How do I enhance a scanned PDF?
Upload your scanned PDF, enable desired enhancement options (Auto Deskew, Remove Background, Clean Artifacts, Oversample to 300 DPI), select optimization level (None/1/2/3), then click 'Enhance PDF'. Download the improved PDF when processing completes.
What does 'Auto Deskew' do?
Auto Deskew automatically straightens tilted or crooked pages. It detects the text/content angle and rotates pages to be perfectly straight and aligned. Essential for phone photos, documents fed unevenly through scanners, and old crooked scans.
How do I rotate pages if they are upside-down or sideways?
Use the rotation buttons in the file preview area before enhancement. Click on a page thumbnail and use the rotate buttons to turn pages 90°, 180°, or 270°. The enhancement will process pages with the corrected orientation. This tool does not have automatic page rotation - manual rotation via preview area is required.
What does 'Remove Background' do?
Background removal eliminates paper discoloration (yellowing from age), coffee/water stains, shadows, scanner bed dirt, and noise. It turns off-white, gray, or stained backgrounds into clean white, dramatically improving document appearance and readability. Great for old documents and dirty scans.
What does 'Clean Artifacts' do?
Clean Artifacts removes scanning speckles (dust spots on scanner glass), JPEG compression artifacts, salt-and-pepper noise, and fine scanning lines. Results in crisp, clean pages that look professional. WARNING: This option may leave visual artifacts - always review results carefully before using the enhanced PDF.
What does 'Oversample to 300 DPI' do?
Oversampling increases the resolution of low-quality scans to 300 DPI (dots per inch), which is the standard for high-quality printing. This improves clarity and sharpness but increases file size. Only enable if your original scan has low resolution (below 300 DPI). High-resolution scans don't benefit from this option.
How do optimization levels work?
Optimization controls file size vs image quality. None (0) = no compression, largest file, perfect quality. Low (1) = slight reduction, near-perfect quality. Medium (2) = balanced (recommended). High (3) = smallest file, slight quality loss. Higher levels make images slightly blurrier but significantly reduce file size.
Does this tool add OCR or text layer?
No. This tool only improves image quality visually - it does NOT add text layer or OCR. The output is still a scanned image-based PDF, just cleaner and straighter. For searchable text, use our 'Scan to Searchable PDF' tool after enhancement.
Can I use this for phone photos of documents?
Absolutely! This tool works excellently with documents photographed using mobile phone cameras. Enable deskew to straighten, remove background to eliminate shadows and uneven lighting, and clean final for crisp results. Many users prefer phone photos + enhancement over traditional scanners.
Should I enhance before or after OCR?
Always enhance BEFORE OCR. Clean, straight, high-contrast scans yield 20-30% better OCR accuracy. Use this enhancement tool first, then use our 'Scan to Searchable PDF' tool for OCR. Enhanced images with clean backgrounds and straight text lines are much easier for OCR engines to read.
What types of documents work best?
Works best with text documents, forms, receipts, invoices, contracts, letters, book pages, and typed documents. Photos, artwork, and graphics may see mixed results. Black text on white/colored backgrounds works perfectly. Color documents are supported.
Can I remove watermarks or stamps?
No. This tool removes noise, stains, and artifacts (unintentional marks) but does NOT remove intentional content like watermarks, stamps, signatures, or logos. Background removal may lighten some light-colored stamps but won't fully remove them.
What happens to my PDF during enhancement?
Small files (10MB or less) process on our server but are never stored - they process and return immediately. Large files (over 10MB) are temporarily stored during processing and automatically deleted after 2 hours for privacy.
Is there a file size limit?
Yes, PDFs up to 200MB are supported. This handles large multi-page scanned documents, books, and document collections.