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Reduce file size without losing quality.
Scanned documents often come out crooked, speckled, faded, or blurry. Our AI‑powered tool restores scanned PDFs to professional quality: auto‑deskew pages, remove dust spots, flatten background shadows, sharpen text, and increase DPI. Perfect for old books, office scans, legal archives, and any paper‑to‑PDF conversion. No software to install, and your files are automatically deleted after processing.
Did you know? Over 80% of scanned PDFs have correctable defects: skew, speckles, or uneven lighting. Our enhancement can turn a nearly unreadable scan into a crystal‑clear digital document.
Understanding the defects helps you apply the right fix.
Dirty scanner glass or paper fibres create small black/white dots across the page, distracting readers and confusing OCR.
Pages fed at an angle produce crooked text lines. Even 2‑3 degrees of tilt reduces readability and OCR accuracy.
Book scans have dark gradients near the spine; office scanners may have brighter centres. This unevenness disturbs the background.
Scanners often default to 150 DPI to save space, resulting in soft text and pixelated images when printed.
Bonus cause – paper texture: Old paper or rough stock creates background noise that appears as grain. Our noise reduction smooths it while preserving text edges.
Upload your scanned PDF – Our system analyses each page for skew, specks, lighting, and resolution.
Select enhancement options – Auto‑deskew, despeckle, background flattening, and upscale to 300 DPI. You can also manually adjust each.
Apply AI enhancement – The tool cleans, straightens, and sharpens the entire document. A real‑time preview shows before/after.
Download the improved PDF – The enhanced file is ready for printing, archiving, or OCR. Original page order and bookmarks are preserved.
Pro Tip: If you have a multi‑page book scan, enable "Auto‑split facing pages" to separate left and right pages, deskew each independently, and then merge them in order. This produces a clean, book‑like PDF.
Our scanner enhancement applies three core operations in order:
After these steps, we optionally upscale the resolution and apply text‑dedicated sharpening.
If your document was scanned at 150 DPI (common for office use), it will print poorly. Our AI super‑resolution upscales the image to 300 DPI while synthesizing realistic details. The result is often indistinguishable from a fresh 300 DPI scan – without rescanning the original paper. You can choose target DPI: 200 DPI (fast), 300 DPI (professional), or 600 DPI (archival).
Real‑world example: A university library scanned thousands of rare books at 150 DPI. After applying our enhancement (despeckle + deskew + upscale to 300 DPI), the PDFs became print‑ready, and OCR accuracy rose from 68% to 94%.
Upscaling to 300 DPI increases file size, but our smart compression (JPEG2000, Flate) reduces the overhead by up to 60% while preserving sharpness. Use the "Balanced" profile for most scans. For email attachments, choose "Compact" – the file will be much smaller but still far better than the original.
Tip: If file size is critical, apply despeckle and deskew only (no upscaling). The page will remain at original resolution, but noise and skew are fixed.
⚡ Need to adjust or standardise DPI without changing pixels?
Use our dedicated PDF DPI Changer to view, adjust, or unify the DPI metadata of embedded images. Perfect for pre‑press compliance, print workflow validation, and preparing files for commercial printing without altering visual quality.
Scanned PDFs often suffer from speckles (dust on scanner glass), skewed pages (uneven feeding), uneven lighting (dark shadows near the spine), low DPI (150 DPI typical), and background bleed‑through. Our enhancement cleans the image, straightens pages, normalizes contrast, and upscales to 300 DPI for crisp output.
Absolutely. 150 DPI is common for office scans, but it results in fuzzy prints. Our AI upscales the image to 300 DPI or higher while removing noise and sharpening text. The enhanced version often looks better than a new scan at 300 DPI because we also correct lighting and skew.
Upscaling to 300 DPI adds pixels, so file size may increase (e.g., 2‑5 MB → 8‑15 MB). However, our smart compression (JPEG2000, Flate) reduces overhead by up to 60% while retaining sharpness. For most scanned documents, the final size stays under 10 MB – still email friendly.
Our scanner‑optimized mode includes a despeckling filter that removes isolated black/white pixels caused by dust. You can adjust the despeckle strength (Low, Medium, High). For best results, scan at 300 DPI first, then run the enhancement with despeckle turned on.
Yes. The tool automatically detects page skew up to ±15° and rotates each page individually. You can also manually rotate pages if auto‑detection misses anything. Deskewing is critical before OCR – straight text lines improve recognition accuracy by up to 40%.
Absolutely. Book scans often have dark shadows near the spine. Our background equalization algorithm flattens the illumination, making the page background uniformly white. This is separate from standard brightness/contrast adjustments and works even on severely uneven scans.
No, enhancement improves visual quality but does not add a text layer. After you clean and sharpen the scan, run our OCR tool to convert the images into selectable, searchable text. Enhance first, then OCR – sharp images give much higher OCR accuracy.
Yes. All uploads are encrypted with TLS 1.3 and automatically deleted within 24 hours. We never use your documents for training or share them. An offline desktop version is available for organisations with strict security policies.
Yes, the tool is fully responsive and works on iOS and Android. Upload from cloud storage or local storage. Processing runs in the cloud, so your device does not need high processing power.
Upload your document and let AI remove noise, fix skew, and restore clarity in seconds.
Enhancing a PDF improves visual clarity by adjusting resolution, sharpening text edges, and increasing contrast between foreground and background elements. This process is particularly useful for scanned documents, blurry text, or faded paperwork.
Several factors may reduce the readability of a PDF document. Low-resolution scanning, aggressive compression, improper export settings, and camera-captured documents can all introduce blur or reduce contrast.
Modern PDF enhancement tools apply multiple processing techniques to improve readability.
PDF enhancement algorithms work by analyzing pixel density and grayscale distribution. Contrast adjustment increases the difference between text and background while sharpening filters reconstruct blurred edges. When combined with OCR preparation, enhancement dramatically improves machine readability.
Explore the full collection of tools in the PDF Enhancement Guide.