine misreadings (ber, bie, Bolk) stay red in every setting.

Independently of this, the following always count as correct: common abbreviations (Vgl, Bd, Ebd, Hg, Bible references such as Offb, Joh), sigla in capitals that occur more than once (BWKG, LKA), and longer words that occur at least three times in the book (mostly names). A name that is still red is confirmed once with F8 – this then applies to every occurrence.

Notes for Obsidian (F4)

If you take excerpts while reading, every passage can become a note in Obsidian – modelled on Niklas Luhmann's Zettelkasten: one thought per note, each with its source.

  1. Once per book: press O (or “Notes” in the top bar) and enter the folder in your Obsidian vault where the notes on this book belong, e.g. …/Vault/Research/Leibbrandt 1928. The “Choose folder …” button opens the file dialog; a missing last folder is created. The choice is stored in buch.json.
  2. While reading, select a passage with the mouse – across several lines if you like – and press F4, or right-click the selection. Without a mouse: go to the first line, hold Shift and select the lines you want with ↓ or ↑ (highlighted in blue), then press F4. Without a selection the reading line becomes the note. If no notes folder has been set yet, F4 asks for it first.

The program creates a file in that folder, numbered consecutively, for example 07 Page 57.md:

**Note**



---

> Die Kolonisten zogen nach Rußland und der Weg war weit.

Page 57, Line 3–4, [[0 Source|Leibbrandt 1928]] · [Scan](http://localhost:8765/stelle?buch=6b8d…&seite=057&zeile=3-4)

At the top room for your own remark, below the rule the quotation (words hyphenated at line ends are joined) and the page – the printed page number from the running head or the foot of the page; if it is missing or does not fit the neighbouring pages, the number the neighbouring pages imply; otherwise the PDF page –, the lines (counted as in “Line 3/42” in the program's top bar), a link to the book's source note and the link back to the scan (see below). The program creates that file, 0 Source.md, as a template with the first note; enter there where the book comes from (university library, interlibrary loan …) and the citation as Zotero gives it. This way every note is one click away from its full source. The quotation is also placed on the clipboard.

If Obsidian is installed, it opens the new note immediately and, on Windows, comes to the front (the folder has to be inside a vault Obsidian knows). Without Obsidian the file simply stays in the folder – it is plain Markdown.

Back to the source: Clicking Scan at the end of the source line opens the book in Fraktur-Korrektor right at that passage – the page image on the left, the text on the right, the quoted lines highlighted in blue and framed in blue in the image. So while writing you can check without searching whether the quotation is right, what comes before and after, and what the footnote says. Your bookmark stays where it was; it only moves on when you read on in the book yourself.

Highlights you made on your Kindle become notes in the same way: Highlights from the Kindle. How to write notes on a tablet or phone is described below under Reading on a tablet.

Replacing a page

One page was scanned crooked, cut off or blurred, and the book is otherwise fine? Then the whole book need not be recognised again. Photograph or scan the page once more and click Replace page … in the top bar (only on the computer the program runs on):

  1. Choose the file – an image (JPG, PNG, TIF) or a PDF. For a PDF with several pages, say which page is meant; the number of the page you are on is suggested.
  2. Choose the script (Fraktur or Antiqua) and click Replace page.

The page image is swapped and the text of this page only is recognised again – with Tesseract, or without Tesseract with the text a searchable PDF already carries. All other pages stay as they are, including your corrections there. The previous version of the page – text, line positions and image – is backed up in the book folder (vorher-<date>.zip); Earlier version in the library brings it back.

Reading on a tablet

From a tablet – say the iPad on the sofa – or from a second computer you read along over your home network. For this, the program must be started on the computer with the option --lan; the address for the tablet is shown in the window at start-up, for example http://192.168.1.20:8765. Type it into Safari and bookmark it. There is no password protection – use it on your own home network only. Books can only be added on the computer the program runs on.

It works on the iPhone too, best held upright: then the text stands alone, and everything below applies just the same. Because the screen is narrower, the header leaves out the word “Page” and the page count “1 / 300” (the selection shows the page); Library is in the ☰ menu.

On the tablet you work with your finger:

Notes on a tablet or phone

Notes with your remark can be made on the go too – without needing another app:

  1. Select a passage with your finger: press and hold a word, then drag the handles.
  2. Tap Note from selection at the bottom (without a selection the button says Note and takes the reading line).
  3. A field opens: the quotation at the top, below it you write your remark. Save note – done.

The note is created on the computer, in the notes folder you set there for the book (O) – just as with F4: numbered consecutively, with the quotation, page and line, the reference to the source note and your remark at the top. Obsidian on the computer shows it right away; with Obsidian Sync it is on your other devices too. The remark may stay empty; you can add to it later in Obsidian. Click the Scan link in the note on the computer: it leads to the program running there.

No notes folder set yet? The note is still not lost: it waits in the book folder. As soon as you set a notes folder on the computer with O, it moves there by itself and gets the next free number. You can also set the folder on the computer via Remote Desktop – the program recognises the computer even when the browser there shows the home-network address from the tablet.

With a keyboard, Ctrl+Enter saves and Esc cancels. This also works on a second computer reading along over the home network.

Our recommendation: create the note via the computer – as described above, writing the remark in the program. Obsidian on the tablet itself does not work reliably with the program (as of October 2026): if Obsidian is not already open in the background on the iPad, it shows only the note you had open last instead of the new one, and the note is not created at all. This is a bug in Obsidian that the program cannot fix. Via the computer nothing is lost; with Obsidian Sync the note is on the tablet shortly afterwards, and you can carry on writing there.

Still want Obsidian on the tablet? If Obsidian is installed there and keeps the vault in step with the computer (Obsidian Sync), you can tick Open Obsidian on this device instead under ☰ → Notes. Then Note opens the new note with quotation and source in Obsidian, and you write your remark there; the first time, Safari asks whether it may open Obsidian (if it does not open by itself, tap open in Obsidian in the message at the bottom). If the vault has a different name on the tablet than on the computer, enter that name there. If Obsidian shows only the note you had open last, go back to the program and tap open in Obsidian in the message once more – the second time the note is usually created.