How to Make Scanned PDFs Searchable with OCR - Complete Guide

Add a searchable text layer to your scanned PDF documents using FunPDF's Scan to Searchable PDF tool.

What is OCR?

OCR (Optical Character Recognition) converts images of text into actual searchable and selectable text. This technology:

Enables Text Search:

• Use Ctrl+F to find any word or phrase
• Quickly locate specific information in long documents
• Search through archives of scanned documents

Allows Copy-Paste:

• Select and copy text directly from scanned PDFs
• Extract text without manual retyping
• Quote and reference content easily

Preserves Original Appearance:

• OCR text layer is invisible - sits behind the image
• Document looks exactly like the original scan
• Visual fidelity, layout, and colors unchanged
• Perfect for legal documents requiring authenticity

Improves Accessibility:

• Screen readers can read the text aloud
• Complies with accessibility standards (WCAG, Section 508)
• Helps visually impaired users access scanned content

Step-by-Step Guide

1. Upload Your Scanned PDF

Upload your scanned PDF to the FunPDF Editor:

Using Drag and Drop:

• Drag your scanned PDF file into the editor window
• Drop it anywhere on the page
• File loads automatically

Using Upload Button:

• Click "Upload PDFs" or "Add files" button
• Select your scanned PDF (up to 200MB)
• Click "Open" to upload

Supported Files:

• Image-based PDFs from scanners
• Phone camera photos of documents
• Photocopies saved as PDF
• Screenshots and digital scans

2. Select OCR Tool

• Open the Scan to Searchable PDF tool from the right sidebar
• Or select it from the tools dropdown menu
• The OCR settings panel appears

3. Configure OCR Options

Language Selection

Choose the language of your document's text for accurate recognition:

Supported Languages (12 total):

• English (eng)
• Chinese Simplified (chi_sim)
• Chinese Traditional (chi_tra)
• Japanese (jpn)
• Korean (kor)
• Spanish (spa)
• French (fra)
• German (deu)
• Italian (ita)
• Portuguese (por)
• Russian (rus)
• Arabic (ara)

Important: Select the correct language for best OCR accuracy. Wrong language selection can result in garbled or incorrect text.

Page Range

All Pages (Recommended):

• Process entire document
• Best for complete searchability

Custom Ranges:

• Specify pages: "1-10, 15, 20-25"
• Single pages: "5, 8, 12"
• Ranges: "1-5" for pages 1 through 5
• Mixed: "1-10, 15, 20-25" for multiple sections
• Use for large files to save time
• Process only relevant sections

Text Handling Mode (If PDF Contains Text)

The tool automatically detects if your PDF already has text. Choose how to handle it:

Skip Text (Default - Recommended):

• OCR only image pages without text
• Keep existing text untouched
• Fastest option for mixed PDFs
• Best for PDFs with some text already

Redo OCR:

• Replace existing text with fresh OCR
• Use if original text is inaccurate
• Useful for poorly extracted text

Force OCR:

• OCR all pages regardless of existing text
• Creates new text layer on all pages
• Use when you want uniform OCR across entire document

Output Format

PDF (Standard - Recommended):

• Standard PDF format
• Maximum compatibility
• Use for everyday documents

PDF/A-2 (Archival):

• Long-term preservation format
• For legal compliance and archiving
• Embeds all fonts and resources
• Ensures document looks identical decades later

PDF/A-3 (Archival with Attachments):

• Same as PDF/A-2
• Plus support for embedded files
• For complex archival requirements

When to Use PDF/A:

• Legal documents requiring preservation
• Government records and official archives
• Institutional repositories
• Long-term storage (10+ years)

Compression Level

None:

• No compression
• Largest file size
• Maximum quality
• Use when file size doesn't matter

Low (1):

• Minimal compression
• Near-perfect quality
• Large files
• Good for print documents

Medium (2) - Recommended:

• Balanced quality and size
• Very good quality maintained
• Reasonable file size
• Best for most use cases

High (3):

• Maximum compression
• Smallest file size
• Slight quality reduction
• Good for storage optimization

4. Start OCR Processing

Click "Start OCR" to begin:

Small Files (≤10MB):

• Process instantly on server
• Files not stored
• Results in seconds

Large Files (>10MB):

• Upload to secure temporary storage
• Process in background
• Real-time progress bar shows:
  • Current page being processed
  • Overall progress percentage
  • Status messages
• Files auto-delete after 2 hours
• Can cancel processing if needed

5. Download Result

After OCR completes:

• Click "Download" to save the searchable PDF
• Test searchability: Open in PDF viewer, press Ctrl+F, search for a word
• Text layer is invisible but fully functional
• Document looks identical to original scan

Understanding OCR Results

OCR Accuracy

Factors Affecting Accuracy:

High Accuracy (95-99%):

• Clean, high-resolution scans (300+ DPI)
• Good contrast between text and background
• Clear, printed text
• Correct language selected

Medium Accuracy (80-95%):

• Lower resolution scans (150-300 DPI)
• Some background noise
• Faded or light text
• Slight tilt or skew

Low Accuracy (<80%):

• Very low resolution (<150 DPI)
• Blurry or out-of-focus scans
• Heavy background noise, stains
• Severely tilted or distorted pages
• Wrong language selected

Not Suitable for OCR:

• Handwritten or cursive text (very low accuracy)
• Artistic or stylized fonts
• Severely damaged documents
• Images instead of text

Improving OCR Quality

Before OCR:

1. Use Scanned PDF Enhancement tool first
2. Enable deskew to straighten tilted pages
3. Enable background removal to clean stains
4. Enable artifact cleaning for clearer text

During OCR:

1. Select correct document language
2. Choose medium or low compression for better quality
3. Process a test page first to verify accuracy

Use Cases

Make Scanned Contracts Searchable

• Search for specific clauses instantly
• Find all instances of terms or names
• Quick reference without reading entire document
• Essential for legal review

Digitize Paper Archives

• Convert old letters, reports, meeting minutes
• Create searchable digital library
• Find historical information quickly
• Preserve while adding modern functionality

Extract Text from Academic Papers

• Copy citations and quotes without retyping
• Search for specific research topics
• Create reference databases
• Extract data for analysis

Searchable Receipt Archives

• Find specific purchases by vendor or item
• Track expenses by searching keywords
• Organize accounting records
• Quick retrieval for tax or audit purposes

Accessibility Compliance

• Screen readers require text to read aloud
• Add text layer for visually impaired users
• Meet WCAG and Section 508 requirements
• Make documents inclusive

Best Practices

For Standard Documents

• Language: Select document language
• Pages: All pages
• Format: Standard PDF
• Compression: Medium (2)
• Text handling: Skip text (default)

For Large Documents

• Process in batches (custom page ranges)
• Use high compression to reduce file size
• Monitor progress, cancel if needed
• Download and verify each batch

For Archival Documents

• Format: PDF/A-2 or PDF/A-3
• Compression: Low or Medium
• Process all pages
• Preserve for long-term storage

For Low-Quality Scans

1. Use PDF Enhancement first:
   • Enable deskew
   • Enable background removal
   • Enable clean artifacts
2. Then OCR the enhanced PDF
3. Results will be significantly better

Troubleshooting

OCR Accuracy Too Low

Causes:

• Wrong language selected
• Poor scan quality (blurry, faded)
• Low resolution
• Heavy background noise

Solutions:

• Verify correct language is selected
• Use PDF Enhancement to improve scan quality
• Re-scan at higher resolution (300+ DPI recommended)
• Clean original document before scanning

Handwritten Text Not Recognized

Explanation:

• OCR works best on printed text
• Handwriting has very low accuracy
• Cursive text especially problematic

Solution:

• Manual transcription required for handwriting
• OCR not suitable for handwritten documents

PDF Already Contains Text

Not an error - This is smart text detection:

• Tool automatically detects existing text
• Choose text handling mode:
  • Skip text: Keep existing, OCR images only (recommended)
  • Redo OCR: Replace existing text
  • Force OCR: OCR all pages

File Too Large (>200MB)

Solutions:

• Split PDF into smaller parts
• OCR each part separately
• Merge searchable parts if needed
• Or process with custom page ranges in batches

Processing Failed

Solutions:

• Check file is valid PDF
• Try smaller page range first
• Enhance scan quality with PDF Enhancement
• Refresh page and retry
• See Why Did My Conversion Fail?

Privacy and Security

Small Files (≤10MB)

• Process on server without storage
• Not stored
• Immediate results
• Maximum privacy

Large Files (>10MB)

• Temporarily stored during processing
• Automatically deleted after 2 hours
• Secure temporary storage
• Files don't stay permanently

See Is My Data Secure? for full privacy details.

Next Steps

• Scan to Searchable PDF Tool - Start adding OCR now
• Scanned PDF Enhancement - Improve scan quality first
• PDF to Word - Convert searchable PDF to editable Word
• Compress PDF - Reduce file size after OCR

Start making your scanned PDFs searchable with Scan to Searchable PDF now!