# PDF OCR Text Layer Add searchable/copyable OCR text layer to scanned PDF using Tesseract > Canonical page: https://elysiatools.com/en/tools/pdf-ocr-text-layer - **Category:** PDF Tools - **Keywords:** pdf, ocr, tesseract, searchable, copyable, scan ## Overview Run OCR on scanned PDFs and output a searchable PDF with text layer. **How it works:** - Rasterize each PDF page to image (pdftoppm or Ghostscript) - Run Tesseract per page to generate searchable page PDFs - Merge all OCR pages into one searchable PDF ## Inputs - **Source PDF File** (file): Upload scanned PDF - **OCR Languages** (text): eng or eng+chi_sim - **Input DPI** (number) - **OCR Engine Mode** (number) - **Page Segmentation Mode** (number) ## When to use - When you need to search for specific keywords within a scanned document or image-based PDF. - When you want to copy and paste text from a document that was originally saved as a flat image. - When you need to archive physical paperwork digitally while maintaining the ability to index and retrieve information. ## How it works - The tool rasterizes each page of your uploaded PDF into high-resolution images. - Tesseract OCR analyzes the images to identify characters and text layout based on your selected language. - The tool generates a new PDF file, overlaying the recognized text onto the original image to ensure the document remains searchable. - All processed pages are merged into a single, cohesive PDF document ready for download. ## Use cases - Digitizing historical archives or paper records for keyword-based indexing. - Extracting data from scanned invoices or receipts for easier record-keeping. - Converting non-selectable academic papers or reports into accessible, searchable documents. ## Frequently asked questions ### What file formats are supported? This tool specifically supports PDF files. ### Can I process documents in languages other than English? Yes, you can specify language codes like 'eng' or 'eng+chi_sim' in the OCR Languages field. ### What is the recommended DPI for best results? A DPI of 300 is generally recommended for high-accuracy OCR results. ### Does this tool change the visual appearance of my PDF? No, the tool adds a transparent text layer over your original document, so the visual layout remains unchanged. ### Is there a limit to the file size? The tool supports files up to 500MB. ## Related tools - [PDF Denoise](https://elysiatools.com/en/tools/pdf-denoise): Remove visual noise from scanned PDF pages — salt-and-pepper speckle, random grain, and faint background haze — using real image-processing algorithms. Text pages are preserved as searchable vector content. - [Scanned PDF OCR to Word](https://elysiatools.com/en/tools/scanned-pdf-ocr-to-word): Rasterize scanned PDF pages, recognize text with Tesseract, and export an editable DOCX. - [PDF Add Signature Online](https://elysiatools.com/en/tools/pdf-add-signature-online): Add a visible typed or image signature block to selected PDF pages and download the signed copy - [PDF Batch Watermark](https://elysiatools.com/en/tools/pdf-batch-watermark): Apply text watermarks to multiple PDF files with rotation, opacity, and tiling options - [OCR PDF to Structured JSON Bridge](https://elysiatools.com/en/tools/ocr-pdf-to-structured-json-bridge): Extract the PDF text layer with geometry (lines by y-position, tables by column gaps, headings by font size, colon key-value pairs), then fill a user-supplied JSON Schema field by field — labels matched by normalized keys, values coerced to declared types and validated with ajv. - [PDF Deskew](https://elysiatools.com/en/tools/pdf-deskew): Automatically detect and correct skewed (tilted) PDF pages. Preserves text pages as searchable vector content and only rasterizes image pages (e.g. scans). - [PDF Header/Footer Noise Remover](https://elysiatools.com/en/tools/pdf-header-footer-noise-remover): Compare extraction with and without repeated page furniture to spot header/footer noise before using PDF text in RAG, summarization, or editing workflows - [HTML Mail to PDF](https://elysiatools.com/en/tools/libreoffice-html-mail-to-pdf): Render email HTML content to PDF with preserved basic formatting using Puppeteer ## Samples - [PDF Samples](https://elysiatools.com/en/samples/pdf-samples): Generated PDF samples from tools dated 2026-02-01 to 2026-02-10 - [Markdown Slide Deck Samples](https://elysiatools.com/en/samples/md-slide-deck-to-pdf): Remark/Marp style Markdown slide decks for testing PDF export layouts - [Chinese-English Mixed Text Samples](https://elysiatools.com/en/samples/text-chinese-english-mixed-samples): Sample text files with mixed Chinese and English content for testing automatic spacing tools - [Text Case Format Samples](https://elysiatools.com/en/samples/text-case-formats): Examples of different text case formats: camelCase, snake_case, kebab-case, PascalCase, and more ## Related content - [PDF Archival, Accessibility, and Trust Review](https://elysiatools.com/en/hubs/pdf-archival-accessibility-trust): Clean scanned pages, add OCR, prepare PDF/A files, inspect accessibility structure, add bookmarks, and verify signatures before archival handoff. - [PDF LLM and RAG Preparation](https://elysiatools.com/en/hubs/pdf-llm-rag-prep): Turn PDFs into clean, safe, citation-ready inputs for LLM summarization, embedding, search, and RAG pipelines. - [Document OCR Extraction](https://elysiatools.com/en/hubs/document-ocr-extraction): Extract OCR text from scans and convert document pages or images into Markdown, JSON, tables, captions, and retrieval-ready chunks with quality checks. - [PDF Conversion, OCR, and Extraction Workflow](https://elysiatools.com/en/hubs/pdf-convert): Turn office files, wiki pages, comments, and images into PDFs, then extract text, images, tables, structure, or OCR layers from existing PDFs.