PDF Scan Cleaner
Clean and enhance scanned PDF documents with advanced noise reduction, automatic deskewing, and sharpening filters. Remove speckles, correct tilted pages, and improve text clarity for professional document quality.
Drop your scanned PDF here
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What is PDF Scan Cleaner?
The PDF Scan Cleaner improves the quality of scanned PDF documents. It reduces speckles and grain, corrects tilted pages through deskewing, and sharpens text edges for better readability. You pick a cleaning preset or adjust noise reduction, deskew, and sharpening settings individually. All processing happens in the browser using the Canvas API.
How does PDF Scan Cleaner work?
This tool renders each PDF page to a canvas using pdf.js, then applies image processing filters. Noise reduction uses median filtering to smooth out speckles. Deskewing detects the dominant text angle and rotates the page to straighten it. Sharpening uses convolution filters to enhance text edges. The processed pages are reassembled into a new PDF.
Key Features
- Noise reduction with adjustable intensity to remove speckles and grain
- Automatic deskewing that corrects tilted pages
- Sharpening filters that enhance text clarity
- Presets for minimal, basic, enhanced, and aggressive cleaning
- Real-time before and after preview
- Processes files locally in the browser with no uploads
- Supports PDFs up to 100MB
- Works with any standard scanned PDF
Common Use Cases
Cleaning old scanned documents
Remove dust speckles, scanner noise, and grain from documents that were scanned years ago on older equipment.
Preparing documents for OCR
Clean a scanned PDF before running OCR software, since cleaner images produce more accurate text recognition results.
Fixing skewed scans
Straighten pages that were fed into the scanner at an angle, so the text lines are level and the document looks professional.
Improving readability of faded text
Apply sharpening to documents where the original ink has faded, making text edges crisper and easier to read.
How to Use This Tool
Upload a scanned PDF
Click the upload area or drag your scanned PDF onto the page.
Choose a cleaning preset
Select Minimal, Basic, Enhanced, or Aggressive, or adjust noise reduction, deskew, and sharpening settings individually.
Process the document
Click Clean PDF to apply the selected settings to every page.
Preview and download
Check the before and after comparison, then download the cleaned PDF.
Pro Tips
- 1
Start with the Basic preset. It handles most scanned documents well without over-processing.
- 2
Keep noise reduction below 30 percent for documents with fine details like small fonts or line drawings.
- 3
Deskewing works best on documents with clear horizontal text lines.
- 4
For very old or damaged scans, try the Enhanced preset before adjusting individual settings.
- 5
Keep a copy of the original scan in case the cleaning settings are too aggressive.
- 6
Run noise reduction before sharpening, not after. Sharpening amplifies whatever is on the page, so applying it to grain and speckles makes them more visible. The built-in presets already follow this order.
Frequently Asked Questions
What scanning problems can this tool fix?
It handles speckles, dust particles, scanner grain, compression artifacts, tilted pages, and soft or faded text. It does not perform OCR, so it cannot convert images of text into selectable text.
Does it work on all types of scanned documents?
It works on text documents, forms, blueprints, and mixed-content pages. Documents scanned at 300 DPI or higher tend to produce the best results.
Will cleaning reduce text readability?
The tool is designed to improve readability. Moderate settings (20 to 40 percent sharpening) enhance text without creating artifacts. Very aggressive settings can over-sharpen and introduce noise, so preview before downloading.
Is my PDF uploaded to a server?
No. All image processing happens in your browser using JavaScript and the Canvas API. The file never leaves your device.
Can I undo the cleaning after processing?
The changes are baked into the downloaded PDF. To start over, re-upload the original file with different settings.
Will the cleaned PDF be larger than the original?
Often yes. The PDF Scan Cleaner rasterizes each page through canvas and reassembles them as image PDFs, which loses the original PDF's compression and any embedded text layer. A 5 MB scanned PDF can grow to 10-20 MB after cleaning. If size matters, run the output through a PDF compressor afterwards.
What DPI should I scan at for best cleaning results?
300 DPI grayscale is the sweet spot for text documents. It captures enough detail for noise reduction and sharpening to work without producing huge files. Use 600 DPI for archival scans, photographs, or documents with very fine print. Anything below 200 DPI loses too much information for the filters to recover.
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