How do I turn multi-page PDFs into searchable text with OCR?

To turn multi-page PDFs into searchable text with OCR, you generally need to:

1. Extract each page as an image if the PDF is scanned or image-based.
2. Run OCR on those images to detect text.
3. Save the result as searchable text or a new PDF with an invisible text layer.

Easiest options

1) Adobe Acrobat

• Open the PDF
• Go to Tools → Scan & OCR
• Choose Recognize Text → In This File
• Save the PDF

This creates a searchable PDF.

2) Free command-line tool: ocrmypdf

This is one of the best options for multi-page PDFs.

Install

• macOS: brew install ocrmypdf
• Ubuntu/Debian: sudo apt install ocrmypdf
• Windows: use Python/pip or install via package managers; Ghostscript and Tesseract are also needed

Run OCR

ocrmypdf input.pdf output_searchable.pdf

Optional:

ocrmypdf --deskew --clean input.pdf output_searchable.pdf

This:

• processes all pages
• adds a text layer
• keeps the original page images
• makes the PDF searchable

If you want plain text instead of searchable PDF

Use Tesseract on each page image

1. Convert PDF pages to images:

pdftoppm -png input.pdf page

2. OCR each page:

tesseract page-1.png page-1

3. Combine text files:

cat page-*.txt > output.txt

Programmatic option in Python

If you want to automate it:

import pytesseract
from pdf2image import convert_from_path

pages = convert_from_path("input.pdf", dpi=300)

all_text = []
for i, page in enumerate(pages, start=1):
    text = pytesseract.image_to_string(page)
    all_text.append(f"--- Page {i} ---\n{text}")

with open("output.txt", "w", encoding="utf-8") as f:
    f.write("\n\n".join(all_text))

You’ll need:

• pytesseract
• pdf2image
• Poppler
• Tesseract OCR installed on your system

Tips for better OCR

• Use 300 DPI or higher
• Ensure pages are deskewed
• Improve contrast if scans are faint
• Use the correct language:

tesseract input.png output -l eng

If you want, I can give you:

• a one-line command for your OS,
• a Python script for batch OCR,
• or help you choose the best tool for searchable PDF vs plain text.