How to Extract Text from Images and Screenshots

Need to copy text from a screenshot, scan a document, or digitize a printed page? OCR technology makes it instant — and with Presend, it happens entirely in your browser.

What is OCR?

OCR (Optical Character Recognition) is the technology that converts images of text into machine-readable text. It's what lets you:

• Copy text from a screenshot of a website that blocks selection
• Search through scanned PDFs
• Digitize printed documents without retyping
• Extract data from photos of receipts, forms, or signs
• Translate text in images by first extracting it

The privacy risk of cloud OCR

Most OCR services — Google Vision, Azure Computer Vision, Amazon Textract — require uploading your image to their cloud. This is problematic for:

• Medical records — Patient data protected by HIPAA/GDPR
• Legal documents — Attorney-client privilege, NDAs
• Financial statements — Bank details, tax documents
• Proprietary information — Internal memos, source code screenshots
• Personal correspondence — Private messages, emails

Even services that claim to delete files immediately still process them on their infrastructure, creating audit trails and potential exposure.

How Tesseract.js works

Tesseract.js is a pure JavaScript port of Google's Tesseract OCR engine, compiled to WebAssembly. It runs entirely in your browser:

1. The language model (traineddata) downloads once per language (~4MB for English)
2. The image is processed locally using your CPU or GPU
3. The recognized text is returned directly to the webpage
4. Nothing is transmitted to any external server

Tesseract is the same engine that powers Google Books, Google Translate's camera feature, and countless document scanning apps. It supports 100+ languages including scripts like Arabic, Chinese, Japanese, Devanagari, and Cyrillic.

Supported input methods

• Drag and drop — Drop any image onto the tool
• File picker — Click to browse and select an image
• Paste from clipboard — Press Ctrl+V (or Cmd+V) anywhere on the page to paste a screenshot directly

Accuracy tips

• Resolution matters — Higher resolution images produce better results. 300 DPI is ideal for scanned documents.
• Contrast is key — Dark text on light backgrounds works best. Inverted colors or low contrast reduce accuracy.
• Minimize skew — Straight, non-rotated text is easiest to recognize
• Clean images — Remove noise, creases, and shadows when possible
• Correct language — Select the right language from the dropdown. Mixed-language text works but may have lower accuracy

Use cases

• Students — Copy text from textbook photos or lecture slides
• Developers — Extract code from screenshots or error messages
• Journalists — Quote text from images of documents
• Researchers — Digitize printed papers and articles
• Administrators — Convert scanned forms to editable text
• Travelers — Read signs, menus, and documents in foreign languages

Step-by-step guide

1. Open the tool — Go to Screenshot to Text
2. Select language — Choose the language of the text in your image
3. Upload or paste — Drag an image, click to select, or press Ctrl+V to paste from clipboard
4. Wait for recognition — Processing takes a few seconds depending on image size
5. Review and edit — Check the extracted text for any errors
6. Copy or download — Save as a .txt file or copy to clipboard

Limitations

• Handwriting — Tesseract works best on printed text. Cursive or messy handwriting has lower accuracy.
• Complex layouts — Multi-column text, tables, and forms may need manual reformatting.
• Decorative fonts — Stylized or artistic text may not be recognized.
• Very small text — Text under 10px may be missed.