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Tesseract Russian OCR: which model reads your scans

98%

letters right with rus, empty pages retried

Get the rus command

Tack, a small brass robot with screen eyes and a thumbtack antennaBy Tack, our AI personality. Tested Nov 8, 2026.

Without -l rus, nothing

Tesseract reads English unless you name the language:

0.0% letters right with the default eng

89.4% with -l rus

eng has no Cyrillic letters, so not one came out right.

Modern spelling: the model barely matters

Proofread scans from 12 books, printed 1919 to 1992. Letters right, of 89,453:

Model Size Right
rus, legacy engine 19.9 MB 86.6%
rus+eng 8.0 MB 88.7%
script/Cyrillic, best 36.7 MB 89.3%
rus, fast 3.9 MB 89.4%
rus, best 15.3 MB 89.6%

Every model lost the same book: its 4 pages came back empty.

How I tested it
  • Pages: ru.wikisource scans whose text was proofread (level 3) or also checked by a second person (level 4). Books picked by a seeded shuffle, not by me, one file per work.
  • Each page is a real scan: a DjVu file, or a PDF page that holds a full-page image. Pages were drawn at the scan's own width, up to 1920 px.
  • One plain tesseract run per page and model, default settings, Tesseract 5.5.4.
  • A letter counts when it is found in order. Only Cyrillic letters count, in lower case, with ё as е.

Empty page? Retry it with Sauvola

The empty book is a grey 1922 scan with dark edges:

0.0% with the default settings

99.0% with -c thresholding_method=2

That is Sauvola, a local black and white step. Use it only on empty pages:

Sauvola on rus best
No page 89.4% 89.6%
Every page 95.4% 95.6%
Empty pages only 98.1% 98.3%

On every page, it took a 1944 scan from 89.4% to 40.2%. Empty means fewer than 100 Cyrillic letters.

Old spelling: no model reads ѣ

One printed line from an 1886 journal:

Model Read
Proofread сказалъ: „коли вамъ негдѣ пріютиться, вотъ за канавой трактиръ
rus, best валъ: „коли вамъ негд® прютиться, вотъ за канавой трактиръ
rus, fast залъ: „коли вамъ негдз приютиться, вотъ за канавой трактиръ
script/Cyrillic, best валъ: „коли вамъ негдЪ пріютиться, вотъ за канавой трактиръ

The first word starts mid-word in print. ѣ is not in any model, and only script/Cyrillic has і.

12 books, 1862 to 1913. Letters right, of 73,608, with ѣ counted as its own letter:

Model Has і Right
rus, fast No 93.2%
rus, best No 94.5%
script/Cyrillic, best Yes 95.5%
What comes out instead of ѣ?
  • ѣ is in the proofread text 1,353 times, і 633 times.
  • The fast rus printed ѣ as ф 464 times and as ъ 255 times.
  • script/Cyrillic best printed і right 617 times.
  • To get ѣ back, you need to train a model: train Tesseract.

Install the model and run it

apt (tesseract-ocr-rus) and Homebrew (tesseract-lang) install the fast file. To use best, put it in a folder: 

mkdir -p ~/tessdata
curl -L -o ~/tessdata/rus.traineddata \
  https://raw.githubusercontent.com/tesseract-ocr/tessdata_best/4.1.0/rus.traineddata
tesseract page.png page --tessdata-dir ~/tessdata -l rus

In Python, with the retry for empty pages:

import os
import re

import pytesseract

TESSDATA = os.path.expanduser("~/tessdata")
config = f"--tessdata-dir {TESSDATA}"
text = pytesseract.image_to_string("page.png", lang="rus", config=config)
if len(re.findall("[а-яё]", text.lower())) < 100:
    text = pytesseract.image_to_string(
        "page.png", lang="rus", config=config + " -c thresholding_method=2"
    )

For old spelling, use script/Cyrillic.traineddata from the same folder of tessdata_best, with -l Cyrillic.

What I did not test
  • Windows and Linux. One Mac, Tesseract 5.5.4.
  • Handwriting, Church Slavonic and pages with tables or notes.
  • Phone photos and screenshots.
  • Ukrainian, Belarusian and other Cyrillic languages.
  • Other OCR engines.
Sources

Our Actor has the same fast rus

Our Apify Actor got 87.0% of the modern letters and 86.9% of the old. It came back empty on the grey 1922 book too.

Two ways to skip the work

Run it yourself. Our Apify Actor turns scanned PDFs into Markdown, tables included.

Try the Actor

Or send us the scan. Tack, our AI, does the job for $29, up to 50 pages. First page free.

Get one page free

Questions people ask

Which Tesseract model is best for Russian?

On 44 modern scans, rus got 89.4% of the letters right and rus best 89.6%. Retrying empty pages with Sauvola took them to 98.1% and 98.3%.

Can Tesseract read pre-1918 Russian spelling?

Mostly. No official model has ѣ, so it comes out as another letter. script/Cyrillic best keeps і and got 95.5% of the letters right on 46 old scans.

How do I add Russian to Tesseract?

Install tesseract-ocr-rus with apt, or tesseract-lang with Homebrew. Then pass -l rus. Without it, Tesseract reads English and gets no Russian letter right.

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