Installing the tools

As of 9 October 2026.

If you have installed Fraktur-Korrektor on Windows or on the Mac, everything you need is already there: text recognition with Tesseract (version 5.5.3) and the models for Fraktur and Antiqua come with it. You only need this page if

• you want to clean up curved or stained scans with ScanTailor – that is a separate program (splitting double pages and straightening crooked pages Fraktur-Korrektor does itself: Preparing the scans), or
• you work on Linux – there Tesseract comes from the package manager –, or
• you start Fraktur-Korrektor from the source code (python server.py); then Tesseract is missing.

Fraktur-Korrektor finds both programs by itself if they are installed in the usual place. When you open a PDF, the window shows what was found; so does the start page while the library is still empty.

Tesseract – only on Linux and when starting from the source code

Windows

1. Download the installer provided by Mannheim University Library: https://github.com/UB-Mannheim/tesseract/wiki (the file is called something like tesseract-ocr-w64-setup-5.5.3.20260724.exe).
2. Double-click it and confirm the questions with Next. Keep the suggested folder (C:\Program Files\Tesseract-OCR).
3. Restart Fraktur-Korrektor.

Mac

1. If you do not have it yet, install the package manager Homebrew (its home page shows the one command to paste into the Terminal app).
2. In Terminal, type: brew install tesseract tesseract-lang
3. Restart Fraktur-Korrektor.

tesseract-lang brings the Antiqua model deu, and the older Fraktur model frk as well; Fraktur-Korrektor still downloads frak2021 in addition (see below).

Linux: sudo apt install tesseract-ocr tesseract-ocr-deu (Debian, Ubuntu, Mint) or sudo dnf install tesseract tesseract-langpack-deu (Fedora), or your distribution's package.

The Fraktur model frak2021 by Mannheim University Library (5 MB) is included in the finished program for Windows and macOS. On Linux and when starting from the source code, Fraktur-Korrektor downloads it by itself the first time you read in a book (this needs an internet connection once) and stores it in ~/.fraktur-korrektor/tessdata. This also applies if an older Fraktur model is already installed (deu_latf, deu_frak, frk, Fraktur) – frak2021 recognises better. Only if the download fails does it use the older one. Which model is currently there is shown in the window when you open a PDF (“Fraktur model: …”).

ScanTailor Advanced

Windows

1. From https://github.com/ScanTailor-Advanced/scantailor-advanced/releases download the newest file whose name ends in x64.zip – currently ScanTailor-Advanced-1.1.1x64.zip of version 1.1.1 (April 2026). The newer versions 1.2.0 and 1.2.1 are for Linux only.
2. Unpack the ZIP file (right-click → Extract All), for example to Documents\ScanTailor. No installation is needed; the program is called scantailor.exe.
3. In Fraktur-Korrektor, open a PDF; the window then says “ScanTailor is not installed” and offers Show me the program … next to it – click it and select this scantailor.exe. Fraktur-Korrektor remembers it.

Mac: This is where it gets awkward – the project itself offers no ready-made ScanTailor for the Mac (as of October 2026 it publishes files for Windows and Linux only).

• The Homebrew route (brew install yb85/homebrew-tap/scantailor-advanced, version 1.0.19) does not download a finished program, it builds one on your machine. On Macs with an Apple chip the Qt library comes ready-made; for Intel Macs there are no ready-made packages of Qt and its 38 parts any more – then everything is built, and that takes hours.
• Recommended: an older but finished program – ScanTailor Advanced 1.0.18 from 2022, built by yb85: Scantailor-Advanced-v1.0.18-20220508-macos12.dmg (29 MB, overview). It worked fine on macOS 26 in a test. Drag ScanTailor (Advanced) from the DMG window into the Applications folder – there Fraktur-Korrektor finds it by itself. Two things to note:
  • It is built for Intel Macs. On Macs with an Apple chip it only runs through Rosetta, which macOS offers to install the first time.
  • It is not signed, so macOS refuses to open it at first. To allow it: double-click the program, dismiss the message, then go to Apple menu → System Settings → Privacy & Security and click Open Anyway under Security, then enter your login password. That button is only there for about an hour after the attempt.

(Older, and also available if needed: ScanTailor Universal 0.2.12 from 2021, https://github.com/trufanov-nok/scantailor-universal/releases/tag/0.2.12.)

For a single book the effort rarely pays off. Double pages and crooked pages – the most common case – Fraktur-Korrektor handles itself (Preparing the scans). If your scans are so poor beyond that that ScanTailor would be needed, Transkribus usually gets you there faster.

Linux: .deb package or AppImage from the page mentioned above (version 1.2.1 of May 2026), or your distribution's package.

If a program is not found

When you open a PDF, the window shows which programs were found (for an image folder, only Tesseract); so does the start page while the library is still empty. Click Show me the program … next to the message and select the program file (tesseract.exe or scantailor.exe, on the Mac the program ScanTailor (Advanced)). You can also do it by hand: the path is stored in the file ~/.fraktur-korrektor/config.json (on Windows: C:\Users\<name>\.fraktur-korrektor\config.json):

{
  "tesseract": "D:\\Programs\\Tesseract\\tesseract.exe",
  "scantailor": "D:\\Programs\\ScanTailor\\scantailor.exe"
}

In the same file, "buecher" sets the folder in which new books are created (otherwise Fraktur-Korrektor in your home folder), and "dic" selects a different dictionary.