Recognize Russian and English text in scanned PDFs with self-hosted Tesseract and create a searchable PDF result.
Server-side OCR recognizes Russian and English on scanned or mixed pages while preserving existing digital text.Server-side OCR recognizes Russian and English on scanned or mixed pages while preserving existing digital text. The situations below show what this workflow is designed for so you can choose the tool before uploading a document.
The “OCR PDF online” workflow consists of 3 consecutive stages. Review the settings and expected output at each stage because processing creates a new copy instead of overwriting the source.
Select a scanned or mixed PDF.
Choose pages and the recognition language.
Review uncertain words and download a searchable PDF.
The capabilities below describe what is included in the workflow and the resulting file. Use them to confirm whether this tool completes the task or whether another processing stage will be needed.
Limits keep the result predictable by describing supported files, processing boundaries and PDF properties that may require manual review. Read them before starting, especially for complex documents.
The “Make a scan searchable” scenario follows a source file through to a separate result. It shows which action is performed and what should be checked after download.
The file is processed only inside a temporary guest session. Access closes when the session ends, and source and result files follow the service deletion lifecycle.
These answers apply specifically to “OCR PDF online” and extend the main instructions. They cover settings, expected output and the cases that most often need clarification before processing.
Russian, English and mixed Russian-English documents are supported.
Low-confidence words can be reviewed and corrected before rebuilding the searchable PDF.
No. OCR runs through self-hosted Tesseract in the service environment.
Yes. Low-confidence words are marked for manual review.
When processing cannot continue, the service shows a reason code and a safe next step. Resolve the stated issue and upload again or choose another mode; the source document remains unchanged.
OCR_LOW_CONFIDENCESome recognized words are below the configured confidence threshold.
Review the marked words and apply corrections before export.OCR_ADAPTER_UNAVAILABLEThe local Tesseract adapter is temporarily unavailable.
Retry later or continue without OCR when the adapter becomes available.Practical guides provide context that does not fit into a short procedure: how to choose a mode, understand processing consequences and handle the document safely.
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