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Reduce file size without losing quality.
If your PDF looks pixelated, blurry, or dull, you don't have to accept poor quality. Our online enhancement tool restores sharpness, increases effective resolution, and removes compression artifacts — all without installing any software. Whether your document suffers from low‑DPI scanning, heavy compression, or improper conversion, our AI engine brings back crisp text and clear images.
Did you know? Over 70% of PDFs shared via email or cloud storage suffer from some degree of image or text quality degradation due to automatic compression. Our tool reverses this damage using advanced deblurring and super‑resolution algorithms originally developed for medical and satellite imaging.
Understanding the source of low quality is the first step to fixing it.
Many scans are done at 150 DPI to save space. When viewed on modern high‑resolution screens or printed, every pixel becomes visible, creating a blocky, soft appearance. 300 DPI is the standard for professional print.
JPEG quality below 50% discards high‑frequency details, causing characteristic blur and 8×8 block artifacts around text and edges. Our adaptive deblocking reverses this damage.
Word, PowerPoint, and many PDF printers downsample images to 150 DPI by default. Once downsampled, the original detail is lost unless we use AI to intelligently guess missing pixels.
Some PDF creators convert entire pages or text blocks into images (bitmaps). The text becomes pixelated and fuzzy. Our text‑dedicated sharpening filter enhances edge contrast without distorting character shapes.
Bonus cause – repeated re‑saving: Each time you re‑save a PDF, images are recompressed. After several cycles, quality degrades exponentially. Always keep a master copy in an editable format.
Upload your low quality PDF – Drag and drop or select your file. Encrypted with TLS 1.3. Our system analyzes each page to detect pixelation, blur, and compression artifacts.
Apply AI resolution enhancement – For low DPI, we upscale images using deep‑learning super‑resolution. You can choose a target DPI (150 for web, 300 for print, 600 for archival).
Sharpen text and remove artifacts – Separate filters for text (edge‑preserving sharpening) and images (adaptive unsharp mask) are applied. You can manually adjust strength, noise reduction, and edge protection.
Download the improved PDF – Your enhanced document is ready. Choose output compression (Quality First, Balanced, or Compact). Original layout, hyperlinks, and form fields are preserved. Files auto‑delete after 24 hours.
Pro Tip: Use the "Deep Restoration" preset for documents that are both blurry and pixelated. It performs two passes: first de‑noising and upscaling, then targeted sharpening. This avoids over‑sharpening halos while recovering maximum detail.
DPI (dots per inch) tells you how many printed pixels fit into one physical inch. For on‑screen viewing, 72–96 DPI is acceptable, but 4K and Retina screens make lower DPI images look blurry. For professional printing, always target 300 DPI. Archival scans (fine art, old photographs) benefit from 600 DPI. Our tool reports the current average DPI of your PDF and automatically suggests a target based on your intended use (web, print, or archival).
Typical DPI recommendations:
Scanned PDFs come with unique issues: optical blur from the scanner lens, sensor noise, uneven lighting, and paper texture. Our dedicated scan enhancement pipeline runs four sequential operations: (1) despeckling to remove dust and scratches, (2) background equalization to whiten the page, (3) Wiener filter deblurring tuned for scanner optics, and (4) adaptive thresholding to convert grayscale into crisp black‑and‑white text. After improvement, you can use our OCR tool to add a fully searchable text layer. In tests, combining enhancement with OCR raised text recognition accuracy by up to 35% compared to OCR on the raw scan.
Real‑world example: A university library scanned thousands of historical newspapers at 150 DPI. After batch enhancement, every page became legible, and OCR accuracy improved from 72% to 94%, making the entire archive searchable.
After improving resolution and sharpness, the file size naturally increases because you are adding detail. A 2x upscale (to 300 DPI) multiplies the pixel count by 4, which can increase size by 200‑300%. However, our balanced compression uses JPEG2000 and Flate encoding to reduce the final size by up to 60% while retaining 95% of the visual improvement. Choose from three modes: Quality First (largest file, best sharpness), Balanced (recommended for most users), or Compact (smallest file, still far better than the original).
File size guide: A typical 10‑page PDF with medium‑quality images (2‑5 MB) may become 6‑15 MB after enhancement; balanced compression brings it down to 3‑8 MB – still well within the 25 MB limit of most email services.
⚡ 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.
Yes, to a large extent. If the degradation is due to moderate compression or low DPI, our AI enhancement can recover most detail. For severely pixelated or repeatedly compressed files, some information is lost permanently, but the improvement is still dramatic — often turning an unreadable document into a usable one.
The main culprits are low scanning resolution (under 200 DPI), aggressive JPEG compression, downsampling during export (e.g., from Word), rasterized text (text turned into an image), and repeated re-saving of the same PDF. Each factor smears fine details and creates visible artifacts.
Yes, because enhancing resolution adds detail. A 2x upscale roughly quadruples the pixel count, which can increase size by 200‑300%. Our smart compression modes (Quality First, Balanced, Compact) reduce this overhead by up to 60% while preserving most of the visual gain.
Absolutely. Scanned PDFs are our most common use case. Our enhancement removes dust, levels uneven illumination, applies optical deblurring, and sharpens text. After enhancement, you can run OCR to make the content searchable – combining both improves OCR accuracy by up to 35%.
Resolution is the total pixel count (e.g., 1920×1080). DPI (dots per inch) tells how densely those pixels are printed. For the same resolution, higher DPI yields a smaller printed size but sharper detail. We typically upscale to 300 DPI for print or 150 DPI for web use.
Yes, especially for severe degradation. AI models learn from millions of examples and can reconstruct missing textures and letter shapes. Traditional filters only increase contrast at edges, which amplifies noise and cannot recover lost detail. Our AI classifies the type of blur (motion, Gaussian, compression) and applies the optimal restoration.
Not automatically. Enhancement improves visual appearance only. For scanned image-only PDFs, after sharpening you should run our OCR tool to add a fully searchable and selectable text layer. The order matters: enhance first, then OCR.
Yes. All uploads are encrypted with TLS 1.3, and files are automatically deleted from our servers within 24 hours. We never train AI on your documents. An offline desktop version is also available for maximum privacy.
Yes, the interface is fully responsive and works on iOS and Android. You can upload from your camera roll, cloud storage, or local storage. Processing runs in the cloud, so your device only needs a browser and an internet connection.
Upload your document and let our AI restore sharpness, resolution, and professional 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.